Way too accurate CRT gamma calibration targets available

Hi,

I've uploaded a set of unbearably accurate CRT gamma calibration charts: http://www.aim-dtp.net/aim/evaluation/gammaspace/index.htm Please have a look at them, I hope to hear if there is something to improve still.

The above is in form of CRT gamma evaluation but you can right-click the chart (of the system gamma-space that you are calibrating to) and make the chart as the background image of your desktop, there it will help AdobeGamma calibration enormously.

These chart are unbearably accurate since, with most consumer grade monitor, they make the small drift in the operation point of the monitor detectable. This drift can be rather rapid so that a change is detected within a hour or two or it can be very slow so that a change is detected only after some 8 to 24 hours of power on time.

Timo Autiokari http://www.aim-dtp.net

"Timo Autiokari" wrote in message

Hi,

I've uploaded a set of unbearably accurate CRT gamma calibration charts: http://www.aim-dtp.net/aim/evaluation/gammaspace/index.htm Please have a look at them, I hope to hear if there is something to

improve

still.

Yes you set the size of your naviagation frame properly.

The above is in form of CRT gamma evaluation but you can right-click the chart (of the system gamma-space that you are calibrating to) and make the chart as the background image of your desktop, there it will help AdobeGamma calibration enormously.

These chart are unbearably accurate

Now that is funny as shit! Why would anyone want to get them then if they are unbearable?

since, with most consumer grade
monitor, they make the small drift in the operation point of the monitor detectable. This drift can be rather rapid so that a change is detected within a hour or two or it can be very slow so that a change is detected only after some 8 to 24 hours of power on time.

You have been explaining us for a long time why Adobe is wrong and why you are right, Why our monitors are all displaying wrong colors and yours is not,
yet, I am still waiting to see ANYTHING you have created with your superior settings and deep understanding of profiles etc.
You are like a guy in a painting group telling people why the camel hair molecular structure is far superior to nylon.
Frankly, just between you and me, I don't give a shit.Abobe Gamma and my Epson are my friends and my work looks good.
I see you on a soap box with a sign around your neck saying : ASJUST YOUR MONITORS NOW! THE END IS NEAR

Stephan

I see you on a soap box with a sign around your neck saying : ASJUST YOUR MONITORS NOW! THE END IS NEAR

Stephan

How near?

"Timo Autiokari" wrote in message

Hi,

I've uploaded a set of unbearably accurate CRT gamma calibration charts: http://www.aim-dtp.net/aim/evaluation/gammaspace/index.htm Please have a look at them, I hope to hear if there is something to

improve

still.

Thanks for the contribution.

It might be helpful to note above and/or below the RGB/YMC "bars" (in a small font) with which gamma control it should be adjusted, and in what direction (e.g. +R or -G) to reach a balance.

Bart

Timo, your new site is BRILLIANT. My monitor has never been as well calibrated and for the first time in years I am getting accurate prints from my Epson. So from one user a heartfelt thanks.

Incidentally, I don't know who Stephan is but he seems both ill-mannered and juvenile. His language range is also a little lacking. Perhaps he will learn some original words one day, though sadly it seems to me that a whole generation of Americans seem to think that the word shit can be used to describe anything. The English language has so many wonderful words it is sad that they over-use this one, rather ugly one. But let's all hope that little Stephan learns some new ones soon, shall we? I'm sure when he does his doting parents will be so proud of him. He might then also get a girlfriend or boyfriend and go out more and bother all of us a little less.

Hang on though. Stephan is clearly very intelligent, or at least he seems to think so. I wonder.... is he really Stephen Hawking, Newton Professor of Physics at Cambridge, authir of a Brief History of Time. Silly of me not to see it straight away, and not to realize that the spelling of Stephan was not a first grade spelling mistake but a ruse to mislead us all.

"Timo Autiokari" wrote in message

Hi,

I've uploaded a set of unbearably accurate CRT gamma calibration charts: http://www.aim-dtp.net/aim/evaluation/gammaspace/index.htm Please have a look at them, I hope to hear if there is something to

improve

still.

The above is in form of CRT gamma evaluation but you can right-click the chart (of the system gamma-space that you are calibrating to) and make the chart as the background image of your desktop, there it will help AdobeGamma calibration enormously.

These chart are unbearably accurate since, with most consumer grade monitor, they make the small drift in the operation point of the monitor detectable. This drift can be rather rapid so that a change is detected within a hour or two or it can be very slow so that a change is detected only after some 8 to 24 hours of power on time.

Timo Autiokari http://www.aim-dtp.net

"

"JSH" wrote in message

Timo, your new site is BRILLIANT. My monitor has never been as well calibrated and for the first time in years I am getting accurate prints

from

my Epson. So from one user a heartfelt thanks.

Incidentally, I don't know who Stephan is but he seems both ill-mannered

and

juvenile. His language range is also a little lacking. Perhaps he will learn some original words one day, though sadly it seems to me that a

whole

generation of Americans seem to think that the word shit can be used to describe anything. The English language has so many wonderful words it is sad that they over-use this one, rather ugly one. But let's all hope that little Stephan learns some new ones soon, shall we? I'm sure when he does his doting parents will be so proud of him. He might then also get a girlfriend or boyfriend and go out more and bother all of us a little

less.

Hang on though. Stephan is clearly very intelligent, or at least he seems to think so. I wonder.... is he really Stephen Hawking, Newton Professor

of

Physics at Cambridge, authir of a Brief History of Time. Silly of me not

to

see it straight away, and not to realize that the spelling of Stephan was not a first grade spelling mistake but a ruse to mislead us all.

English happens to be my third language.
My real name is Stephane but since most people can't read properly they assume it is Stephanie because of the E at the end.
I read Hawking and you should use you spell check, he is an author, not an authir.
Thanks you for assuming I am so young, it is refreshing. There are a few more words I know and I would like whisper them in your hear but I let you guess them, more fun like that

Stephan

Timo Autiokari wrote:

I've uploaded a set of unbearably accurate CRT gamma calibration charts: http://www.aim-dtp.net/aim/evaluation/gammaspace/index.htm Please have a look at them, I hope to hear if there is something to improve still.

Timo, thanks for posting this. English not being your native tongue, you did a great job. Here are a few suggestions for improvement. The phrases in quotes are from your page.

"Set as Backgound" - in the Netscape browser, I believe that this should be Set as Wallpaper.

"On the left left" - change to At the far left?

"Top left" - Top right?

It would also be nice to have a "hard wired" chart that shows how a monitor is NOT properly calibrated. This chart will show how badly the far left, center and right sections look like.

My top and bottom right look pitch black and I have no idea what you meant by stripes. Yes, this tells me I need to adjust the monitor's black point setting.

My far left and center are almost gray. But compared to the chart's background, there is a VERY light, but observable, magenta cast in some areas. The cast is more visible at the shadow end of my right column of the far left pair. The cast is on all three channels at the center, but more on r and b. What does this mean? Should everything on the chart be without any cast at all?

My gamma is supposed to be at 2.2, and indeed that chart is the best when compared against charts of other gamma values. Perhaps this hint can be helpful.

JSH wrote:

Incidentally, I don't know who Stephan is but he seems both ill-mannered and juvenile. His language range is also a little lacking.

Stephan is just like many other posters here. Language is the least of his problems. These posters attack those who differ from what they believe in and what they know (or think they know). They are firm believers that the earth is flat and that evolution is heresy, and want to put away all those who dare to think otherwise.

wrote in message

JSH wrote:
They are firm believers that the earth is flat

Isn't it?

Hi,

In , wrote:

Thank you very much for the corrections! Uploaded them already.

It would also be nice to have a "hard wired" chart that shows how a monitor is NOT properly calibrated. This chart will show how badly the far left, center and right sections look like.

Aha, that sure would help to understand the charts more easily, hmmm it need to be an illustration, not having the dithers, I'll see what can be done, until then any chart with gamma-space that is way different than what the system is set to is good for this purpose.

My top and bottom right look pitch black and I have no idea what you meant by stripes.

Oh, they were stripes a long time ago, I've changed that now to say "pattern". There is similar kind of pattern (but in vertical) than what AdobeGamma shows, however the AdobeGamma "Brightness and Contrast" pattern is not correct, it outputs the very same RGB levels for the pattern no matter what "desired gamma" is selected, the fixed RGB values it outputs are good only for "desired value" of 2.5.

My far left and center are almost gray. But compared to the chart's background, there is a VERY light, but observable, magenta cast in some areas. The cast is more visible at the shadow end of my right column of the far left pair. The cast is on all three channels at the center, but more on r and b. What does this mean? Should everything on the chart be without any cast at all?

Yes, for perfect calibration the chart should appear as pure gray all over.

Now, the charts put the vision to an extremely sensitive state so a small cast (just discernible/detectable cast) is still an indication of good calibration. If you set the chart as the wallpaper you will most probably notice that the hue of the small cast changes as hours go by, this is due to the drift of the electronic components in the monitor.

There is a color cast or tonal range (gray) difference in case:

1) the tonal reproduction curve of the monitor (or the monitor path) does not follow the gamma law accurately (or if there is matrix or 3D look up table conversion such as a gamut or color-space conversion in the monitor path).

2) if the blackpoint of the monitor is not accurately set.

3) it is possible to get the cast also when using some existing profile as the starting point for AdobeGamma (profiles can be rather complex and AdobeGamma does not clean up everything in them). If the Description box in AdobeGamma says something else than "Adobe Monitor Settings" then AdobeGamma has used some profile as the starting point. The easiest way to start from the scratch is to zip compress all the profiles from the systems ICC profile directory (by *moving* to them the zip archive or just zipping first and then deleting the profiles) then when AdobeGamma is started the Description box will say "Adobe Monitor Settings" indicating that AdobeGamma has not read a profile in.

The cast is either in the dark end or in the highlight depending on how you adjust the gamma sliders in the AdobeGamma.

My gamma is supposed to be at 2.2, and indeed that chart is the best when compared against charts of other gamma values.

Blackpoint adjustment usually correct this.

Timo Autiokari http://www.aim-dtp.net

JSH wrote:

Timo, your new site is BRILLIANT. My monitor has never been as well calibrated and for the first time in years I am getting accurate prints from my Epson. So from one user a heartfelt thanks.

Fair enough. I've spend many an hour with Timo's gamma charts and recommend them to anyone who is interested in this issue.

--

Mike Russell
http://www.curvemeister.com
http://www.zocalo.net/~mgr
http://geigy.2y.net

Not sure how these are supposed to help with Adobe Gamma exactly. Maybe someone could explain it to me? I tried playing around and I think I've got my monitor pretty close to perfect, but it's curious that I have to enter a target gamma of 2.1 when making a profile in Adobe Gamma in order to achieve
2.2 according to the charts on Timo's site. Not sure if this means anything
at all or not...

"Timo Autiokari" wrote in message

Hi,

I've uploaded a set of unbearably accurate CRT gamma calibration charts: http://www.aim-dtp.net/aim/evaluation/gammaspace/index.htm Please have a look at them, I hope to hear if there is something to improve still.

The above is in form of CRT gamma evaluation but you can right-click the chart (of the system gamma-space that you are calibrating to) and make the chart as the background image of your desktop, there it will help AdobeGamma calibration enormously.

These chart are unbearably accurate since, with most consumer grade monitor, they make the small drift in the operation point of the monitor detectable. This drift can be rather rapid so that a change is detected within a hour or two or it can be very slow so that a change is detected only after some 8 to 24 hours of power on time.

Timo Autiokari http://www.aim-dtp.net

"Katie Piecrust" <NoSpam!> wrote:

Not sure how these are supposed to help with Adobe Gamma exactly.

*Very* much. The gamma charts cover the full tonal range and they show the error in tonal difference and in hue difference where as the gamma patches in AdobeGamma have only one level.

E.g. even if the blackpoint setup of your monitor has error you will still very easily end up with an incorrect match using AdobeGamma but the charts will show that there is error.

it's curious that I have to enter a target gamma of 2.1 when making a profile in Adobe Gamma in order to achieve 2.2 according to the charts on Timo's site.

Then your system gamma is 2.1.

To get 2.2 use the 2.2 chart, adjust the blackpoint of the monitor accurately, set the "Desired gamma" in AdobeGamma to 2.2 and then use the sliders to calibrate.

Timo Autiokari http://www.aim-dtp.net

"Katie Piecrust" <NoSpam!> wrote:

when in Adobe Gamma I have to type in the desired gamma (2.1) in order for the 2.2 chart on your website to be neutral (not c/m/y or r/g/b looking). So your saying even though the 2.2 chart on your site is the only one that is neutral after my adjustments, my gamma is actually 2.1?

Hello Katie,

Aha. What I say is: When a particular gamma chart appears as gray all over (and the blackpoint checks are apper ok too) then your system (monitor) is effectively in that gamma space (no matter what value is in the Desired Gamma input box in AdobeGamma.

What you have done is that you have some (not necessarily correct) gamma adjustments effective through the AdobeGamma sliders. Then you try to match a gamma chart using the Desired Gamma input box. This is not how the charts should be used.

Do it this way:

1. Make the 2.2 chart as the wallpaper of your desktop.
2. Adjust the blackpoint correctly.
3. Open AdobeGamma and set it to 2.2.
4. Adjust the AdobeGamma sliders so that the chart appears gray all over.

Then you are accurately in gamma 2.2. space. (it is much better to have the system in gamma 2.5 space since that is what the 99.999999% of the browsers on the Web are).

Timo Autiokari http://www.aim-dtp.net

Ok, thanks for the information and your time. I think I've got it right now based on your instructions. Just one more question regarding Adobe Gamma. I couldn't get my monitor into a 2.2 gamma space when adjusting R, G, and B gammas individually, but I could do it if I viewed them as a single gamma. Is this ok, or is it better to adjust R G and B individually? Again, many thanks!

"Timo Autiokari" wrote in message

"Katie Piecrust" <NoSpam!> wrote:

when in Adobe Gamma I have to type in the desired gamma (2.1) in order for the 2.2 chart on your website to be neutral (not c/m/y or r/g/b looking). So your saying even though the 2.2 chart on your site is the only one that is neutral after my adjustments, my gamma is actually 2.1?

Hello Katie,

Aha. What I say is: When a particular gamma chart appears as gray all over (and the blackpoint checks are apper ok too) then your system (monitor) is effectively in that gamma space (no matter what value is in the Desired Gamma input box in AdobeGamma.

What you have done is that you have some (not necessarily correct) gamma adjustments effective through the AdobeGamma sliders. Then you try to match a gamma chart using the Desired Gamma input box. This is not how the charts should be used.

Do it this way:

1. Make the 2.2 chart as the wallpaper of your desktop.
2. Adjust the blackpoint correctly.
3. Open AdobeGamma and set it to 2.2.
4. Adjust the AdobeGamma sliders so that the chart appears gray all over.

Then you are accurately in gamma 2.2. space. (it is much better to have the system in gamma 2.5 space since that is what the 99.999999% of the browsers on the Web are).

Timo Autiokari http://www.aim-dtp.net

Hi Katie,

"Katie Piecrust" <NoSpam!> wrote:

I couldn't get my monitor into a 2.2 gamma space when adjusting R, G, and B gammas individually, but I could do it if I viewed them as a single gamma. Is this ok

It is best when it can be done using the gray gamma slider only.

Some (many) monitor have differences in the r, g, b gun characteristics so then one needs to use the individual sliders.

All adjustment settings that the gray slider provides can be achieved with the r,g,b sliders also but it is somewhat more work that way.

Actually the sliders really should be arranged better in AdobeGamma, one slider should be Luminosity and two should affect to the color/hue.

BR,
Timo Autiokari http://www.aim-dtp.net

Thanks for the warning, I think. Anything in particular you can point out for me that should be avoided in your opinion?

"Chris Cox" wrote in message

Warning - Timo is a well known troll on usenet who seems to enjoy destroying other users' images. No, we don't know why he does this.

Anything you "learned" on his site is probably wrong.

Chris

"Katie Piecrust" <NoSpam!> wrote:

Thanks for the warning, I think. Anything in particular you can point out for me that should be avoided in your opinion?

Hello Katie, Mr. Cox is not well, you can find
what he points out here: http://tinyurl.com/hygv

Timo Autiokari http://www.aim-dtp.net

John wrote:

On Tue, 22 Jul 2003 21:56:25 -0600, "Katie Piecrust" <NoSpam!> wrote:
Chris and Timo do not seem to like one and other very much to say the least so most of what they say about each other is written from this starting point of view.

Chris works for Adobe and Timo does not.

However that is not to say Chris is correct, neither he or Adobe are all knowing.

I am sure that you are grown up enough to take any adivce with a great big pinch of salt and do the only sensible thing which to to try both ways for your self. Who evers method wworks best for your set up is the corrct one for you.

Good point. I would add that one side of this frog-and-mouse battle relies on personal attacks, to the exclusion of technical discussion. The other does not.

I'll leave it to you to figure out which is which.

--

Mike Russell
http://www.curvemeister.com
http://www.zocalo.net/~mgr
http://geigy.2y.net

But anyone can name themselves Chris Cox and post in a newsgroup. I don't see anything in his message headers that would point to an affiliation with Adobe either, so it makes it kind of hard to believe that this is the "real" Chris Cox. Hopefully I'm not being insulting if he is the real deal (in which case I sincerely apologize). I guess this is just another one of those take it "with a great big pinch of salt " areas that you mentioned. :-)

PS: Exactly >why< don't they like each other anyways? Chris says that following Timo's advice will lead to bad pictures, but I don't think I've seen any proof or technical discussion to back any of that up so far. And Timo's gamma evaluation charts seem to work fine from my viewpoint. Whether this is the real Chris Cox were dealing with or not, the name simply doesn't have enough authority (at least for me). Real evidence presented somewhere would be much better, and I'd be more than happy to read anything you fellows can point me to... if it exists. Thanks!

"John" wrote in message

Chris works for Adobe and Timo does not.

"Katie Piecrust" <NoSpam!> wrote in message

But anyone can name themselves Chris Cox and post in a newsgroup. I don't see anything in his message headers that would point to an affiliation with Adobe either, so it makes it kind of hard to believe that this is the "real" Chris Cox. Hopefully I'm not being insulting if he is the real deal (in which case I sincerely apologize). I guess this is just another one of those take it "with a great big pinch of salt " areas that you mentioned. :-)

Yes it is "the real" Chris Cox. Search Google's archives, this debate has been going on for years and years.

PS: Exactly >why< don't they like each other anyways? Chris says that following Timo's advice will lead to bad pictures, but I don't think I've seen any proof or technical discussion to back any of that up so far. And Timo's gamma evaluation charts seem to work fine from my viewpoint. Whether this is the real Chris Cox were dealing with or not, the name simply doesn't have enough authority (at least for me). Real evidence presented somewhere would be much better, and I'd be more than happy to read anything you fellows can point me to... if it exists. Thanks!

http://chriscox.org

RickW

"Katie Piecrust" <NoSpam!> wrote in message

The thing is that I have looked in Google's archives. All I can find is

the

continual (and rather aggressive at times) harassment of Timo, with no

real

evidence to support Chris's counter claim, or even a link to site where

the

correct information can be obtained. It seems there was a short period

where

Chris had his own pages up, but they're all 404 now. And the link you provided doesn't really prove anything in my eyes, it's just a hastily put up site with no authentic credibility that I can see. All things

considered,

it's really very hard for me to believe that this actually is the real

Chris

Cox we're dealing with, and that whom ever is behind the alias can be trusted any more than Timo. You would think if Timo's incorrectness was as serious as Chris worked so hard to make people believe over the years,

that

Adobe would have an official page up regarding it. Especially since

support

calls could be pointed to such a document so easily, saving both time and money, as well as lending a huge amount of credibility to Chris's claims that could not be denied.

Katie:

There is a lot of history here. Chris and Timo's discussions go way, way back, and yes, it was [is] the Chris Cox of the Adobe Photoshop team [see the program opening credits]. Additionally, many of Timo's "theories" have been disputed by other acknowledged experts, such as Blatner, Fraser, Knoll, et. al. Having said that, however, some of Timo's stuff is OK, and even helpful. Furthermore, Chris does not do himself any favors with the vitriolic nature of his attacks.

Nonetheless, if you do a search of their earlier communiqu

"Katie Piecrust" <NoSpam!> wrote in message

...
PS: Exactly >why< don't they like each other anyways?

Chris Cox is notorious for vehement attacks against people who criticize Photoshop. Try a Google search for Chris Cox and Dan Margulis and you'll find more of the same.

Warren Sarle wrote:

"Katie Piecrust" <NoSpam!> wrote in message

...
PS: Exactly >why< don't they like each other anyways?

Chris Cox is notorious for vehement attacks against people who criticize Photoshop. Try a Google search for Chris Cox and Dan Margulis and you'll find more of the same.

Defending your own company or view point is one thing. Attacking others is another. Here's one Cox story, and will be posted every time Cox attacks someone:
http://www.ledet.com/margulis/How_CM_Failed.pdf

=============================
Is Color Management Rocket Science?

In January, I was e-mailed some tough technical questions from a gentleman who was having trouble making the upgrade to PS 5. I wondered why he had not asked them of Adobe. It turned out that he had. Chris Cox, an Adobe programmer, had responded on-line as follows: “Start by going to the Adobe web site and reading the PS 5 technical guides (oh, and get the 5.0.2 update).” The correspondent replied, “I’ve read them several times and still have the
many questions described (and have 5.0.2).” To that, Mr. Cox’s answer was, “Well, since they clearly answer the ques-tions you posed, I have to wonder what’s wrong.”

The answers are not there. And the man Mr. Cox had blown off not only was a Photoshop instructor with a graduate degree in mathematics but, get this, a rocket scientist, claiming to have played an important design role in the launch interface for the Apollo program. The rocket scientist, having stated these credentials, shot back, “I don’t know what your problem is. Your first response to my questions showed you didn’t read my message, which clearly indicates that I had read the documents you cited. Your second reply, in addition to being totally insulting, reinforces that you didn’t read the original message as there are many, many questions not addressed by Adobe. Moreover anyone who claims that the Adobe documents answer my questions clearly is either an expert who doesn’t understand the difficulties others have or someone who doesn’t understand the difficulties of the subject…These are not straightforward issues...So, Chris, be careful with your snivelling, ignorant remarks.”

At that point, the two wisely took their conversation off-line, but not before other readers chimed in. One wrote. “I agree with [the rocket scientist]. As a Photoshop heavy user since version 1.0, I have been struggling and struggling with ICC color profiles for a while now and I just don’t get it! I’VE BEEN TO ADOBE ONLINE....I’m really pissed at Adobe. I have ruined—by embedding profiles—a bunch of scans that I don’t know how I’m going to fix…I’m sure the Adobe engineers had their heads in the right place, but I’ll be dipped in [doo-doo] if I can get my scanners, computers and printers to all work together. Sure I can go back to 4.0, but c’mon—I don’t think that’s the intent of Adobe—to send people reeling back-wards. Most people will not spend the 8-16 hours trying to write color profiles and run tons of expensive coated papers to master this crap. Let’s try to work together to share experiences and not just patly respond with trite comments.”

You don’t need to be a rocket scientist to agree with that. —DM

"Timo Autiokari" wrote in message

(Bill Hilton) wrote:

I think it all started with Timo promoting
a linear gamma of 1.0,

That, and exposing some serious bugs and other issues in Photoshop.

which, if true, would indicate that Adobe, Apple, Microsoft, pretty much every Photoshop author from Margulis to Fraser, and pretty much every color theoretician since 1935 are wrong.

snip<

Oh boy...

Stephan

In article , Katie Piecrust wrote:

But anyone can name themselves Chris Cox and post in a newsgroup. I don't see anything in his message headers that would point to an affiliation with Adobe either,

http://chriscox.org/Resume.html
(boy, I need to get that updated)

so it makes it kind of hard to believe that this is the "real" Chris Cox. Hopefully I'm not being insulting if he is the real deal (in which case I sincerely apologize). I guess this is just another one of those take it "with a great big pinch of salt " areas that you mentioned. :-)

Of course.

PS: Exactly >why< don't they like each other anyways? Chris says that following Timo's advice will lead to bad pictures, but I don't think I've seen any proof or technical discussion to back any of that up so far.

Timo is either the densest person on earth, able to ignore the advice, experience, and direct evidence given by every vision, graphics, photography expert available. Or he is deliberately trying to destroy your images. We're still not sure which, but most think he's doing this deliberately (because NOBODY could be that dense).

Almost everything he's written on how human vision works is wrong. Everything he's written about gamma and why it is used is wrong. Almost everything he's written about image processing is wrong. Everything he's written about how Photoshop works is wrong.

And
Timo's gamma evaluation charts seem to work fine from my viewpoint.

Some of them do.
But then he gives his advice on how to calibrate using them, and some of that is just plain dangerous.

(anything to do with gamma 1.0 is highly suspect)

For people not already familiar with the topic, it's dangerous.

Whether
this is the real Chris Cox were dealing with or not, the name simply doesn't have enough authority (at least for me). Real evidence presented somewhere would be much better, and I'd be more than happy to read anything you fellows can point me to... if it exists. Thanks!

We stopped posting the evidence years ago when it became obvious that Timo wasn't listening. There were many experts from different fields trying to explaim Timo's mistakes. We also posted many references and experiments he could do to disprove his claims. But he didn't listen.

I wrote http://chriscox.org/gamma/ to correct Timo's basic mistakes, and provide better references. (I need to find time to update this as well) But I don't have time to keep up with all of Timo's web pages and all the crap he spews.

Chris

In article <Yz4Ua.343457$>, Warren
Sarle wrote:

"Katie Piecrust" <NoSpam!> wrote in message

...
PS: Exactly >why< don't they like each other anyways?

Chris Cox is notorious for vehement attacks against people who criticize Photoshop. Try a Google search for Chris Cox and Dan Margulis and you'll find more of the same.

Get real.

Please stop posting Mr. Margulis's work of fiction.
It's not doing anybody any good.

Chris

In article wrote:

Warren Sarle wrote:

"Katie Piecrust" <NoSpam!> wrote in message

...
PS: Exactly >why< don't they like each other anyways?

Chris Cox is notorious for vehement attacks against people who criticize Photoshop. Try a Google search for Chris Cox and Dan Margulis and you'll find more of the same.

Defending your own company or view point is one thing. Attacking others is another. Here's one Cox story, and will be posted every time Cox attacks someone:
http://www.ledet.com/margulis/How_CM_Failed.pdf

In article , Timo Autiokari
wrote:

(Bill Hilton) wrote:

I think it all started with Timo promoting
a linear gamma of 1.0,

which, if true, would indicate that Adobe, Apple, Microsoft, pretty much every Photoshop author from Margulis to Fraser, and pretty much every color theoretician since 1935 are wrong.

All high quality digital imaging has always been and still is done in linear. Every ICC color conversion goes through linear space (even the Lab profile connection look-up space is built from linear data). All the color technology/science is based strictly on linear space.

Sigh.
Only a small part of imaging is done in a linear space, and only as necessary (which isn't nearly as often as Timo claims).

Linear encoding is useful for some scientific purposes and direct CCD readouts -- but when dealing with human vision and image processing, gamma encodings win out for quality.

It is just that the imaging industry in whole need that there is a very simple workflow so that learning curve newcomers is easy enough. That is why we have the sadRGB and that is why adobeRGB also has gamma 2.2 TRC. No more messages like "images too dark on PC" or "images too bright on Mac" etc. Sure the gamma 2.2 is a good compromise, but that compromise is good only for the industry, not for image quality.

Back to the conspiracy theory, eh?
Please read those color science books we keep pointing you to. Gamma encoding is used to make the best use of the available bits for human viewing of the images. It also has the useful property of being perceptually uniform near a gamma value of 2.5 or so -- which helps a lot of image processing techniques (and some really require that the encoding be perceptually uniform).

http://www.poynton.com/notes/Timo/Concerning_Timo.html

Please read about Mr. Poynton's "FAQs"
you'll find that his writings are enormously incorrect.

No, they are correct.
And Mr. Poynton's FAQs are peer reviewed, plus Mr. Poynton corrects his mistakes.
Timo's "faqs" have been peer reviewed and found to be incorrect, but Timo has never corrected his mistakes.

... and here, for a discussion joined in by such
authorities as Andrew Rodney and Dan Margulis ...

http://www.ledet.com/margulis/ACT_postings/ColorCorrection/A CT-linear-gamma.

htm

That indeed was an interesting thread, first Terry Britton explains the results of experimenting in the linear space e.g. like "it really does improve the quality of USM quite dramatically".... and then the industry march it.

USM is designed to work in perceptually uniform encodings. It doesn't work well at all in gamma 1.0. And you know that your examples have been debunked over and over....

Chris

Chris Cox wrote:

In article , Katie Piecrust wrote:

But anyone can name themselves Chris Cox and post in a newsgroup. I don't see anything in his message headers that would point to an affiliation with Adobe either,

http://chriscox.org/Resume.html
(boy, I need to get that updated)

"Familiar with Assembly"

..MODEL SMALL
..STACK 200H
..DATA

Name DB "C.Cox$"
Error DB "Uh oh!!$"
Msg DB "Get a real application, like Photoshop!$"

..CODE

START:

MOV AX, @DATA ; Point AX to the data segment MOV DS, AX ; AX --> DX
MOV DX, OFFSET Name ; Put offset of the file to open in DX MOV AH, 3DH ; Open file
MOV AL, 00H ; Read only
CMP PS, 14H ; See if it's Photoshop
INT 21H

JNE Problem ; Not Photoshop????!!!!!

; Here you would get the handle from AX, and do some stuff

JMP Done ; Nope

Problem:

MOV DX, OFFSET Error ; Uh oh
MOV AH, 09H
MOV BX, Msg
INT 21H

Done:

MOV AX, 4C00H ; Jump back to DOS - closing any open INT 21H ; C.Cox files.
; to close files yet.
END START

:-)

Uni

so it makes it kind of hard to believe that this is the "real" Chris Cox. Hopefully I'm not being insulting if he is the real deal (in which case I sincerely apologize). I guess this is just another one of those take it "with a great big pinch of salt " areas that you mentioned. :-)

Of course.

PS: Exactly >why< don't they like each other anyways? Chris says that following Timo's advice will lead to bad pictures, but I don't think I've seen any proof or technical discussion to back any of that up so far.

Timo is either the densest person on earth, able to ignore the advice, experience, and direct evidence given by every vision, graphics, photography expert available. Or he is deliberately trying to destroy your images. We're still not sure which, but most think he's doing this deliberately (because NOBODY could be that dense).

Almost everything he's written on how human vision works is wrong. Everything he's written about gamma and why it is used is wrong. Almost everything he's written about image processing is wrong. Everything he's written about how Photoshop works is wrong.

And
Timo's gamma evaluation charts seem to work fine from my viewpoint.

Some of them do.
But then he gives his advice on how to calibrate using them, and some of that is just plain dangerous.

(anything to do with gamma 1.0 is highly suspect)

For people not already familiar with the topic, it's dangerous.

Whether
this is the real Chris Cox were dealing with or not, the name simply doesn't have enough authority (at least for me). Real evidence presented somewhere would be much better, and I'd be more than happy to read anything you fellows can point me to... if it exists. Thanks!

We stopped posting the evidence years ago when it became obvious that Timo wasn't listening. There were many experts from different fields trying to explaim Timo's mistakes. We also posted many references and experiments he could do to disprove his claims. But he didn't listen.
I wrote http://chriscox.org/gamma/ to correct Timo's basic mistakes, and provide better references. (I need to find time to update this as well) But I don't have time to keep up with all of Timo's web pages and all the crap he spews.

Chris

In article <3f23d0c4$0$49109$>, Bart van der
Wolf wrote:

First, I appreciate you taking the time to clarify some points of view in this informal group.

Second, I understand every person participating here uses his/her way of expression, that helps avoiding dull exchanges ;-)

Third, could you explain the "odd" (some call it braindead, and I don't like it but understand the memory implications) implementation in the current (and previous to) Photoshop 7.x versions of Adjustment layer compositing? Example, 2 Levels adjustment layers on a Background layer, with exact inverse gamma (midpoint sliders e.g 0.8 and 1.25) settings show that each Levels adjustment is applied and the result rounded before the next layer is composited. This results in histogram discontinuities in 8-bit/channels. A better (image quality) approach would have been to do the *intermediate* compositing in 16-bit accuracy and round the *final* result to 8-bit again.

It's not odd or braindead - just the most direct implementation.

It is necessary in a great many cases (but that would go into details of a patent that I'm not allowed to discuss).

In the remaining cases, it just doesn't happen often enough to add the additional complexity to the code (and taking the testing hit that that would involve).

Also, we do have to maintain backward compatibility.....

So, let's get real. Is it fixed in PS8?

No, that isn't changed at all.

Chris

In article , Uni
wrote:

Chris Cox wrote:

In article , Katie Piecrust wrote:

But anyone can name themselves Chris Cox and post in a newsgroup. I don't see anything in his message headers that would point to an affiliation with Adobe either,

http://chriscox.org/Resume.html
(boy, I need to get that updated)

"Familiar with Assembly"

OK - so some parts of the resume are a bit understated.
I just couldn't remember all the processors I've dealt with assembly code for (and some of them are so specialized that nobody would know them anyway).

And I'd guess from that code that you've been doing a lot of 8085 work, or you've been doing x86 assembly for far too long...

.MODEL SMALL
.STACK 200H
.DATA

"Flycaster" wrote

Blatner, Fraser, Knoll, et. al.

Not so many et.al.'s however, just the few Adobe/Photoshop marionettes and employees.

I have a hunch that Adobe could officially care less
what Timo does or says about monitor calibration,

Officially Adobe does not "care" what I do or say, or if they do "case" they never say anything. The mud-slinging from Mr. Cox is not official Adobe.

provided he refrains from maligning their product.

The very only way to get bugs fixed in Photoshop in timely manner is to make them public. Some of the bugs are (have been) rather difficult to comprehend/undestand so often some demonstrations are (have been) needed. This is not maligning. Yes, all the other routes for bug fixes have been tried many many times.

From my experience, the vast majority of folks who
seriously use Photoshop are way beyond using Adobe Gamma

Actually no, AdobeGamma is being very widely used. Like it was in the past with Macs, the Knoll Gamma Applet was almost solely used. One needs a very expensive spectrophotometer and very expensive SW in order to get only slightly better results, the low cost monitor calibration gadgets are far inferior to AdobeGamma.

Timo Autiokari http://www.aim-dtp.net

In article , Timo
Autiokari wrote:

"Flycaster" wrote

Blatner, Fraser, Knoll, et. al.

Not so many et.al.'s however, just the few Adobe/Photoshop marionettes and employees.

I just love Timo's conspiracy theories....
And I love how so many researchers, companies and standards bodies are in a conspiracy with companies that weren't formed until long after the data was published....

provided he refrains from maligning their product.

The very only way to get bugs fixed in Photoshop in timely manner is to make them public.

No, just tell us about bugs and they get fixed.

Some of the bugs are (have been) rather difficult
to comprehend/undestand so often some demonstrations are (have been) needed. This is not maligning. Yes, all the other routes for bug fixes have been tried many many times.

Just because you don't understand something, doesn't make it a bug.

Chris