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?
2005-06-20 18:55:47
#1
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?
http://www.cambridgeincolour.com/tutorials/sRGB-AdobeRGB1998 .htmWhilst 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.
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.
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?
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
In rec.photo.digital Russell wrote:way
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
and use a well-designed colorspace like ProPhoto RGB?
"Bill Tuthill" wrote in messageIn rec.photo.digital Russell wrote:way
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
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?
Real World Color Management: Industrial-Strength Production Techniques by Bruce Fraser, Chris Murphy, Fred Bunting
"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.
On Sat, 10 Sep 2005 18:49:40 -0300, "Linda Nieuwenstein" wrote:The RAW book is only required reading if you have digital files i.e. from a camera.
"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.
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.
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.
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
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
"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
On Sun, 11 Sep 2005 14:10:51 -0400, "Celcius" wrote:been
"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
say Imore "civil" in your response: "Go read...". You see, I've been into photography quite a while now and I'm sorry to
sorthadn't heard of ProPhoto RGB. Next time, pass me out. I don't need this
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/
"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.
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.
"Bill Tuthill" wrote in message
In rec.photo.digital Russell wrote:way
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
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?
"Celcius" wrote in messagehttp://www.luminous-landscape.com/cgi-bin/forum/ikonboard.cg i?act=ST;f=5;t=1604 Sorry Lester.
"Bill Tuthill" wrote in message
In rec.photo.digital Russell wrote:way
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
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
"Lester Wareham" wrote in message
"Celcius" wrote in messagehttp://www.luminous-landscape.com/cgi-bin/forum/ikonboard.cg i?act=ST;f=5;t=1604 Sorry Lester.
"Bill Tuthill" wrote in message
In rec.photo.digital Russell wrote:way
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
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
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
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
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?
"Lester Wareham" wrote in message
"Celcius" wrote in messagehttp://www.luminous-landscape.com/cgi-bin/forum/ikonboard.cg i?act=ST;f=5;t=1604 Sorry Lester.
"Bill Tuthill" wrote in message
In rec.photo.digital Russell wrote:way
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
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
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
In rec.photo.digital Celcius 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.
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.
On 12 Sep 2005 11:11:16 -0700, Bill Tuthill wrote:
In rec.photo.digital Celcius 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.
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, if you don't do printing, ProPhoto RGB is fine. If you do...
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?
So why do you believe ProPhoto RGB is unsuitable for
printing?
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.
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.
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.
To the best of my knowledge, none exist (at this point in time)
John Bean wrote: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.
<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.
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.
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.
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)
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.
On Thu, 15 Sep 2005 16:42:12 +1200, Colin DAgreed, 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.
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.
John Bean wrote:
Only later when the raw files are converted to RGB is aAgreed, 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.
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.
Consider a camera that has blue and green filters, but no red filter.
wrote:
John Bean wrote:
Only later when the raw files are converted to RGB is aAgreed, 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.
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.
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.
From: "John Bean"
wrote:
John Bean wrote:
Only later when the raw files are converted to RGB is aAgreed, 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.
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.
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.<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.
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?
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?
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.
"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.
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.
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?
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.
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.
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.
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.
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.
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.
Kodak had some great ideas, including
the YCrCb compression method for original PhotoCD.
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?
LOL, and here's Wide Gamut RGB:
http://www.defensetech.org/archives/001612.html
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 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
In rec.photo.digital Mike Russell wrote:Then again, some of us use Fireworks.... :)
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 2x2 chroma subsampling even at the highest (IJG 98) quality levels, which seems to me downright dumb. My tentative guideline would be to use 1x1 above IJG 85-90, and 2x2 below.