Appendix: Creating and Editing Color Lists by Hand

A simple CGATS-style color list can be easily created with a worksheet program (such as Excel) or using an ordinary text editor. This is essentially a text document with a few code words at the beginning and end, with the list of Lab values in-between.

Below is an example using Lab values. Note that:

All fields should be tab-delimited.
The header needs to have data format information.

CODE

BEGIN_DATA_FORMAT
Lab_L Lab_a Lab_b
END_DATA_FORMAT
BEGIN_DATA
91 -2 96
44 -29 2
END_DATA

Feel free to copy and paste the code above and use it as a template for your data.

CGATS (ANSI-CGATS.17-2009) is the standard that defines how this relatively simple text file is constructed. As it’s easy to create and edit in Excel and export to tab-delimited format or also open in other text editors, it’s quite common in the color world.

CxF is a more modern XML-based text file format that is quite robust and, being XML, more reliable to exchange between software and third parties. It’s defined in ISO-17972-1-2015. While it is a text file and still somewhat human-readable, it can be cumbersome to edit by hand or import and export from Excel. For this reason and also due to sheer technical momentum, the CGATS format remains popular.

ColorThink 4 opens and saves both CGATS and CxF-format text files.

More more information, a CHROMiX newsletter article on creating and editing color lists is here.