Sunday, August 10, 2014

Further quantification of the Mavericks color management problem

EDIT: Adobe fixed this bug for most types of display profiles in LR 5.7

I spent some time further quantifying the display problem that Mavericks introduced and that affects Lightroom, Aperture, and every other application that uses Apple color management libraries. (EDIT 10/19/14 - Apple fixed this bug in Aperture, right now it only affects Lightroom and Safari - all other color managed apps are fine - in Yosemite the problem persists). In short, the problem is that shadows get crushed upon display. This is a serious bug that is remaining unfixed since OS X 10.9 and is apparently present even in the Yosemite beta. I am trying to raise awareness of this bug since I am getting no reply from Apple not from a bug report and not from directly emailing folks there. This should get fixed as it makes it tough to do serious work on Mavericks. You can work around it by using Photoshop which uses its own color management library or by using the soft proof feature in Lightroom. Mac OS X 10.8 and below do not have this problem and correctly show the shadows. This is independent of what color calibration you use and even shows up when you use Apple's supplied profile for your display.

I generated a simple photoshop file that has swatches of grey ranging from 1 to 100 in 8-bit scale and then used the system color taste dropper that you can get to if you open textedit and click the text color box. Then use "Show colors" and you can then "taste" any color on your screen and get the display values. These values are what is actually sent to the monitor and so are very useful for this purpose. Below I plot the values seen in Photoshop (correct), those in Lightroom Library and Lightroom Develop. I am not showing Aperture as those are the same as Lightroom Develop and also very wrong. I am using a double log scale to really show you the problem areas in the darker regions below r,g,b=25.

I did this using the nice plotly plotting service. The images sometimes take a short time to show up. You can find the data in the link on the bottom of the plot. Photoshop's light bump in the shadows is correct as sRGB has a little knee in the shadows. Lightroom Develop due to the Mavericks bug displays way lower intensity than it should leading to the crushed shadows that people are observing.

I also created the same swatch file in the color space of my monitor profile. The display of those swatches should happen at exactly the same display value as the input file. This really illustrates the problem I think.

Photoshop clearly does this correctly. The relation is almost exactly linear and any deviations are a single bit difference which is just a rounding error. Lightroom Develop shows way below. Lightroom Library is close but with a larger error than Photoshop. Below is the same data bit plotted as display error.

Mavericks causes Lightroom Library to be off by a full 8 points in the shadows! I hope this data is useful to somebody and helps some folks that have puzzled over dark shadows in Mavericks applications.

13 comments:

  1. What puzzles me Jao is why isn't someone at Adobe and Apple looking at correcting this. Have you contacted either Apple or Adobe about this and if so, I'm curious about the outcome. I'd be happy to talk to both support organizations if it would help at arriving at a desirable outcome.

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  2. I've contacted both but haven't gotten any traction out of either. Not even an acknowledgment.

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  3. Hey Jao, just bought a 2014 15" Retina and got the same issue ... The blacks are crushed, I can't work with that and that's a pity 'cause I love that machine ... Any solutions?

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    1. Haafling, the solution I have found is to turn on soft proofing in the Develop module and soft proof to your display profile. This will apparently force Lightroom to use the Adobe color management chain instead of Apple's. It will slow down Develop but at least your blacks won't be crushed to death.

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  4. Thank you for you fast reply! I'll try that. Is there any solutions for others activities like watching movies? I tried with a blu-ray and the dark scenes of the movie were unwatchable, absolutely no details in the dark area ...

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    1. How are you watching BluRays on Mac OS X? That is not natively possible. I would suspect the player application in that case as such apps do not go through the color management system at all and just send straight to the video driver. If you get blocked shadows in that case, I would suspect that either the app is buggy or set up incorrectly, or that your display calibration is not correct. I would first recalibrate the screen.

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  5. Hi Jao,

    I can confirm the problems you are experiencing on my 2011 MBP on both the built-in display and my Eizo CG246. I get very similar results to your plots above, using the DigitalColor Meter.app (/Applications/Utilities/DigitalColor\ Meter.app) in the native RGB color values for my displays. I get the feeling the problem goes largely unnoticed because of the lack of large areas of deep shadow detail in most images, even on calibrated and profiled displays for educated image processors and photographers. However, when you attempt to export/save an image into sRGB that has a large area of deep shadow detail and then view it in these crippled applications, the effect is obvious.

    I appreciate your writing about this issue because I thought I was going crazy with my color managed workflow, ever since I upgraded to Mavericks. I have managed to anticipate the issues and I work mostly in PS, so at least I can stay somewhat isolated from the issue, but it is puzzling that Apple has been silent on this issue. The system-wide color management seems arbitrarily broken, which makes tracking down these issues methodically even more difficult.

    I appreciate your effort.

    Thanks,

    kirk

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    1. Kirk. I can actually give you some good news that Adobe has found the cause of the problem and is fixing it for Lightroom. You can see some discussion on this here: http://feedback.photoshop.com/photoshop_family/topics/lightroom_5_icc_profiles_clipped_shadows_under_osx . Apple did fix this for Aperture with Yosemite, but Safari is still wrong. I have a bug report in their bug system to this effect and they have looked at it. For now I am happy that Adobe will at least fix Lightroom.

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    2. Thank you! I am not a frequent Lightroom user, but I tested the Library/Develop module problem with a patch image like yours - the image was 1) rendered in sRGB and tagged sRGB and 2) CONVERTED to AdobeRGB and tagged with AdobeRGB. I imported both images into Lightroom (5.4) in Mavericks (10.9.5). They both appeared identical and correct in the Library module - HOWEVER, they both appeared identical and INCORRECT (crushed shadows) in the Develop module. There is a brief period where the preview of the full image is rendered "correctly" and then the Lightroom rendering crushes the blacks, regardless of whether or not the image is sRGB or aRGB.

      This is different but probably related to the problems in Safari, where sRGB images have the blacks crushed but AdobeRGB images are displayed properly.

      Totally messed up.

      I have been following the thread on the Lightroom forum through the think on your blog.

      kirk

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  6. Just to let you know, I brought this to the attention of Lloyd Chambers (Diglloyd) and, after a couple of email exchanges, he confirmed what you are experiencing as well. He wrote up a brief description of the issue and the link to your blog:

    http://diglloyd.com/blog/2014/20141103_1208-OSX_Yosemite-clipped-blacks.html

    kirk

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    1. Kirk, thanks for publicizing this quite annoying issue. Maybe this will precipitate some fixes if more people become aware.

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  7. This comment has been removed by the author.

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  8. This big in Lightroom has been fixed with LR 5.7. See here

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