Gamut Hell Test Image (hands-on post processing exercise)

Discussion in 'Open Discussion' started by Promit, Nov 24, 2013.

  1. Promit

    Promit Mu-43 All-Pro

    Jun 6, 2011
    Baltimore, MD
    Promit Roy
    There's an on-going thread about color-space here:
    https://www.mu-43.com/showthread.php?t=43276
    The point of discussion is one that comes up many times -- what's the deal with sRGB, AdobeRGB, and print gamuts? Which one is preferable?

    To help illustrate some of the difficulties in dealing with expanded gamuts, I'm sharing a full RAW file (24 MP Sony A65) to test with:
    https://dl.dropboxusercontent.com/u/12879227/Photos/DSC01761.ARW
    This particular image is special: it's a real world image that is almost entirely outside of sRGB gamut in the blue channel. Bumping up the global saturation will exasperate the situation even further. Please download it and take a look at what you get straight out of your preferred converter, before and after tweaking. This will be most informative for people who have a wide gamut monitor next to a standard sRGB monitor, and ideally are willing to make a few print proofs too. In LR, I have to pull the saturation down to about -40 and the blue channel a bit farther still before I can produce an image that reproduces reasonably well on sRGB devices and print media.

    For those of you who are suitably equipped, you'll notice that the basic image reproduces significantly different color tones between wide gamut and sRGB screens, as well as being very sensitive to calibration, color temperature, and print settings. Also try seeing what happens to Adobe RGB JPEGs on color managed and non-color managed apps, and how rendering intent affects the output -- if at all. I don't know how many of you have seen such extreme color images before, so I'm curious to hear how your experience is in post-processing this one. Please share your thoughts, as well as any conversions you care to post. I've been meaning to put this file out there for a while after encountering it, and I'm wondering if others find it as much of an oddity as I did.

    If others have wide-gamut images to share, that would be great too.