I don't believe this is a complicated question - when I work win lab and flip to RGB, the default space is SRGB. hence there is clipping and repositioning of the numbers. Id like to know how, when I convert from lab to RGB - I can take it into widest space with perceptual rendering.

Is this possible ?

  • 1
    It might help if we knew what software you are using.
    – Tetsujin
    Mar 20 at 12:38
  • Switching from Lab to sRGB will produce exactly the same RGB values whether perceptual or colorimetric. There is a notion that perceptual spreads/smooths out of gamut colors whereas colorimetric conversions clip. This is true for most ICC printer profiles but sRGB, Adobe RGB (1998), ProPhoto RGB, and other tricolor profiles are matrix based and use math to convert. For these perceptual and colorimetric are usually the same. A few have made LUT sRGB profiles but they are not used much and are non-standard.
    – doug
    Sep 18 at 19:57

No. It is not possible. The sRGB color gamut can’t be made wider. Making it wider makes it something else, Adobe RGB for example.

The reason to use a Lab based workflow is to reduce the effects of cumulative rounding errors and facilitate tools tuned to make adjustments based on human perception.

In typical implementation, cumulative rounding error is reduced by using floating point values rather than integers. Human perception is accounted for by the LAB model itself.

The goal of the LAB model is equations that account for human perception, so it is still numerical of course.

Using the LAB model means that you only have to deal with out of gamut colors once at the end of your pixel pipeline not each time an out of gamut value occurs. Effectively, this means out of gamut can be adjusted at the output device level, such as sRGB for displays and CYMK for print.

Keep in mind that most work is not color critical and handling out of gamut color automatically is almost always good enough. It is not good enough when you can actually see the difference and the difference is wrong and all the other reasons things can go wrong with color are known not to be the problem.

This is almost never the case in photography.


Programs such as Photoshop allow you to change to a variety of color spaces like sRGB, Colormatch RGB, Adobe RGB, and ProPhoto RGB (listed in order from smaller to widest color gamut). Does the image editor you use have this functionality? You don't mention what software you're using.

BTW, it's best to convert to sRGB when you package images for customers since their image viewers may not accommodate color spaces outside of sRGB. Viewing Prophoto color space on an image viewer that only handles sRGB looks dingy.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.