Adobe RGB V sRGB

R
Posted By
Roberto
Jun 20, 2005
Views
1940
Replies
58
Status
Closed
Why shoot sRGB if your camera and post production software can support Adobe RGB colour space as well?

Adobe RGB has a greater colour space, so why not shoot in Adobe RGB and if need be, convert in post production?

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J
johnastovall
Jun 20, 2005
On Mon, 20 Jun 2005 19:55:47 +0100, "Russell" wrote:

Why shoot sRGB if your camera and post production software can support Adobe RGB colour space as well?

Adobe RGB has a greater colour space, so why not shoot in Adobe RGB and if need be, convert in post production?

You are assuming here one isn’t shooting RAW. For ACR I work in the ProPhoto space with 16 bit channels.

The space you set in the camera has no affect on the Raw file.

******************************************************

"I have been a witness, and these pictures are
my testimony. The events I have recorded should
not be forgotten and must not be repeated."

-James Nachtwey-
http://www.jamesnachtwey.com/
H
Hecate
Jun 21, 2005
On Mon, 20 Jun 2005 17:21:44 -0400, "Charles Schuler" wrote:

http://www.cambridgeincolour.com/tutorials/sRGB-AdobeRGB1998 .htm
Whilst he makes some interesting points for people shooting in RAW, as he would admit because it’s 16 bit, you should stick with AdobeRGB if possible. What he skates over in his comparison of colour space is that AdobeRGB maps more closely to the CYMK colour space than does sRGB. He may be able to find specific examples where a particular printer colour profile negates this benefit, but that doesn’t make his assertion accurate over all.



Hecate – The Real One

Fashion: Buying things you don’t need, with money
you don’t have, to impress people you don’t like…
S
stacey
Jun 21, 2005
Russell wrote:

Why shoot sRGB if your camera and post production software can support Adobe RGB colour space as well?

If the output device doesn’t support it, there is no good reason to do this. If it does, then there is.

Adobe RGB has a greater colour space, so why not shoot in Adobe RGB and if need be, convert in post production?

Because sometimes weird things can happen in the conversion. Been there done that one. Best way is shoot RAW and then you can use whichever colorspace fits the output.



Stacey
R
Roberto
Jun 21, 2005
Hello John

Thank you for your post. I didn’t understand that the space set on the camera has no effect with RAW images. In which case, your suggestion of ProPhoto space with 16 bit channels sounds logical.

"John A. Stovall" wrote in message
You are assuming here one isn’t shooting RAW. For ACR I work in the ProPhoto space with 16 bit channels.

The space you set in the camera has no affect on the Raw file.
BT
Bill Tuthill
Jun 21, 2005
In rec.photo.digital Russell wrote:
Why shoot sRGB if your camera and post production software can support Adobe RGB colour space as well?

Adobe RGB has a greater colour space, so why not shoot in Adobe RGB and if need be, convert in post production?

If you’re going to the trouble of putting Adobe RGB into your workflow, thus choking off a huge range of available software, why not go all the way and use a well-designed colorspace like ProPhoto RGB?
J
johnastovall
Jun 21, 2005
On Tue, 21 Jun 2005 18:41:22 +0100, "Russell" wrote:

Hello John

Thank you for your post. I didn’t understand that the space set on the camera has no effect with RAW images. In which case, your suggestion of ProPhoto space with 16 bit channels sounds logical.

I suggest you get a copy of _Real World Camera Raw with Photoshop CS2: Industrial-Strength Production Techniques_ by Bruce Fraser.

It has a great section on Color space. If you want more about Color space in the complete work flow see:

_Real World Color Management: Industrial-Strength Production Techniques_ by Bruce Fraser, Chris Murphy, Fred Bunting
************************************************************ ****

"Anarchism is both a religious faith and a rational philosophy; and many of its anomalies are the product of the clash between the two, and of the tensions between the different kinds of temperament which they represent."

_The Anarchists_
James Joll – 1964
R
Roberto
Jun 22, 2005
I will look into the books. Is seems Bruce Fraser is a very knowledgeable guy on this subject.

"John A. Stovall" wrote in message
I suggest you get a copy of _Real World Camera Raw with Photoshop CS2: Industrial-Strength Production Techniques_ by Bruce Fraser.
It has a great section on Color space. If you want more about Color space in the complete work flow see:

_Real World Color Management: Industrial-Strength Production Techniques_ by Bruce Fraser, Chris Murphy, Fred Bunting
M
Marcel
Sep 10, 2005
"Bill Tuthill" wrote in message
In rec.photo.digital Russell wrote:

If you’re going to the trouble of putting Adobe RGB into your workflow, thus choking off a huge range of available software, why not go all the
way
and use a well-designed colorspace like ProPhoto RGB?

Reading Scott Kelby, the first thing he suggests is replacing sRGB by Adobe RGB 98.
Most photographer, I thought would shy away from sRGB.
When I bought my Canon XT, I asked about that choice and was told if you use Adobe Photoshop, it’s better to choose Adobe RGB.
Why introduce ProPhoto RGB?
Could you please enlighten me?
J
johnastovall
Sep 10, 2005
On Sat, 10 Sep 2005 14:39:37 -0400, "Celcius" wrote:

"Bill Tuthill" wrote in message
In rec.photo.digital Russell wrote:

If you’re going to the trouble of putting Adobe RGB into your workflow, thus choking off a huge range of available software, why not go all the
way
and use a well-designed colorspace like ProPhoto RGB?

Reading Scott Kelby, the first thing he suggests is replacing sRGB by Adobe RGB 98.
Most photographer, I thought would shy away from sRGB.
When I bought my Canon XT, I asked about that choice and was told if you use Adobe Photoshop, it’s better to choose Adobe RGB.
Why introduce ProPhoto RGB?
Could you please enlighten me?

Larger Color Gamut is why.

Go read: Real World Camera Raw with Photoshop CS2: Industrial-Strength Production Techniques by Bruce Fraser

And:

Real World Color Management: Industrial-Strength Production Techniques by Bruce Fraser, Chris Murphy, Fred Bunting

*********************************************************

"I have been a witness, and these pictures are
my testimony. The events I have recorded should
not be forgotten and must not be repeated."

-James Nachtwey-
http://www.jamesnachtwey.com/
LN
Linda Nieuwenstein
Sep 10, 2005
"John A. Stovall" wrote
Real World Color Management: Industrial-Strength Production Techniques by Bruce Fraser, Chris Murphy, Fred Bunting

I’ve not read the other one you suggested, but I’ve read this one, and agree it is a very good read. I find there are too many authors that tackle this this topic who don’t have a grasp of it themselves, thus, perpetuating a whole lot of myths and misconceptions. A frew books I’ve read simply provide contradictory information it seems. Without a lot of personal trial and error it is almost impossible to figure out which authors know what they are talking about and which onese don’t get it.

Take care,
Linda
J
johnastovall
Sep 10, 2005
On Sat, 10 Sep 2005 18:49:40 -0300, "Linda Nieuwenstein" wrote:

"John A. Stovall" wrote
Real World Color Management: Industrial-Strength Production Techniques by Bruce Fraser, Chris Murphy, Fred Bunting

I’ve not read the other one you suggested, but I’ve read this one, and agree it is a very good read. I find there are too many authors that tackle this this topic who don’t have a grasp of it themselves, thus, perpetuating a whole lot of myths and misconceptions. A frew books I’ve read simply provide contradictory information it seems. Without a lot of personal trial and error it is almost impossible to figure out which authors know what they are talking about and which onese don’t get it.

Those two books are what I consider required reading for any one wanting to do quality digital prints.

*********************************************************

"I have been a witness, and these pictures are
my testimony. The events I have recorded should
not be forgotten and must not be repeated."

-James Nachtwey-
http://www.jamesnachtwey.com/
H
Hecate
Sep 11, 2005
On Sat, 10 Sep 2005 23:53:08 GMT, John A. Stovall
wrote:

On Sat, 10 Sep 2005 18:49:40 -0300, "Linda Nieuwenstein" wrote:

"John A. Stovall" wrote
Real World Color Management: Industrial-Strength Production Techniques by Bruce Fraser, Chris Murphy, Fred Bunting

I’ve not read the other one you suggested, but I’ve read this one, and agree it is a very good read. I find there are too many authors that tackle this this topic who don’t have a grasp of it themselves, thus, perpetuating a whole lot of myths and misconceptions. A frew books I’ve read simply provide contradictory information it seems. Without a lot of personal trial and error it is almost impossible to figure out which authors know what they are talking about and which onese don’t get it.

Those two books are what I consider required reading for any one wanting to do quality digital prints.
The RAW book is only required reading if you have digital files i.e. from a camera.

But the colour management book is excellent.



Hecate – The Real One

Fashion: Buying things you don’t need, with money
you don’t have, to impress people you don’t like…
LN
Linda Nieuwenstein
Sep 11, 2005
"Hecate" wrote
John A. Stovall wrote:
Those two books are what I consider required reading for any one wanting to do quality digital prints.

The RAW book is only required reading if you have digital files i.e. from a camera.

But the colour management book is excellent.

Thanks John and Hecate. I’ll invest in the first one too. It can’t hurt to get more info, there’s plenty to go around. I still prefer book reading over sitting at a computer reading from the Web (or e-book etc…). I think that will never change especially in the Winter when I can sit near the warmth of the fire while reading. My computer would melt!

Take care,
linda
J
johnastovall
Sep 11, 2005
On Sat, 10 Sep 2005 23:53:08 GMT, John A. Stovall
wrote:

On Sat, 10 Sep 2005 18:49:40 -0300, "Linda Nieuwenstein" wrote:

"John A. Stovall" wrote
Real World Color Management: Industrial-Strength Production Techniques by Bruce Fraser, Chris Murphy, Fred Bunting

I’ve not read the other one you suggested, but I’ve read this one, and agree it is a very good read. I find there are too many authors that tackle this this topic who don’t have a grasp of it themselves, thus, perpetuating a whole lot of myths and misconceptions. A frew books I’ve read simply provide contradictory information it seems. Without a lot of personal trial and error it is almost impossible to figure out which authors know what they are talking about and which onese don’t get it.

Those two books are what I consider required reading for any one wanting to do quality digital prints.

True, I was responding in the rec.photo.digital and didn’t thank all the graphic artist who work from other image sources.

*********************************************************

"I have been a witness, and these pictures are
my testimony. The events I have recorded should
not be forgotten and must not be repeated."

-James Nachtwey-
http://www.jamesnachtwey.com/
D
Dave
Sep 11, 2005
On Sun, 11 Sep 2005 12:27:00 -0300, "Linda Nieuwenstein" wrote:


Thanks John and Hecate. I’ll invest in the first one too. It can’t hurt to get more info, there’s plenty to go around. I still prefer book reading over sitting at a computer reading from the Web (or e-book etc…). I think that will never change especially in the Winter when I can sit near the warmth of the fire while reading. My computer would melt!

Take care,
linda

and here… where winter temperatures sometimes is
as high as 28° Celsius?
That could be the reason why I love reading in HTML;
at least this is where the ceiling fan are:-)

Dave
M
Marcel
Sep 11, 2005
"John A. Stovall" wrote in message
wrote:

Larger Color Gamut is why.

Go read: Real World Camera Raw with Photoshop CS2: Industrial-Strength Production Techniques by Bruce Fraser

And:

Real World Color Management: Industrial-Strength Production Techniques by Bruce Fraser, Chris Murphy, Fred Bunting

Thanks John for your consideration and empathy. Perhaps you could have been more "civil" in your response: "Go read…". You see, I’ve been into photography quite a while now and I’m sorry to say I hadn’t heard of ProPhoto RGB. Next time, pass me out. I don’t need this sort of help ;-(
Marcel
J
johnastovall
Sep 11, 2005
On Sun, 11 Sep 2005 14:10:51 -0400, "Celcius" wrote:

"John A. Stovall" wrote in message
wrote:

Larger Color Gamut is why.

Go read: Real World Camera Raw with Photoshop CS2: Industrial-Strength Production Techniques by Bruce Fraser

And:

Real World Color Management: Industrial-Strength Production Techniques by Bruce Fraser, Chris Murphy, Fred Bunting

Thanks John for your consideration and empathy. Perhaps you could have been more "civil" in your response: "Go read…". You see, I’ve been into photography quite a while now and I’m sorry to say I hadn’t heard of ProPhoto RGB. Next time, pass me out. I don’t need this sort of help ;-(
Marcel

Go read is the best advice one can give those that don’t know.

I see you don’t want to learn but just told.

*********************************************************

"I have been a witness, and these pictures are
my testimony. The events I have recorded should
not be forgotten and must not be repeated."

-James Nachtwey-
http://www.jamesnachtwey.com/
M
Marcel
Sep 11, 2005
"Go Read" is like "Go fetch!"
I suppose you may know a lot about photography, but very little about education. I suppose this is farfetched and utterly lost on you. Marcel

"John A. Stovall" wrote in message
On Sun, 11 Sep 2005 14:10:51 -0400, "Celcius" wrote:

"John A. Stovall" wrote in message
wrote:

Larger Color Gamut is why.

Go read: Real World Camera Raw with Photoshop CS2: Industrial-Strength Production Techniques by Bruce Fraser

And:

Real World Color Management: Industrial-Strength Production Techniques by Bruce Fraser, Chris Murphy, Fred Bunting

Thanks John for your consideration and empathy. Perhaps you could have
been
more "civil" in your response: "Go read…". You see, I’ve been into photography quite a while now and I’m sorry to
say I
hadn’t heard of ProPhoto RGB. Next time, pass me out. I don’t need this
sort
of help ;-(
Marcel

Go read is the best advice one can give those that don’t know.
I see you don’t want to learn but just told.

*********************************************************
"I have been a witness, and these pictures are
my testimony. The events I have recorded should
not be forgotten and must not be repeated."

-James Nachtwey-
http://www.jamesnachtwey.com/
J
johnastovall
Sep 11, 2005
On Sun, 11 Sep 2005 15:12:23 -0400, "Celcius" wrote:

"Go Read" is like "Go fetch!"
I suppose you may know a lot about photography, but very little about education. I suppose this is farfetched and utterly lost on you.

I’ve taught graduate level courses in College. "Go Read" is what Graduate Students are told to do. We would hand out things called "Reading Lists" at the start of the Semester and students were expected to read all the material on them and be responsible for it regardless whether it was discussed in class or not.

If you really want to know something you’ll go read it not sit around and wait for others to waste time telling you what they learned by reading.

I don’t believe in treating fools lightly, either.
********************************************************

"…bray a fool in a morter with wheat,
yet shall not his folly be beaten out of him;.."

"The Marriage of Heaven and Hell"
William Blake
D
Dave
Sep 11, 2005
On Sun, 11 Sep 2005 19:34:48 GMT, John A. Stovall
wrote:

On Sun, 11 Sep 2005 15:12:23 -0400, "Celcius" wrote:

I’ve taught graduate level courses in College. "Go Read" is what Graduate Students are told to do. We would hand out things called "Reading Lists" at the start of the Semester and students were expected to read all the material on them and be responsible for it regardless whether it was discussed in class or not.

I think you are a liar. You rather sound like a newbie
spending time in a library and do not really know
how to answer questions like those asked.
A group like this can do without your kind.

Dave
LW
Lester Wareham
Sep 11, 2005
"Celcius" wrote in message
"Bill Tuthill" wrote in message
In rec.photo.digital Russell wrote:

If you’re going to the trouble of putting Adobe RGB into your workflow, thus choking off a huge range of available software, why not go all the
way
and use a well-designed colorspace like ProPhoto RGB?

Reading Scott Kelby, the first thing he suggests is replacing sRGB by Adobe
RGB 98.
Most photographer, I thought would shy away from sRGB.
When I bought my Canon XT, I asked about that choice and was told if you use
Adobe Photoshop, it’s better to choose Adobe RGB.
Why introduce ProPhoto RGB?
Could you please enlighten me?

Take a look at this
http://www.luminous-landscape.com/cgi-bin/forum/ikonboard.cg i?act=ST;f=5;t=1604
M
Marcel
Sep 11, 2005
"Lester Wareham" wrote in message
"Celcius" wrote in message
"Bill Tuthill" wrote in message
In rec.photo.digital Russell wrote:

If you’re going to the trouble of putting Adobe RGB into your workflow, thus choking off a huge range of available software, why not go all the
way
and use a well-designed colorspace like ProPhoto RGB?

Reading Scott Kelby, the first thing he suggests is replacing sRGB by Adobe
RGB 98.
Most photographer, I thought would shy away from sRGB.
When I bought my Canon XT, I asked about that choice and was told if you use
Adobe Photoshop, it’s better to choose Adobe RGB.
Why introduce ProPhoto RGB?
Could you please enlighten me?

Take a look at this
http://www.luminous-landscape.com/cgi-bin/forum/ikonboard.cg i?act=ST;f=5;t=1604
Sorry Lester.
To take a look I had to register, which I did.
Then it wouldn’t remember my member’s name. If I wanted to change the name, it would state that my e-mail address was already in with another name. I guess it’s not my day.
Marcel
J
johnastovall
Sep 11, 2005
On Sun, 11 Sep 2005 17:36:53 -0400, "Celcius" wrote:

"Lester Wareham" wrote in message
"Celcius" wrote in message
"Bill Tuthill" wrote in message
In rec.photo.digital Russell wrote:

If you’re going to the trouble of putting Adobe RGB into your workflow, thus choking off a huge range of available software, why not go all the
way
and use a well-designed colorspace like ProPhoto RGB?

Reading Scott Kelby, the first thing he suggests is replacing sRGB by Adobe
RGB 98.
Most photographer, I thought would shy away from sRGB.
When I bought my Canon XT, I asked about that choice and was told if you use
Adobe Photoshop, it’s better to choose Adobe RGB.
Why introduce ProPhoto RGB?
Could you please enlighten me?

Take a look at this
http://www.luminous-landscape.com/cgi-bin/forum/ikonboard.cg i?act=ST;f=5;t=1604
Sorry Lester.
To take a look I had to register, which I did.
Then it wouldn’t remember my member’s name. If I wanted to change the name, it would state that my e-mail address was already in with another name. I guess it’s not my day.
Marcel

Here’s why and you don’t have to register. Like I said earlier larger color Gamut.

http://www.luminous-landscape.com/tutorials/prophoto-rgb.sht ml

http://www.naturephotographers.net/articles1203/mh1203-1.htm l

http://www.outbackphoto.com/color_management/cm_06/essay.htm l

********************************************************

"…bray a fool in a morter with wheat,
yet shall not his folly be beaten out of him;.."

"The Marriage of Heaven and Hell"
William Blake
M
Marcel
Sep 11, 2005
"John A. Stovall" wrote in message
Responding to "Celcius"

Here’s why and you don’t have to register. Like I said earlier larger color Gamut.

http://www.luminous-landscape.com/tutorials/prophoto-rgb.sht ml
http://www.naturephotographers.net/articles1203/mh1203-1.htm l
http://www.outbackphoto.com/color_management/cm_06/essay.htm l

Thank you John.
I will read and ponder upon this information.
To tell you the truth, it’s the very first time I hear about this. Cheers,
Marcel
BT
Bill Tuthill
Sep 12, 2005
In rec.photo.digital Celcius wrote:
If you’re going to the trouble of putting Adobe RGB into your workflow, thus choking off a range of available software, why not go all the way and use a well-designed colorspace like ProPhoto RGB?
Reading Scott Kelby, the first thing he suggests is replacing sRGB by Adobe RGB 98.
Most photographer, I thought would shy away from sRGB.
When I bought my Canon XT, I asked about that choice and was told if you use Adobe Photoshop, it’s better to choose Adobe RGB. Why introduce ProPhoto RGB?
Could you please enlighten me?

Adobe RGB was designed to contain both RGB (monitor) colorspace(s) and CMYK colorspaces for offset printing.

If you don’t do offset printing, the CMYK colorspaces are not useful.

So using Adobe RGB complicates your workflow, introduces colorspace conversion problems, and doesn’t improve your results for web images or for images printed on Fuji Frontier, an SRGB-compliant device. Possibly Adobe RGB will allow you to make better inkjet prints.

ProPhoto RGB can increase color gamut and especially dynamic range, an area where digital photos often suffer.
LW
Lester Wareham
Sep 12, 2005
"Celcius" wrote in message
"Lester Wareham" wrote in message
"Celcius" wrote in message
"Bill Tuthill" wrote in message
In rec.photo.digital Russell wrote:

If you’re going to the trouble of putting Adobe RGB into your workflow,
thus choking off a huge range of available software, why not go all the
way
and use a well-designed colorspace like ProPhoto RGB?

Reading Scott Kelby, the first thing he suggests is replacing sRGB by Adobe
RGB 98.
Most photographer, I thought would shy away from sRGB.
When I bought my Canon XT, I asked about that choice and was told if you
use
Adobe Photoshop, it’s better to choose Adobe RGB.
Why introduce ProPhoto RGB?
Could you please enlighten me?

Take a look at this
http://www.luminous-landscape.com/cgi-bin/forum/ikonboard.cg i?act=ST;f=5;t=1604
Sorry Lester.
To take a look I had to register, which I did.
Then it wouldn’t remember my member’s name. If I wanted to change the name,
it would state that my e-mail address was already in with another name. I guess it’s not my day.
Marcel

Never mind John has put some of the links in.

If you are interested there is quite a lengthy discussion on the pros and cons in the link I sent you.

Its a good forum so it might be worth persisting.
..
H
Hecate
Sep 12, 2005
On 12 Sep 2005 11:11:16 -0700, Bill Tuthill wrote:

In rec.photo.digital Celcius wrote:
If you’re going to the trouble of putting Adobe RGB into your workflow, thus choking off a range of available software, why not go all the way and use a well-designed colorspace like ProPhoto RGB?
Reading Scott Kelby, the first thing he suggests is replacing sRGB by Adobe RGB 98.
Most photographer, I thought would shy away from sRGB.
When I bought my Canon XT, I asked about that choice and was told if you use Adobe Photoshop, it’s better to choose Adobe RGB. Why introduce ProPhoto RGB?
Could you please enlighten me?

Adobe RGB was designed to contain both RGB (monitor) colorspace(s) and CMYK colorspaces for offset printing.

If you don’t do offset printing, the CMYK colorspaces are not useful.
Actually, that should read: If you don’t do printing. Printers print using CMYK, regardless of whether the files they get are RGB or CMYK.

So, if you don’t do printing, ProPhoto RGB is fine. If you do…



Hecate – The Real One

Fashion: Buying things you don’t need, with money
you don’t have, to impress people you don’t like…
JB
John Bean
Sep 13, 2005
On Tue, 13 Sep 2005 00:58:56 +0100, Hecate
wrote:

On 12 Sep 2005 11:11:16 -0700, Bill Tuthill wrote:

In rec.photo.digital Celcius wrote:
If you’re going to the trouble of putting Adobe RGB into your workflow, thus choking off a range of available software, why not go all the way and use a well-designed colorspace like ProPhoto RGB?
Reading Scott Kelby, the first thing he suggests is replacing sRGB by Adobe RGB 98.
Most photographer, I thought would shy away from sRGB.
When I bought my Canon XT, I asked about that choice and was told if you use Adobe Photoshop, it’s better to choose Adobe RGB. Why introduce ProPhoto RGB?
Could you please enlighten me?

Adobe RGB was designed to contain both RGB (monitor) colorspace(s) and CMYK colorspaces for offset printing.

If you don’t do offset printing, the CMYK colorspaces are not useful.
Actually, that should read: If you don’t do printing. Printers print using CMYK, regardless of whether the files they get are RGB or CMYK.
So, if you don’t do printing, ProPhoto RGB is fine. If you do…

That makes no sense. Adobe RGB is preferred for printing *only* because it’s a larger space than sRGB (which will clip some CMYK colours). ProPhoto RGB is bigger still and will almost certainly not clip the printing gamut.

So why do you believe ProPhoto RGB is unsuitable for
printing?


Regards

John Bean
H
Hecate
Sep 14, 2005
On Tue, 13 Sep 2005 09:00:09 +0100, John Bean
wrote:

Actually, that should read: If you don’t do printing. Printers print using CMYK, regardless of whether the files they get are RGB or CMYK.
So, if you don’t do printing, ProPhoto RGB is fine. If you do…

That makes no sense. Adobe RGB is preferred for printing *only* because it’s a larger space than sRGB (which will clip some CMYK colours). ProPhoto RGB is bigger still and will almost certainly not clip the printing gamut.

So why do you believe ProPhoto RGB is unsuitable for
printing?

Actually, it makes perfect sense if you realise what each colour space encompasses. Look at the 3D colour space maps which show the actual colour spaces covered. If you compare the three you mention, sRGB is useless except for web images because it narrows the space and at the same time has large areas of clipping when printing because it doesn’t match the CMYK colour space at all well. OTOH, ProPhotoRGB has a wider colour space than Adobe RGB *but* it also does not match the CMYK colour space very well. AdobeRGB, OTOH, matches the CMYK colour space more closely and will result in less clipping (i.e. less out of gamut colours) when printing – especially in the yellows and greens which landscape photographers, for example, will find important.

It’s all very well having a wider colour space such as ProPhoto, but it’s not much use if those colours disappear as soon as you print.



Hecate – The Real One

Fashion: Buying things you don’t need, with money
you don’t have, to impress people you don’t like…
DN
dj_nme
Sep 14, 2005
John Bean wrote:
<snip>
So why do you believe ProPhoto RGB is unsuitable for
printing?

Ther is a chance of posterisation of tones that are reproducable on a CYMK printer.
Perhaps the effect will not be as vile as converting an image from VGA to CGA display colour gamut, but there could be some un-expected banding or colour splotches caused by the printing software converting from a larger colour space to a smaller colour space and it just not knowing what to do.

It is also assuming that the origianl image was taken with a digital camera or scanner that can save in the ProPhoto RGB colour space. To the best of my knowledge, none exist (at this point in time) and so the colour workflow may look something like this: image taken as RAW file in camera, converted to a Adobe RGB by the RAW software, opened in a graphics program and then converted to ProPhoto RGB and saved and printed.
Going from smaller to larger colour space wont have a chance to posterise, because all of the info from the smaller fits into the larger colour space.
Going the other way (for example printing out an image), has the potential to cause banding/posterisation because more colour info has to be squashed back onto a smaller colour space which just can’t handle the extra info.
This might be especially true if the colours have been changed (eg colour balancing) between opening the Adobe RGB image and saving as a ProPhoto RGB image.

It may not happen in real life, try it and see.
JB
John Bean
Sep 14, 2005
On Wed, 14 Sep 2005 02:15:01 +0100, Hecate
wrote:

On Tue, 13 Sep 2005 09:00:09 +0100, John Bean
wrote:
So why do you believe ProPhoto RGB is unsuitable for
printing?

Actually, it makes perfect sense if you realise what each colour space encompasses. Look at the 3D colour space maps which show the actual colour spaces covered. If you compare the three you mention, sRGB is useless except for web images because it narrows the space and at the same time has large areas of clipping when printing because it doesn’t match the CMYK colour space at all well. OTOH, ProPhotoRGB has a wider colour space than Adobe RGB *but* it also does not match the CMYK colour space very well. AdobeRGB, OTOH, matches the CMYK colour space more closely and will result in less clipping (i.e. less out of gamut colours) when printing – especially in the yellows and greens which landscape photographers, for example, will find important.

I’ve looked at the models and I fail to see any significant clipping of ProPhoto that doesn’t occur with Adobe RGB, that was my point.

It’s all very well having a wider colour space such as ProPhoto, but it’s not much use if those colours disappear as soon as you print.

Not so. The wider space can be mapped into the smaller space such that the colours don’t simply clip, but are
progressively moved to fit. This allows subtle tone
variations to still be visible at the expense of absolute colour accuracy.

If using a raw file as a source ProPhoto retains far more of the colour the camera delivers than a smaller space can
hold, and it’s far better to retain as much information for as long as possible in the subsequent processing, rather than choosing a small colour space right at the beginning.


Regards

John Bean
JB
John Bean
Sep 14, 2005
On 13 Sep 2005 18:21:40 -0700, wrote:

John Bean wrote:
<snip>
So why do you believe ProPhoto RGB is unsuitable for
printing?

It is also assuming that the origianl image was taken with a digital camera or scanner that can save in the ProPhoto RGB colour space.

Of course that’s what I was assuming 😉

To the best of my knowledge, none exist (at this point in time)

You need to do more research. I use Photoshop and Adobe
Camera Raw (ACR), and all my raw files are converted to
16-bit ProPhoto RGB by ACR as they are opened in Photoshop.


Regards

John Bean
LN
Linda Nieuwenstein
Sep 14, 2005
wrote…
John Bean wrote:
<snip>
So why do you believe ProPhoto RGB is unsuitable for
printing?

Ther is a chance of posterisation of tones that are reproducable on a CYMK printer.
Posterization will only occur if the printer does not support the gamut of the color space being utilized, and therefore has to convert to a more narrow gamut, using its more limited choice of color to fill the holes where color outside its gamut exists. Most inkjet printers are limited to the sRGB space, a smaller gamut than aRGB’s. You could can get a degree of posturization during the conversion from aRGB to the printer’s sRGB ability. The concern is far more relivant to an average home user who has a consumer level inkjet printer than it would be to commercial printers (print press businesses) because they purchase the commercial equipment that supports wider gamuts.

Take care,
Linda
H
Hecate
Sep 15, 2005
On Wed, 14 Sep 2005 10:00:05 +0100, John Bean
wrote:

On Wed, 14 Sep 2005 02:15:01 +0100, Hecate
wrote:

On Tue, 13 Sep 2005 09:00:09 +0100, John Bean
wrote:
So why do you believe ProPhoto RGB is unsuitable for
printing?

Actually, it makes perfect sense if you realise what each colour space encompasses. Look at the 3D colour space maps which show the actual colour spaces covered. If you compare the three you mention, sRGB is useless except for web images because it narrows the space and at the same time has large areas of clipping when printing because it doesn’t match the CMYK colour space at all well. OTOH, ProPhotoRGB has a wider colour space than Adobe RGB *but* it also does not match the CMYK colour space very well. AdobeRGB, OTOH, matches the CMYK colour space more closely and will result in less clipping (i.e. less out of gamut colours) when printing – especially in the yellows and greens which landscape photographers, for example, will find important.

I’ve looked at the models and I fail to see any significant clipping of ProPhoto that doesn’t occur with Adobe RGB, that was my point.

It’s all very well having a wider colour space such as ProPhoto, but it’s not much use if those colours disappear as soon as you print.

Not so. The wider space can be mapped into the smaller space such that the colours don’t simply clip, but are
progressively moved to fit. This allows subtle tone
variations to still be visible at the expense of absolute colour accuracy.

If using a raw file as a source ProPhoto retains far more of the colour the camera delivers than a smaller space can
hold, and it’s far better to retain as much information for as long as possible in the subsequent processing, rather than choosing a small colour space right at the beginning.

Well, you do what you need to do, and I’ll do what I need to do as you obviously think that wider is better. Maybe you’d like to try WideRGB?



Hecate – The Real One

Fashion: Buying things you don’t need, with money
you don’t have, to impress people you don’t like…
DN
dj_nme
Sep 15, 2005
John Bean wrote:
On 13 Sep 2005 18:21:40 -0700, wrote:

John Bean wrote:
<snip>
So why do you believe ProPhoto RGB is unsuitable for
printing?

It is also assuming that the origianl image was taken with a digital camera or scanner that can save in the ProPhoto RGB colour space.

Of course that’s what I was assuming 😉

Then you assuming the use of a camera that doesn’t (yet) exist. If you’ve got a camera or scanner that can natively record in prophoto, it can’t be a Canon, Contax, Sony, Nikon, Sigma, Pentax or Fuji because none of them make a camnera that can record a prophoto colour space image to it’s memory card.

To the best of my knowledge, none exist (at this point in time)

You need to do more research. I use Photoshop and Adobe
Camera Raw (ACR), and all my raw files are converted to
16-bit ProPhoto RGB by ACR as they are opened in Photoshop.

It isn’t your camera that makes the prophoto clour image, it is your software on your computer (from a raw image file that your camera _can_ make)
CD
Colin D
Sep 15, 2005
wrote:
John Bean wrote:
On 13 Sep 2005 18:21:40 -0700, wrote:

John Bean wrote:
<snip>
So why do you believe ProPhoto RGB is unsuitable for
printing?

It is also assuming that the origianl image was taken with a digital camera or scanner that can save in the ProPhoto RGB colour space.

Of course that’s what I was assuming 😉

Then you assuming the use of a camera that doesn’t (yet) exist. If you’ve got a camera or scanner that can natively record in prophoto, it can’t be a Canon, Contax, Sony, Nikon, Sigma, Pentax or Fuji because none of them make a camnera that can record a prophoto colour space image to it’s memory card.

To the best of my knowledge, none exist (at this point in time)

You need to do more research. I use Photoshop and Adobe
Camera Raw (ACR), and all my raw files are converted to
16-bit ProPhoto RGB by ACR as they are opened in Photoshop.

It isn’t your camera that makes the prophoto clour image, it is your software on your computer (from a raw image file that your camera _can_ make)

As I understand it all, your post-processing can *reduce* the gamut from the original, but expanding to a wider gamut from a narrower one is pointless. The original gamut is determined by the filter response curves in the camera, and if the camera can produce aRGB files, you can reduce them to sRGB, but expanding to prophotoRGB is pointless, since the colors that gamut can encompass do not exist in the original file.

Colin D.
JB
John Bean
Sep 15, 2005
On Thu, 15 Sep 2005 16:42:12 +1200, Colin D
wrote:

wrote:
John Bean wrote:
On 13 Sep 2005 18:21:40 -0700, wrote:

John Bean wrote:
<snip>
So why do you believe ProPhoto RGB is unsuitable for
printing?

It is also assuming that the origianl image was taken with a digital camera or scanner that can save in the ProPhoto RGB colour space.

Of course that’s what I was assuming 😉

Then you assuming the use of a camera that doesn’t (yet) exist. If you’ve got a camera or scanner that can natively record in prophoto, it can’t be a Canon, Contax, Sony, Nikon, Sigma, Pentax or Fuji because none of them make a camnera that can record a prophoto colour space image to it’s memory card.

To the best of my knowledge, none exist (at this point in time)

You need to do more research. I use Photoshop and Adobe
Camera Raw (ACR), and all my raw files are converted to
16-bit ProPhoto RGB by ACR as they are opened in Photoshop.

It isn’t your camera that makes the prophoto clour image, it is your software on your computer (from a raw image file that your camera _can_ make)

As I understand it all, your post-processing can *reduce* the gamut from the original, but expanding to a wider gamut from a narrower one is pointless. The original gamut is determined by the filter response curves in the camera, and if the camera can produce aRGB files, you can reduce them to sRGB, but expanding to prophotoRGB is pointless, since the colors that gamut can encompass do not exist in the original file.

Raw files are unprocessed in the camera, that’s why they’re raw…

Only later when the raw files are converted to RGB is a
colour space chosen, so there’s no "expansion" at all by using ProPhoto, just less clipping than would occur if using either of the two much smaller spaces.


Regards

John Bean
CD
Colin D
Sep 16, 2005
John Bean wrote:
On Thu, 15 Sep 2005 16:42:12 +1200, Colin D
wrote:

wrote:
John Bean wrote:
On 13 Sep 2005 18:21:40 -0700, wrote:

John Bean wrote:
<snip>
So why do you believe ProPhoto RGB is unsuitable for
printing?

It is also assuming that the origianl image was taken with a digital camera or scanner that can save in the ProPhoto RGB colour space.

Of course that’s what I was assuming 😉

Then you assuming the use of a camera that doesn’t (yet) exist. If you’ve got a camera or scanner that can natively record in prophoto, it can’t be a Canon, Contax, Sony, Nikon, Sigma, Pentax or Fuji because none of them make a camnera that can record a prophoto colour space image to it’s memory card.

To the best of my knowledge, none exist (at this point in time)

You need to do more research. I use Photoshop and Adobe
Camera Raw (ACR), and all my raw files are converted to
16-bit ProPhoto RGB by ACR as they are opened in Photoshop.

It isn’t your camera that makes the prophoto clour image, it is your software on your computer (from a raw image file that your camera _can_ make)

As I understand it all, your post-processing can *reduce* the gamut from the original, but expanding to a wider gamut from a narrower one is pointless. The original gamut is determined by the filter response curves in the camera, and if the camera can produce aRGB files, you can reduce them to sRGB, but expanding to prophotoRGB is pointless, since the colors that gamut can encompass do not exist in the original file.

Raw files are unprocessed in the camera, that’s why they’re raw…

Only later when the raw files are converted to RGB is a
colour space chosen, so there’s no "expansion" at all by using ProPhoto, just less clipping than would occur if using either of the two much smaller spaces.
Agreed, but if the color space provided by the RGB filters in the camera did not provide the colors to fill the chosen colorspace, then using that space or gamut is pointless.

Consider a camera that has blue and green filters, but no red filter. The resulting image would have no red component other than a possible reduced response from the slope of the green filter, which would then be rendered as green. Such an image could not fill even a sRGB gamut, let alone a wider one. If the filters in camera cannot supply all the colors in a given color space, then it’s pointless using that space. or so it seems to me.

Colin D.
JB
John Bean
Sep 16, 2005
On Fri, 16 Sep 2005 21:18:55 +1200, Colin D
wrote:

John Bean wrote:
Only later when the raw files are converted to RGB is a
colour space chosen, so there’s no "expansion" at all by using ProPhoto, just less clipping than would occur if using either of the two much smaller spaces.
Agreed, but if the color space provided by the RGB filters in the camera did not provide the colors to fill the chosen colorspace, then using that space or gamut is pointless.

But not harmful either. Someone suggested that ProPhoto
somehow is "worse" than Adobe RGB, and that’s simply not true.

Consider a camera that has blue and green filters, but no red filter.

No point. Lets consider reality instead, and the colour
gamut of any Bayer sensor doesn’t fit in either sRGB or
Adobe RGB.

Less clipping occurs if you use ProPhoto RGB when converting raw images. If you’re unconvinced then a lot of expert
opinion says this is so. Perhaps you haven’t read Bruce
Fraser on this subject, to name just one.


Regards

John Bean
MR
Mike Russell
Sep 16, 2005
From: "John Bean"

wrote:

John Bean wrote:
Only later when the raw files are converted to RGB is a
colour space chosen, so there’s no "expansion" at all by using ProPhoto, just less clipping than would occur if using either of the two much smaller spaces.
Agreed, but if the color space provided by the RGB filters in the camera did not provide the colors to fill the chosen colorspace, then using that space or gamut is pointless.

But not harmful either. Someone suggested that ProPhoto
somehow is "worse" than Adobe RGB, and that’s simply not true.

Not to single out John, but I think beginners should be very careful about separating wheat from chaff in this particular thread.

The "expansion" of ProPhoto RGB can have serious consequences, particularly for 8 bit per channel images. ProPhoto RGB, as with any very wide gamut space, can result in unacceptable noise, and posterization of the image. In 16 or 32 bit per channel this is not the case, however not all of us will choose to work at that bit depth, particularly when no clear advantage to working in ProPhoto RGB has been demonstrated.

Because of it’s immense gamut, ProPhoto RGB also produces artifacts, in some situations, when converting to Lab. Try it yourself – create a white to blue gradient and convert it from ProPhoto RGB to Lab – see the black band at about the three quartertone? This occurs in 8 as well as 16 bit images.

Consider a camera that has blue and green filters, but no red filter.

No point. Lets consider reality instead, and the colour
gamut of any Bayer sensor doesn’t fit in either sRGB or
Adobe RGB.

I’m not so sure. Adobe RGB is actually quite large, for an RGB space, and it may well be sufficient for many of the sensors out there.

Less clipping occurs if you use ProPhoto RGB when converting raw images. If you’re unconvinced then a lot of expert
opinion says this is so. Perhaps you haven’t read Bruce
Fraser on this subject, to name just one.

Fraser is a great guy, and I have read his books, but why is it necessary to appeal to authority?

Seeing is believing. If ProPhoto RGB has a decisive advantage, it should be easy to come up with a photograph in which use of ProPhoto RGB results in a markedly better image – printout, screen, what have you, than the same image exported in Adobe RGB or sRGB.

Again, not to put John on the spot here, but in all seriousness, I’m genuinely interested. Does anyone have such an image? For example, a raw file where the ProPhotoRGB image contains detail or color that goes away when the same image is exported as Adobe RGB?

I suspect I will wait a long time before being presented with such an image, so I will say this: Given the great number of new ideas that are being tried right now, it’s a safe bet that many of them are simply wrong. Lack of an image demonstrating a particular principle is a good indication that that principle is not going to pan out, in the long run.

Until a photograph that demonstrates the superiority of ProPhoto RGB appears, I think those of us who work in Adobe RGB and sRGB may rest easily, whatever the "authorities" may say.

Indeed, even if one or two images do turn up, I believe it is the case that for the vast majority of photos, ProPhoto is overkill, and 16 bits per channel is overkill. Toolmaker that I am, I say this with respect for those who take excellent photographs, and who believe otherwise. —
Mike Russell
www.curvemeister.com
H
Hecate
Sep 18, 2005
On Fri, 16 Sep 2005 22:29:18 GMT, "Mike Russell" wrote:

From: "John Bean"

wrote:

John Bean wrote:
Only later when the raw files are converted to RGB is a
colour space chosen, so there’s no "expansion" at all by using ProPhoto, just less clipping than would occur if using either of the two much smaller spaces.
Agreed, but if the color space provided by the RGB filters in the camera did not provide the colors to fill the chosen colorspace, then using that space or gamut is pointless.

But not harmful either. Someone suggested that ProPhoto
somehow is "worse" than Adobe RGB, and that’s simply not true.

Not to single out John, but I think beginners should be very careful about separating wheat from chaff in this particular thread.

The "expansion" of ProPhoto RGB can have serious consequences, particularly for 8 bit per channel images. ProPhoto RGB, as with any very wide gamut space, can result in unacceptable noise, and posterization of the image. In 16 or 32 bit per channel this is not the case, however not all of us will choose to work at that bit depth, particularly when no clear advantage to working in ProPhoto RGB has been demonstrated.

And some disadvantages, as I’ve already tried to point out to him.

Because of it’s immense gamut, ProPhoto RGB also produces artifacts, in some situations, when converting to Lab. Try it yourself – create a white to blue gradient and convert it from ProPhoto RGB to Lab – see the black band at about the three quartertone? This occurs in 8 as well as 16 bit images.
Consider a camera that has blue and green filters, but no red filter.

No point. Lets consider reality instead, and the colour
gamut of any Bayer sensor doesn’t fit in either sRGB or
Adobe RGB.

I’m not so sure. Adobe RGB is actually quite large, for an RGB space, and it may well be sufficient for many of the sensors out there.

And I find it at least interesting that semi-pro and pro cameras usually provide AdobeRGB. 🙂

Less clipping occurs if you use ProPhoto RGB when converting raw images. If you’re unconvinced then a lot of expert
opinion says this is so. Perhaps you haven’t read Bruce
Fraser on this subject, to name just one.

Fraser is a great guy, and I have read his books, but why is it necessary to appeal to authority?

Because, I suspect, he thinks that he’s read the book and understood it. I’ve read the book too and he hasn’t. He’s making the assumption that what Fraser says applies whatever the situation whereas Fraser makes clear that isn’t the case.

And anyway, just because Fraser says something doesn’t make him 100% right all the time. Like any other human, he has his biases. OTOH, I usually find him pretty much on the money 🙂

Seeing is believing. If ProPhoto RGB has a decisive advantage, it should be easy to come up with a photograph in which use of ProPhoto RGB results in a markedly better image – printout, screen, what have you, than the same image exported in Adobe RGB or sRGB.
<snip>
Indeed, even if one or two images do turn up, I believe it is the case that for the vast majority of photos, ProPhoto is overkill, and 16 bits per channel is overkill. Toolmaker that I am, I say this with respect for those who take excellent photographs, and who believe otherwise.

Precisely. Though, of course, as I’ve done before, I’ll have to disagree about the 16bit comment 🙂



Hecate – The Real One

Fashion: Buying things you don’t need, with money
you don’t have, to impress people you don’t like…
JB
John Bean
Sep 18, 2005
On Fri, 16 Sep 2005 22:29:18 GMT, "Mike Russell" wrote:
Less clipping occurs if you use ProPhoto RGB when converting raw images. If you’re unconvinced then a lot of expert
opinion says this is so. Perhaps you haven’t read Bruce
Fraser on this subject, to name just one.

Fraser is a great guy, and I have read his books, but why is it necessary to appeal to authority?

It’s not an appeal Mike, it’s a reference to an accepted authority – which I’m clearly not – who offers a point of view similar to the one I was making. Do you never quote such references?


Regards

John Bean
MR
Mike Russell
Sep 18, 2005
"John Bean" wrote in message
On Fri, 16 Sep 2005 22:29:18 GMT, "Mike Russell" wrote:
Less clipping occurs if you use ProPhoto RGB when converting raw images. If you’re unconvinced then a lot of expert
opinion says this is so. Perhaps you haven’t read Bruce
Fraser on this subject, to name just one.

Fraser is a great guy, and I have read his books, but why is it necessary to
appeal to authority?

It’s not an appeal Mike, it’s a reference to an accepted authority – which I’m clearly not – who offers a point of view similar to the one I was making. Do you never quote such references?

I find experiments and examples much more convincing than simply telling someone that a third person feels a certain way.

But, for the moment, I’ll break that pattern, and accept Bruce as an authority. Here goes:

I’m certain – enough to lay money on it – that Bruce has never provided, in all his books, articles, and posts, a raw image that does demonstrably better in ProPhoto RGB than in Adobe RGB.

If you believe he has, please point me to the image. But if you agree that Bruce has not provided such an example, I suggest that this as authoritative evidence, by your own lights, that no such image exists. —

Mike Russell
www.curvemeister.com
JB
John Bean
Sep 18, 2005
Mike, you sound like a zealot who has something to prove, especially in your disagreements with Bruce Fraser. I’m not playing your game.

FWIW, I agree entirely that it’s a bad idea to switch
between Lab and RGB when using very large RGB spaces, and I entirely disagree that 16-bit is an overkill. With that in mind, and the fact that at the start of the thread I stated I work with 16-bit ProPhoto RGB conversions from raw, I have seen no evidence to indicate that this space is in any way harmful to the data in the way that was being suggested.

I’ve been working this way since before the time that Fraser started recommending ProPhoto RGB and my comments in this thread have been based on my personal experience, not by "misunderstanding" Fraser’s books as seems to have been suggested (not by you). Each to his own I guess, but
condescention and "prove it" challenges don’t strengthen your argument one little bit.


Regards

John Bean
MR
Mike Russell
Sep 18, 2005
"John Bean" wrote in message
Mike, you sound like a zealot who has something to prove, especially in your disagreements with Bruce Fraser. I’m not playing your game.

FWIW, I agree entirely that it’s a bad idea to switch
between Lab and RGB when using very large RGB spaces, and I entirely disagree that 16-bit is an overkill. With that in mind, and the fact that at the start of the thread I stated I work with 16-bit ProPhoto RGB conversions from raw, I have seen no evidence to indicate that this space is in any way harmful to the data in the way that was being suggested.
I’ve been working this way since before the time that Fraser started recommending ProPhoto RGB and my comments in this thread have been based on my personal experience, not by "misunderstanding" Fraser’s books as seems to have been suggested (not by you). Each to his own I guess, but
condescention and "prove it" challenges don’t strengthen your argument one little bit.

It should be simple, then, to provide an example image that benefits from the ProPhoto 16 bit treatment..


Mike Russell
www.curvemeister.com
R
rfischer
Sep 18, 2005
Mike Russell wrote:
"John Bean" wrote in message
Mike, you sound like a zealot who has something to prove, especially in your disagreements with Bruce Fraser. I’m not playing your game.

FWIW, I agree entirely that it’s a bad idea to switch
between Lab and RGB when using very large RGB spaces, and I entirely disagree that 16-bit is an overkill. With that in mind, and the fact that at the start of the thread I stated I work with 16-bit ProPhoto RGB conversions from raw, I have seen no evidence to indicate that this space is in any way harmful to the data in the way that was being suggested.
I’ve been working this way since before the time that Fraser started recommending ProPhoto RGB and my comments in this thread have been based on my personal experience, not by "misunderstanding" Fraser’s books as seems to have been suggested (not by you). Each to his own I guess, but
condescention and "prove it" challenges don’t strengthen your argument one little bit.

It should be simple, then, to provide an example image that benefits from the ProPhoto 16 bit treatment..

Just to add fuel to the fire: Photoshop now has some support for 32-bit images. Why the hell would that ever be useful given that cameras capture only 12 to 16 bits? It’s handy when combining multiple images taken with different exposure settings. If you have a really high contrast scene it allows you to bracket the photo and then combine the images. You can then adjust the resulting 32-bit image without losing data at the extremes.


Ray Fischer
MR
Mike Russell
Sep 18, 2005
"Ray Fischer" wrote in message
….
Just to add fuel to the fire: Photoshop now has some support for 32-bit images. Why the hell would that ever be useful given that cameras capture only 12 to 16 bits?

This format is called HDR and was created in the course of work by people like Paul Devevec, and others, to represent luminance maps, which are used to create realistic lighting effects.
http://www.debevec.org/ .

There are situations requiring hibit data, and I’m familiar with those from my experience with medical imaging, which generates tremendous dynamic ranges for CT data. But this does not mean that every image, or even most images, benefit from being in hibit.

It’s handy when combining multiple
images taken with different exposure settings.

Yes, this is how it is done, and there are any number of interesting applications. I predict that some day, perhaps relatively soon, there will be a camera with firmware that creates an HDR image directly, and in the more distant future a detector that captures floating point images directly in hardware. Again, does this mean that every image captured today will benefit from this specialized ability? Obvioulsy not.

If you have a really
high contrast scene it allows you to bracket the photo and then combine the images. You can then adjust the resulting 32-bit image without losing data at the extremes.

I have seen some stunning shots resulting from combining several exposures, in terms of dynamic range, which you are talking about, and in terms of space with images taken at different focus planes. Here are the best examples I’ve seen from a technical and artistic standpoint: http://www.cambridgeincolour.com/

BTW – the same technique may be spread across time as well. When multi-exposure technique is applied to images taken at different times, you get the well-known time lapse shot. If the detector plane is shifted laterally, you can get rid of aliasing using multiple exposures. BTW – these are applications of concepts discussed in Robert Cook’s ground breaking paper on distributed ray tracing, published in the 1984 issue of Siggraph, and still bears reading today:

Clearly, each of these multi-exposure techniques can produce images that could not be produced in any other way. Does this mean every image should or can be done by combining multiple images? No, and I’m sure that neither you, nor any of the practitioners who create such photos would make this claim.

In this the creators of multi-exposure images differ from the small number of folks who believe that every high quality image requires ProPhoto/16, apparently doing so with not a single actual image to demonstrate that this is the case.


Mike Russell
www.curvemeister.com
BT
Bill Tuthill
Sep 18, 2005
In rec.photo.digital Mike Russell wrote:
I’m certain – enough to lay money on it – that Bruce has never provided, in all his books, articles, and posts, a raw image that does demonstrably better in ProPhoto RGB than in Adobe RGB.

If you believe he has, please point me to the image. But if you agree that Bruce has not provided such an example, I suggest that this as authoritative evidence, by your own lights, that no such image exists.

I have seen ProPhotoRGB images that showed more dynamic range than 8-bit images (can’t remember whether AdobeRGB or sRGB) but it’s likely that the greater dynamic range could have been produced just as easily in 8-bit using the Shadow/Highlight tool or something.

Theoretically, isn’t it worse to switch 8-bit images between AdobeRGB and sRGB, than to stick with one or the other? Doesn’t each switch result in conversion problems?
MR
Mike Russell
Sep 19, 2005
"Bill Tuthill" wrote in message
In rec.photo.digital Mike Russell
wrote:
I’m certain – enough to lay money on it – that Bruce has never provided, in
all his books, articles, and posts, a raw image that does demonstrably better in ProPhoto RGB than in Adobe RGB.

If you believe he has, please point me to the image. But if you agree that
Bruce has not provided such an example, I suggest that this as authoritative
evidence, by your own lights, that no such image exists.

I have seen ProPhotoRGB images that showed more dynamic range than 8-bit images (can’t remember whether AdobeRGB or sRGB) but it’s likely that the greater dynamic range could have been produced just as easily in 8-bit using the Shadow/Highlight tool or something.

Hi Bill,

I’ll bet you two adult sized life jackets that you’re remembering wrong, and this was an issue with 16 bit versus 8 bit, and not ProPhoto. ProPhoto has a larger color gamut, but it is a gamma 2.2 space with the same dynamic range as Adobe RGB.

Theoretically, isn’t it worse to switch 8-bit images between AdobeRGB and sRGB, than to stick with one or the other? Doesn’t each switch result in conversion problems?

Theoretically, yes, and I certainly wouldn’t convert back and forth for no reason, but the conversion problems are negligible for operations like saving for web.


Mike Russell
www.curvemeister.com
MR
Mike Russell
Sep 19, 2005
I was mistaken. ProPhoto is gamma 1.8, and Adobe RGB is 2.2. This can make a difference in shadow detail for certain images, with a slight advantage going to ProPhoto.

But Bill still has to find the image to get his two life jacket reward 🙂 —
Mike Russell
www.curvemeister.com
BT
Bill Tuthill
Sep 19, 2005
In rec.photo.digital Mike Russell wrote:
I’ll bet you two adult sized life jackets that you’re remembering wrong, and this was an issue with 16 bit versus 8 bit, and not ProPhoto. ProPhoto has a larger color gamut, but it is a gamma 2.2 space with the same dynamic range as Adobe RGB.

You’re right that it might have been entirely 16 bit versus 8 bit, but I’m certain it was a ProPhotoRGB versus some old-style colorspace. Unfortunately the images have gone off the Web, otherwise I would have provided URL.

Off topic: The new MTI Big Buoy is a nice life jacket!

As I alluded to, the new Shadow/Highlight tool in Photoshop CS 8 seems to do an excellent job of increasing the visible dynamic range. There are other ways of doing this, but Shadow/Highlight seems easy.

Theoretically, isn’t it worse to switch 8-bit images between AdobeRGB and sRGB, than to stick with one or the other? Doesn’t each switch result in conversion problems?
Theoretically, yes, and I certainly wouldn’t convert back and forth for no reason, but the conversion problems are negligible for operations like saving for web.

Thanks.

Does alt.graphics.photoshop have a higher signal to noise ratio than the comp.graphics.apps.photoshop newsgroup?
Last time I checked the latter was high-volume and booooooooring.
D
davem
Sep 19, 2005
Bill Tuthill writes:
In rec.photo.digital Mike Russell wrote:
I’ll bet you two adult sized life jackets that you’re remembering wrong, and this was an issue with 16 bit versus 8 bit, and not ProPhoto. ProPhoto has a larger color gamut, but it is a gamma 2.2 space with the same dynamic range as Adobe RGB.

You’re right that it might have been entirely 16 bit versus 8 bit, but I’m certain it was a ProPhotoRGB versus some old-style colorspace. Unfortunately the images have gone off the Web, otherwise I would have provided URL.

You can’t really disentangle the two issues. If you use an 8 bit per pixel space, you want to pick an encoding that actually uses as many of the 256 available values as possible to avoid quantization errors. If sRGB contains all the colours you care about, then it’s better than Adobe RGB for that image because the possible colours are more densely spaced in colour space. If sRGB doesn’t work, but AdobeRGB does, then again it’s better than ProPhotoRGB if it gives denser sampling and better use of the limited number of pixel codes.

On the other hand, if you’re going to pay the cost of 16-bit channels anyway, then quantization error becomes a non-issue and you can pick the colour space using other criteria – such as making it larger than anything you’ll ever need for any image. But it’s the 16-bit channels that allow you to do that.

Dave
MR
Mike Russell
Sep 20, 2005
"Bill Tuthill" wrote in message
In rec.photo.digital Mike Russell
wrote:
I’ll bet you two adult sized life jackets that you’re remembering wrong, and this was an issue with 16 bit versus 8 bit, and not ProPhoto. ProPhoto
has a larger color gamut, but it is a gamma 2.2 space with the same dynamic
range as Adobe RGB.

You’re right that it might have been entirely 16 bit versus 8 bit, but I’m certain it was a ProPhotoRGB versus some old-style colorspace. Unfortunately
the images have gone off the Web, otherwise I would have provided URL.

Hi Tut,

ProPhoto is as old as any other color space. It used to be one of Kodak’s proprietary color spaces, dating back to at least 1998, when it was called ROM RGB and Master RGB. It was designed to contain the gamut of E6 films, and all films for that matter. It’s an input profile, intended to capture all the colors of a negative or positive film. Adobe RGB and sRGB are output oriented profiles, centered on colors that are useful for display purposes.

Think of ProPhoto as a giant 6 mpg Hummer, with custom springs so high you need to custom weld steps on the side of your car to get in and out. It’s an impedement, IMHO, for ordinary photographs to use it, and ProPhoto needs a 16 bit garage.

If you’re driving an sRGB Prius, or an Adobe RGB 98 Mustang, you get excellent transportaion, and can park in either the 8 bit or 16 bit garage.

Having a large garage does not mean you need a large car, nor are people with smaller cars necessarily in need of getting a larger one.

Off topic: The new MTI Big Buoy is a nice life jacket!

Wow – slick. Pockets too. I’m ashamed now of my bulky dayglo orange ones. OTOH, any life jacket is nice once you’re in the drink.

As I alluded to, the new Shadow/Highlight tool in Photoshop CS 8 seems to do an excellent job of increasing the visible dynamic range. There are other ways of doing this, but Shadow/Highlight seems easy.

S&H is definitely a hot tool, and I highly recommend that people get familiar with it. For those who haven’t upgraded to CS2, ts behavior may be duplicated by an action

Does alt.graphics.photoshop have a higher signal to noise ratio than the comp.graphics.apps.photoshop newsgroup?
Last time I checked the latter was high-volume and booooooooring.

LOL – yes. I shouldn’t laugh, but what can you do. It’s actually getting bad enough to degrade the usefulness of this group somewhat.

A good dose of block sender gets rid of most of it. I block nearly anyone who responds in kind to a thread cross posted to more than a couple of groups. Ignoring individual conversations is probably the best move since the names change around.

What’s new, sort of, about this trolling is that the person doing it poses as several different people who argue with one another in a way that tempts people to intervene, drawing more unsuspecting people into the fray. —

Mike Russell
www.curvemeister.com
BT
Bill Tuthill
Sep 20, 2005
In rec.photo.digital Mike Russell wrote:
ProPhoto is as old as any other color space. It used to be one of Kodak’s proprietary color spaces, dating back to at least 1998, when it was called ROM RGB and Master RGB. It was designed to contain the gamut of E6 films, and all films for that matter. It’s an input profile, intended to capture all the colors of a negative or positive film. Adobe RGB and sRGB are output oriented profiles, centered on colors useful for display purposes.

Interesting. I did not know all this, but had heard of Master RGB (and thought it was something different). Kodak had some great ideas, including the YCrCb compression method for original PhotoCD.

Think of ProPhoto as a giant 6 mpg Hummer, with custom springs so high you need to custom weld steps on the side of your car to get in and out. It’s an impedement, IMHO, for ordinary photographs to use it, and ProPhoto needs a 16 bit garage.

So can I use ProPhotoRGB to carry around soldiers without adequate armor against roadside bombs (improvised explosive devices) whilst generating handsome profits for General Motors?

I’ll check out alt.graphics.photoshop for a bit. I’m curious whether anybody there likes SaveForWeb. So far it hasn’t been discussed much. What does "Ducky" mean in the EXIF header?
MR
Mike Russell
Sep 21, 2005
Kodak had some great ideas, including
the YCrCb compression method for original PhotoCD.

There were a bunch of good ideas in PhotoCD. I think it got smothered because Kodak kept the PhotoCD creation software too close to the vest. This killed what might have otherwise been a good standard, and perhaps a juicy market. Not that it matters now, as the film digitizing market fades.

So can I use ProPhotoRGB to carry around soldiers without adequate armor against roadside bombs (improvised explosive devices) whilst generating handsome profits for General Motors?

LOL, and here’sWide Gamut RGB:
http://www.defensetech.org/archives/001612.html

I’ll check out alt.graphics.photoshop for a bit. I’m curious whether anybody there likes SaveForWeb. So far it hasn’t been discussed much.

Save For Web is widely used. For some reason it’s not discussed much in these
groups.

What does "Ducky" mean in the EXIF header?

Great questions today, Bill. I did a quick search – Adobe seems to sign it’s jpegs with the name "ducky" in the exif header, perhaps as a sort of hatched Easter egg. My private theory is that it’s to honor "Ducky Doolittle", the runner up for the Ole no Moir
BT
Bill Tuthill
Sep 21, 2005
In rec.photo.digital Mike Russell wrote:
LOL, and here’s Wide Gamut RGB:
http://www.defensetech.org/archives/001612.html

Despite wide gamut color, that thing is ugly looking!

Save For Web is widely used. For some reason it’s not discussed much in these groups.

Photoshop really isn’t a good tool for writing JPEG. Not only does SaveForWeb fail to warn about non-SRGB colorspace, it produces 2×2 chroma subsampling even at the highest (IJG 98) quality levels, which seems to me downright dumb. My tentative guideline would be to use 1×1 above IJG 85-90, and 2×2 below.

The old-style SaveAs JPEG dialog in Photoshop does not provide separate control over chroma subsampling, although maybe that’s not really necessary. At higher Q levels (7-12) it produces JPEG files that aren’t any better looking than IJG libraries do, but are larger, especially if default Preview isn’t turned off. At lower Q levels (1-4?) Photoshop does produce good looking JPEG compared to IJG, but I’m not sure this is an important thing to do: usually photographers want the highest quality possible, and webspace is much cheaper than it used to be.

JPEG Optimizer, free with PaintShopPro, might be better, but I have not yet investigated.

What does "Ducky" mean in the EXIF header?

Great questions today, Bill. I did a quick search – Adobe seems to sign its jpegs with the name "ducky" in the exif header, perhaps as a sort of hatched Easter egg. My private theory is that it’s to honor "Ducky Doolittle", the runner up for the Ole no Moiré image: http://www.deviantdesires.com/profiles/ducky/ducky.html

Interesting theory!

Seems that only SaveForWeb JPEG is enHeadered (is that a word?) Ducky.
H
Hecate
Sep 26, 2005
On 21 Sep 2005 13:22:46 -0700, Bill Tuthill wrote:

In rec.photo.digital Mike Russell wrote:
LOL, and here’s Wide Gamut RGB:
http://www.defensetech.org/archives/001612.html

Despite wide gamut color, that thing is ugly looking!

Save For Web is widely used. For some reason it’s not discussed much in these groups.

Photoshop really isn’t a good tool for writing JPEG. Not only does SaveForWeb fail to warn about non-SRGB colorspace, it produces 2×2 chroma subsampling even at the highest (IJG 98) quality levels, which seems to me downright dumb. My tentative guideline would be to use 1×1 above IJG 85-90, and 2×2 below.
Then again, some of us use Fireworks…. 🙂



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