Glasbey

Glasbey (Discontinuous color table)
Maintainer Gabriel Landini
Source [1] and [2]
Category Category:Color_processing
Glasbey.png
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 Image  ▶ Lookup Tables menu.

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

Labelings

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:

Glasbey-labeling.png

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.

Publication

The Glasbey LUT is based on the publication: