Pages: 1 2 3 [4] 5 6 7   Go Down

Author Topic: OSX Colour Management Problems  (Read 99787 times)

sarangiman

  • Newbie
  • *
  • Offline Offline
  • Posts: 30
OSX Colour Management Problems
« Reply #60 on: March 01, 2007, 02:09:45 am »

With all due respect, Serge, I wasn't born yesterday. I just happen to post on different sites (try photo.net or Adobe's forums). I was only led over here via an Adobe forum.

But good of you to ask 'why all of a sudden?' I believe that this is generally due to a lack of knowledge & understanding... which is why we come to these forums to *learn* from one another. I could sit here and say: 'Half the 'observations' in this thread have hardly been more than just ignorant... "sRGB images should look the same in color-managed & non-color-managed applications"... give me a break'. For example. But that would be rude, given that I might have been saying that a 5 months ago before I read up on the theory of color management.

Anyway, all unpleasantries aside...

I just calibrated my Sony Trinitron CRT, and I get consistent color across my CRT and my MacBook Pro LCD, leading me to believe that this 'yellow' cast is just due to the fact that I've been dealing with oversaturated oranges on my MacBook Pro all along.

Additionally, it's now very apparent why my MacBook Pro monitor profile oversaturates yellows... the native response of this LCD seems to be quite lacking in yellows. After calibrating both my LCD and CRT, a 16 bit 20MP film scan of a sunset ends up mostly orange on my MacBook Pro LCD, but with subtle yellow hues showing up on my Sony CRT. Some of these yellows show up on my MacBook Pro LCD, but *only* after hardware calibration. Before that, it was completely skewed orange ('canned' Apple profile). Apparently, this LCD just stinks at reproducing yellows; the calibrated profile attempts to regenerate these yellows by oversaturating yellows...

I may be wrong; feel free to chime in.

-Rishi Sanyal
« Last Edit: March 01, 2007, 02:11:56 am by sarangiman »
Logged

Tim Lookingbill

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 2436
OSX Colour Management Problems
« Reply #61 on: March 01, 2007, 02:32:20 am »

saranqiman,

The changing of the CM preview from yellow to normal viewed on the Sony after clicking over to the Sony screen is a normal behavior on dual display Mac systems. This was confirmed to me a while back by Andrew Rodney in Adobe forums. He also confirmed that clicking back to the main display retains the correct CM preview which shows that the video system is using both profiles correctly associated to their respective display. It just takes clicking to the other display to update it.

I'm wondering if some type of update by clicking is involved with calibrators because I don't know how the software is suppose to know which associated profile/vLUT it needs to clear before measuring the response of one display while the other is attached to the same video card. Is there a section in the software that allows choosing?

Also, when you say a color/document is "IN" a particular color space it helps to know whether you converted to or assigned the profile. When it comes to purities there usually isn't that much of a change except maybe in luminance when you assign different working space profiles.

What does 255 combo RGBCMY color patches look like on the MacBook compared to the CRT when viewed in a nonCM app with both displays made to look identical in only luminance and color cast? Then load the calibration software for the MacBook and click forward to the section where the vLUTs clear. The screen may at first become brighter depending on the brightness level set during the previous calibraton and then darken. That's the true response of the display without a profile loaded from which the calibrator measures. If the color patches still look the same then the MacBook's native gamut is close to sRGB. If they look different in hue and intensity, then you're dealing with a display whose gamut is limited and which the calibrator can not improve upon thus causing hue shifts like purplish blues in CM previews.

Another concern I have that didn't get addressed in this thread is Andrew's calibrating the MacBook to a luminance of 85cd/m2. That's too dark for the majority of LCD's calibrated. It's recommended to calibrate between 100-120cd/m2. This darker calibration may reduce the gamut of the MacBook causing problems with the calibrator in how it writes the profile.
Logged

Serge Cashman

  • Full Member
  • ***
  • Offline Offline
  • Posts: 200
OSX Colour Management Problems
« Reply #62 on: March 01, 2007, 02:34:11 am »

My apologies, Rishi.

Here's my theory so far - the native state of the LCD is on the blue side. Then the calibration software tries to correct it with the videocard LUTs, but because of the crude nature of the correction (this being a laptop) it still measures the monitor as lacking in oranges. So the colormanaged software in turn tries to compensate for that.
Logged

sarangiman

  • Newbie
  • *
  • Offline Offline
  • Posts: 30
OSX Colour Management Problems
« Reply #63 on: March 01, 2007, 03:28:56 am »

The changing of the CM preview from yellow to normal viewed on the Sony after clicking over to the Sony screen is a normal behavior on dual display Mac systems. This was confirmed to me a while back by Andrew Rodney in Adobe forums. He also confirmed that clicking back to the main display retains the correct CM preview which shows that the video system is using both profiles correctly associated to their respective display. It just takes clicking to the other display to update it.

In Lightroom, all you need to do is drag greater than 75% of the application over to the other monitor, and then you see the application correct colors for the new monitor. I.E., when I drag from my MacBook LCD to my Sony Trinitron, initially (for a fraction of a second) the a sunset image looks intensely yellow... a fraction of a second later, when Lightroom recognizes and uses the Sony Trinitron monitor profile, oranges are re-established and yellows subdued (again, here is where the compensation via oversaturation of yellows for the MacBook LCD is apparent).

I'm wondering if some type of update by clicking is involved with calibrators because I don't know how the software is suppose to know which associated profile/vLUT it needs to clear before measuring the response of one display while the other is attached to the same video card. Is there a section in the software that allows choosing?


This is a very good question. I wondered it myself. All I did was drag the application over to the Sony Trinitron. But, tomorrow, I will try a 'better' method. That is, I will put the MacBook Pro to 'sleep', then connect the Sony Trinitron along with a keyboard/mouse. This wakes up the MacBook Pro *without* turning on the built-in LCD, and uses the external monitor ONLY. Let's see if profiling using Eye-One this way produces a different profile. I will post again with my results.

Also, when you say a color/document is "IN" a particular color space it helps to know whether you converted to or assigned the profile.


I always meant 'converted to', except where I created a new 200x200 pixel image 'in' a particular color space (i.e. PS allows you to select the color space of a newly created image).

When it comes to purities there usually isn't that much of a change except maybe in luminance when you assign different working space profiles.


Yes, which is why when I 'convert to' between sRGB and Adobe RGB and Apple RGB (all permutations & combinations), I don't get much change (i.e. maybe it'll go from 0,0,255 to 0,0,250). However, anytime I 'convert to' a wide-gamut color space, raw RGB values change quite a bit. I believe this has something to do with the fact that wide-gamut spaces, such as ProPhoto RGB, actually encompass 'imaginary' colors. Perhaps 0,0,255 in ProPhoto RGB is 'imaginary', so 0,0,255 in sRGB gets mapped to 94,0,255 in ProPhoto RGB... and 94,0,255 is the pure primary blue.


Another concern I have that didn't get addressed in this thread is Andrew's calibrating the MacBook to a luminance of 85cd/m2. That's too dark for the majority of LCD's calibrated. It's recommended to calibrate between 100-120cd/m2. This darker calibration may reduce the gamut of the MacBook causing problems with the calibrator in how it writes the profile.

I used a luminance of 120 cd/m2.

[a href=\"index.php?act=findpost&pid=103947\"][{POST_SNAPBACK}][/a]
Logged

sarangiman

  • Newbie
  • *
  • Offline Offline
  • Posts: 30
OSX Colour Management Problems
« Reply #64 on: March 01, 2007, 04:15:01 am »

OK, I was able to get rid of a good portion of this yellow cast by recalibrating my display -- this time, making sure that all lights were off in my room, OS X dock hidden (itself provides some light which I guess might leak into the colorimeter), etc. Also, this time I used 90 cd/m2 for my luminance, since it was 'recommended' for laptop LCD screens (don't know why?).

Now images *really* look similar between my CRT and my MacBook Pro LCD. Images exported for web (sRGB) and then viewed in non-color-managed programs look *similar*, but a little more saturated and missing details in the shadows.

Tomorrow morning I'll post some 3-D plots showing a comparison of the canned Apple profile for the MacBook Pro LCD vs the profile my Eye-One colorimeter made (in comparison to sRGB color space). I think it will make it apparent why the canned Apple profile oversaturated oranges and not yellows, among other things.

Also, the plot of the calibrated profile of my MacBook Pro shows quite an extension into the blues... which would corroborate Serge's comment... is that right (I don't claim to understand the intricacies of 3-D plots of color profiles, so any help would be appreciated here)?

-Rishi
« Last Edit: March 01, 2007, 04:17:25 am by sarangiman »
Logged

Andrew Fee

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 87
    • http://
OSX Colour Management Problems
« Reply #65 on: March 01, 2007, 01:12:34 pm »

I apologise for not replying sooner.

Quote
OK, a few fundamental things we need to work out:

1.) So you're satisfied now that colors look OK only when your MacBook Pro is hooked up to your CRT? Now, ditch the CRT, restart MacBook Pro. Are you still getting 'correct' colors?
I have done that, and everything has stayed the same. However, while this orange box now looks correct, I've gone through some more images and blues still look wrong.


Quote
2.) Please answer Serge's question: what monitor profile is OS X now using?
Everything is using the correct profiles. (macbook profile on the macbook display etc)

Quote
3.) To a number of the posters here: who the heck made it up in their minds that color-managed applications and non-color-managed applications are *supposed* display the same colors for a sRGB image when color management is properly set up and monitors are profiled? This is crazy, and would *only* be true if your monitor's profile, after proper hardware calibration, happened to basically be the exact inverse transform of the sRGB profile. And that would be true only if your monitor had a very 'sRGB-like response' (as Serge points out).
I was under the impression that I should have been able to get consistent colour in both Safari and Firefox when exporting to the web, as I believed that unmanaged applications were basically treated like they were tagged with sRGB however I now know that this is wrong.


Quote
Another variable is Andrew's relying on the accuracy of his Fuji F30's LCD preview matching what he's suppose to see in sRGB on his system. Those tiny 2" camera LCD previews aren't calibrated and can't be trusted for accuracy. I had the F10 and it never showed hue/saturation the same way as it did in sRGB on my calibrated system nor did it match the scene as shot. Its LCD previews were always a bit oversaturated with very cyanish greens and overly reddish browns.
I wasn't saying that the screen was accurate (I know that it isn't) just that the colour on that screen matched up very closely to what I actually saw with my eyes when taking the photo, and what I was seeing in unmanaged applications.

Quote
Andrew, if you get the chance view the linked image at the bottom and assign sRGB, your CRT or Toshiba profile in what ever color managed app that allows it. The image is a composite of elements from several test targets which contain colors that shift noticeably when viewed in CM apps while changing the system display profile.

The reds should look hot red, not orange. The patch of blue to the right of the yellow PhotoDisc rectangle should look sky blue not purplish or violet. The yellows should not look overly cyanish or reddish. The womans head scarf should be slightly magenta-ish, but not orange. None of the colors should appear to glow as if oversaturated except the RGBCMY color purities.

http://luminous-landscape.com/forum/index....ype=post&id=835
[a href=\"index.php?act=findpost&pid=103927\"][{POST_SNAPBACK}][/a]
Yellows look yellow, the head scarf is slightly magenta and that blue box does look blue... though I'm not sure I would call it "sky blue."

However, in the row of colour patches (RGBMYC) the values are:

Red - 254, 0, 0
Green - 0, 255, 1
Blue - 38, 1, 255
Magenta - 255, 0, 254
Yellow - 253, 254, 0
Cyan - 1, 255, 255


I am going to do another calibration at a higher brightness to see if that helps, though the trial of ColorEyes display Pro is going to expire after this one now - it kept crashing when trying to calibrate the CRT last night, using up 6/7 of my 9 runs.

I think I will be buying the software soon though, as I am very impressed with the profiles it generates compared to the Spyder software. (which often leaves a slight green tint in the darker areas) I just need to decide whether to buy the software itself, or to get the DTP-94 bundle. (is it worth it as an upgrade from the Spyder?)
Logged

orangekay

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 65
OSX Colour Management Problems
« Reply #66 on: March 01, 2007, 05:07:13 pm »

Quote
I'm wondering if some type of update by clicking is involved with calibrators because I don't know how the software is suppose to know which associated profile/vLUT it needs to clear before measuring the response of one display while the other is attached to the same video card. Is there a section in the software that allows choosing?

On the Mac, you get/set the LUT by display ID using a function called CMSetGammaByAVID. So long as the OS recognizes a display as unique (i.e. non-mirrored), you can futz with its gamma table.
Logged

sarangiman

  • Newbie
  • *
  • Offline Offline
  • Posts: 30
OSX Colour Management Problems
« Reply #67 on: March 01, 2007, 05:37:11 pm »

Yeah, I still don't like what my Eye-One monitor profile is doing with blues.

What should be 'sky blue' in that target looks 'sky blue' *unmanaged* applications, but looks lighter and more violet in color-managed applications.

What particularly bothers me:

In a color-managed application:
-0,0,255 square made in the ProPhoto RGB space looks like irridescent pure blue
-0,0,255 square made in the sRGB space looks lighter/more violet, which is explained by the fact that when I *convert to* this image in Photoshop to my monitor profile, 0,0,255 becomes 94,0,255 (some red is thrown in there)

In a non-color-managed application:
-0,0,255 square made in the ProPhoto RGB space looks like irridescent pure blue
-0,0,255 square made in the sRGB space looks like irridescent pure blue

So, there's got to be something going on with the monitor profile... as Andrew & I are both experiencing. Must have something to do with the profiler/software.

Rishi
Logged

sarangiman

  • Newbie
  • *
  • Offline Offline
  • Posts: 30
OSX Colour Management Problems
« Reply #68 on: March 01, 2007, 05:44:49 pm »

Andrew,

I also get the same colors for the RGBMYC strip.

That is, in Photoshop, when I assign the sRGB profile, I get:

38,1,255

I'm assuming this is an error in the target file.

When I convert this image from sRGB to my monitor profile, I get:

R: 245,36,0
G: 0,255,0
B: 101,0,255
M: 255,0,255
Y: 240,255,0
C: 79,254,255

To anyone informed enough to comment: do these adjustments that my monitor profile is making seem reasonable? Is that even a valid question to ask?

At any rate, I wish it weren't doing to blue what it's doing. It just looks strange to me (and Andrew, apparently).

-Rishi
Logged

Serge Cashman

  • Full Member
  • ***
  • Offline Offline
  • Posts: 200
OSX Colour Management Problems
« Reply #69 on: March 01, 2007, 09:03:48 pm »

Quote
On the Mac, you get/set the LUT by display ID using a function called CMSetGammaByAVID.

Could you elaborate on that? How do you actually apply it?

Also, do you know which applications are aware of both profiles? My impression is that Photoshop is aware of all of them but Safari only uses one. Possibly Lightroom uses only one (I'm just trying to find an explanation why a CRT profile would fix the problem).

[edit] Also, if the guys with macbooks could just post profiles of a native state of the screen (without any LUT calibration applied) it could be possibly helpful.
« Last Edit: March 01, 2007, 09:09:44 pm by Serge Cashman »
Logged

jackbingham

  • Full Member
  • ***
  • Offline Offline
  • Posts: 205
    • http://www.integrated-color.com
OSX Colour Management Problems
« Reply #70 on: March 01, 2007, 09:30:10 pm »

To anyone informed enough to comment: do these adjustments that my monitor profile is making seem reasonable? Is that even a valid question to ask?

At any rate, I wish it weren't doing to blue what it's doing. It just looks strange to me (and Andrew, apparently).

-Rishi
[a href=\"index.php?act=findpost&pid=104079\"][{POST_SNAPBACK}][/a]
[/quote]

For starters there is no reason to convert an image to a monitor profile. A monitor profile is a piece of information describing monitor behavior. It is not something that should ever be assigned or converted to an image. Second, when you assign a profile to an image the numbers don't change, only when you convert. There's a whole lot of thrashing going on here that is scary but the most frightening thing I've seen is a statement about how a particular image on screen under certain conditions looks the most like when it was shot. I'm sorry people we just don't have that good color memory. I heartily recommend placing an object under a good viewing light to compare it with an image on screen but to compare an image on screen with what you remember can only lead to trouble in River City
Logged
Jack Bingham
Integrated Color Corp Maker

Serge Cashman

  • Full Member
  • ***
  • Offline Offline
  • Posts: 200
OSX Colour Management Problems
« Reply #71 on: March 01, 2007, 09:41:35 pm »

Jack, their problem is that a monitor calibrated to some very mainstream targets (6500K/2.2, Native/2.2) displays test sRGB images in color managed  aplications with an obvious tint compared to non-colormanaged applications. I don't think it's normal. There can be some expected differences because of different gammas and different gamuts but I don't think you should expect oranges turn red and blues turn purple.

[edit] I understand your point about the photograph, but they also use some generic test images.
« Last Edit: March 01, 2007, 09:43:17 pm by Serge Cashman »
Logged

Tim Lookingbill

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 2436
OSX Colour Management Problems
« Reply #72 on: March 01, 2007, 09:49:59 pm »

I forgot to add, don't go by the numbers in that file, just make sure you don't see purple blues and that other colors are as I described which you all have confirmed so your calibrations are right on. That shot is a screengrab because I'm too lazy to resize in PS and mess with the sharpening issues when downsizing. The numbers are generated from what Apple Digital ColorMeter reads off the adjusted vLUT of CM images. Those numbers represent my i1 Display profile which is very close to sRGB. If I convert to sRGB and Soft Proof with MonitorRGB I see the reds turn a bit orangish but it's subtle with numbers increasing in green considerably in ADM so I didn't want to introduce that and complicate things.

I started assigning Andrews CRT, Apple sRGB and Toshiba TV profiles except the 1-Color LCD and there wasn't much change. I was just wanting to establish that what you all are seeing is what I'm seeing.

I haven't been on the web all day so sorry I didn't get back to you on this sooner to prevent any unnecessary calibration. I just got my refurbed G5 iMac and my first look at an Apple LCD and I'm just beside myself. APPLE DEFINATELY KNOWS NEUTRAL. Just using the default iMac canned profile and it matches my calibrated CRT attached to my 2000 Pismo. The linked color target is spot on except the Apple's WB and gray is much more neutral looking. My CRT leans a little on the blue side both white and gray. The only problem is the iMac's barely noticeable yellowish tinge extending in about 3 inches from each side. Oh well, it's a refurb.
Logged

Tim Lookingbill

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 2436
OSX Colour Management Problems
« Reply #73 on: March 01, 2007, 10:19:27 pm »

Here's the original file in its original AdobeRGB space according to the numbers. It is tagged with AdobeRGB so you will have to convert to sRGB on your system and compare in CM and nonCM apps.

I remade the 255 RGBMYC purities in AdobeRGB so when you convert to sRGB they will change. What you need to do is make your own purities in that file and see how different they look in CM and nonCM apps before and after converting. All jpg compression induces rounding errors in 255 colors so they won't be exactly 255 in some if not all.

When I upload this image to this forum I think the profile gets stripped so you'll need to check when you drag and drop if it retains the AdobeRGB profile.
Logged

Tim Lookingbill

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 2436
OSX Colour Management Problems
« Reply #74 on: March 01, 2007, 10:56:17 pm »

I induced the purplish blues in CM previews by loading an iiyama monitor profile as my system profile. It has a slightly larger gamut. The image at the bottom shows a screengrab of the same color target converted to sRGB. Compare it to the original AdobeRGB version. Dont' go by the numbers in the purities as accurate.

Another thing to watch out for in judging these purples, yellows and oranges is to allow your eyes to adapt to the blue background of this forum which can make these colors more pronounced at first glance. Let adaptation kick in for awhile viewing in a neutral surround.

This PhotoDisc target was made specifically to induce this type of adaptive color shifting especially in the fleshtones caused by the bluish backgrounds in the portraits next to the 5500K lit foamboard in the sunflower section.

This target has the potential of driving press operators bonkers as it should.
Logged

orangekay

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 65
OSX Colour Management Problems
« Reply #75 on: March 02, 2007, 04:11:13 am »

Quote
Could you elaborate on that? How do you actually apply it?

I'm not sure what you mean. The function is documented here:

http://tinyurl.com/2rawkd

And here's a brief example of it being used to clear out the LUT:

- (void) linearizeLUT: (id) sender
{
    CMError    err      = noErr;
    CMVideoCardGamma    gamma;
    Fixed    baseGamma    = FloatToFixed(1.0);
    Fixed    minGamma    = FloatToFixed(0.0);
    Fixed    maxGamma    = FloatToFixed(1.0);
    
    gamma.tagType    = cmVideoCardGammaFormulaType;
    gamma.u.formula.redGamma    = baseGamma;
    gamma.u.formula.redMin  = minGamma;
    gamma.u.formula.redMax  = maxGamma;
    gamma.u.formula.greenGamma    = baseGamma;
    gamma.u.formula.greenMin    = minGamma;
    gamma.u.formula.greenMax    = maxGamma;
    gamma.u.formula.blueGamma    = baseGamma;
    gamma.u.formula.blueMin  = minGamma;
    gamma.u.formula.blueMax  = maxGamma;
    
    err = CMSetGammaByAVID((DisplayIDType)CGMainDisplayID(), &gamma);
    
    if ( err == noErr )
    {
  gLUTCleared = true;
    }
}

Apologies for the formatting; this forum doesn't seem to like tabs.
Logged

Serge Cashman

  • Full Member
  • ***
  • Offline Offline
  • Posts: 200
OSX Colour Management Problems
« Reply #76 on: March 03, 2007, 10:11:30 pm »

LOL. I mean - me being neither an OS X tech support guy nor a programmer - how do I make it work? Or can I make it work at all?

My goal is  to clear the LUTs. What do I do? Run the terminal and type the code you've posted?
« Last Edit: March 03, 2007, 10:15:59 pm by Serge Cashman »
Logged

orangekay

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 65
OSX Colour Management Problems
« Reply #77 on: March 04, 2007, 03:55:02 am »

Quote
LOL. I mean - me being neither an OS X tech support guy nor a programmer - how do I make it work? Or can I make it work at all?

My goal is  to clear the LUTs. What do I do? Run the terminal and type the code you've posted?
[{POST_SNAPBACK}][/a]

You can run that exact block of code by installing [a href=\"http://www.khiltd.com/Downloads/KHIProfileMenu.zip]this[/url] and choosing "Clear Video Card Gamma LUT" from the ColorSync menu it throws up in your menu bar. Otherwise, no, you can't really make it work without an engineering background.
Logged

sarangiman

  • Newbie
  • *
  • Offline Offline
  • Posts: 30
OSX Colour Management Problems
« Reply #78 on: March 04, 2007, 06:07:42 pm »

Jack,

I understand that converting to a monitor profile is rather inane; but I was not doing it in an uninformed manner.

I wanted to see what color-managed applications, using my Eye-One generated monitor profile, are doing to my blues to make them purplish.

The fact that converting to my monitor profile makes 0,0,255 go to 94,0,255 means that color-managed applications are telling my monitor to throw in some reds into blue regions... and I suspect that it is this particular behavior that might be turning blues toward purplish (given that the color purple is formed by: 128,0,128).

Also, although applying the monitor profile brings out great shadow details, I am still seeing the 'blown-out' neon-like green in the original color test pattern that Andrew posted (he also had the same complaint about neon-like greens).

Andrew, have you been able to explain these observations yet?

-Rishi
Logged

sarangiman

  • Newbie
  • *
  • Offline Offline
  • Posts: 30
OSX Colour Management Problems
« Reply #79 on: March 04, 2007, 09:59:11 pm »

Andrew,

Just a heads up:

I've solved the puzzle. As to why you and I are seeing blues turn purplish for sRGB images.

It's because our hardware profilers have profiled our monitors as having a response in the blues outside of the sRGB gamut. Check for yourself using the ColorSync Utility. I checked my profile as well as yours (1-Color LCD).

I'm writing up a lengthier post to clearly explain what is happening.

In the meantime, would anyone like to offer their opinion on this:

--Is it reasonable to believe that our MacBook Pro LCDs truly have a response in the blues outside of the sRGB gamut (even my Sony CRT does not), or did our hardware profilers just screw up?

Thanks,
Rishi
Logged
Pages: 1 2 3 [4] 5 6 7   Go Up