Glasbey (Discontinuous color table)
Maintainer Gabriel Landini
Source [1] and [2]
Category Category:Color_processing
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.


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: