Where do you find LEGO color IDs?

[ToastBubbles]

I am aware of the many different LEGO color charts/tables that translate the names and IDs (peeron, brickowl, rebrickable, etc). But where do the LEGO color IDs actually come from? I noticed some inconsistencies while doing research and was trying to verify the correct numbers.

[Lyichir]

Various places. Often these days they're sourced from pictures of official Lego color charts, where 2x2 tiles inscribed with the ID number are arranged in a grid. But there have been other sources over the years as well. LDD used to use the official IDs to identify colors (and editing file data could allow you to access colors that weren't on the "official" in-app palette). And there are probably some sources that I'm not aware of.

Ryan Howerter's color chart is one of the most reliable ones I know, compiling data from various sources and including not just "standard" plastic colors but also some novelties such as the ink colors Lego uses for printed elements.