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Discontinuous color table


Gabriel Landini

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The Glasbey lookup table (LUT) is a color table structured in a maximally discontinuous manner. That is, adjacent color bins are chosen to be as distinct from one another as possible.

Like other LUTs, it is available from the ImageLookup Tables menu.

The LUT called “glasbey” uses white at the first index, whereas “glasbey inverted” starts with black.


The Glasbey LUT has numerous uses. It is ideal when coloring a “labeling” of integer-coded regions, since each region will then appear obviously distinct:

JPEG artifacts

Glasbey can also be used to illustrate otherwise-subtle phenomena such as JPEG compression artifacts. Here is a comparison of the Boats sample image before and after being resaved as a JPEG:

The grayscale LUT makes it very difficult (for most people) to see any visual difference. The Glasbey LUT makes it quite obvious where JPEG compression caused a loss of data fidelity.


The Glasbey LUT is based on the publication:

Glasbey Chris, van der Heijden Gerie, Toh Vivian F. K., Gray Alision, “Colour displays for categorical images”, Color Research & Application 32.4: 304-309 . .