Board Thread:Questions and Answers/@comment-24865336-20150610214031/@comment-24739388-20150831122034

to go from the 5-bit colors to their 8-bit equivalents, you simply need to shift right by 3 (and in the case of green you shift by 2 since it's 6-bit). This is how it's done in PTC, the lower bits are simply ignored.

A greater issue is figuring out the correct bit order in the actual COL files.