Pro9000 mkII and sRGB vs. ProPhoto

Started Nov 23, 2012 | Discussions thread
technoid Senior Member • Posts: 2,036
Comparing out of gamut impact requires looking at the region.

One of the curious aspects of looking at the "out of gamut" grey mask (ctr-shift-Y) is that one can spend a lot of time trying to get a few spots within gamut, at the expense of the overall image color.

The human eye has poor density acuity over small distances (< .2 deg view angle) and even poorer color acuity. For this reason we are concerned about gamut only when significant areas of an image are involved.

Assuming normal image complexity, a L*ab difference of 5 is readily perceptable but only with areas that are large enough within an image. It's quite hard to see that large a color change in a 1/16" area of an 8x10, yet there often is well over 100 pixels there. A L*ab difference of 10 is as difficult to percieve in a 1/32" area.

Rather than obsessing over out of gamut colors that may not really matter one way to get a quick view of what to ignore and what not to ignore is to create a duplicate layer. Select it, do a 5 to 10 pixel, (2-5 for B&W) gaussian blur then do an out of gamut check (ctrl-shift-Y). The grey masks will then be in areas that are sufficiently large to consider adjusting for.  A lot of the grey "clutter" vanishes and what is left is the stuff thay can be worth looking at.

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