What are Color Gamuts? Part One


What are Colour Gamuts? Simply put, a Colour gamut is a whole range of digital Colour that are included in a color profile. Different gamuts contain varied subsets of different colours.

Now, this is a huge subject to cover, so instead of just trying to explain what they are, I will start by comparing two similar gamuts from two RGB profiles: Adobe RGB (1998) and sRGB IEC61966-2.1

Adobe RGB (1998)

Displayed below is a 2D image of the Adobe RGB (1998) colour profile. This is the type of image you’re going to see a lot of throughout this set of articles. Ignore the LAB colour letters (b+, a+, etc) and observe the colour and shape. Notice how all the colours shown radiate from white, denoting the additive colour model.


The next image (below) displays the same RGB gamut but in 3D. This is one of countless views that can be viewed with special software, such as PerfX Gamut Viewer or ColorThink Pro. As can be seen, the 3D view reveals more tones, hues and shades than the 2D version.

Each colour gamut shown is complete with a coloured-boundary, which indicates the extreme edge of the gamut in both 3D and 2D angles. This one, for example, shows this edge in Red.


Comparing Color Gamuts

Now we know what we’re looking at, I’ll start comparing the two colour gamuts. The larger gamut is a representation of the Adobe RGB (1998) colour profile, shown in RED. The smaller profile, sRGB IEC61966-2.1, is displayed in BLUE (just visible).

The next three images show varied angles of the two color gamuts…


Both gamuts displayed are visible at a medium opacity, so you can see both at once.


Notice that even though the Adobe RGB profile is generally larger, RGB 2.1 supercedes it in certain key areas of color…


These areas are primarily in the green/blue region of the gamut, shown above.

There you have it—the introduction to the series of articles about colour gamuts. It would be very hard to cover many aspects of the subject matter in one post, so Part Two will continue the journey shortly. Why not subscribe to my RSS feed so you don’t miss it?

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