One of many things I enjoy is practicing primitive skills; things like making stone axes, throwing atlatl darts, flint knapping, hide tanning, etc. It has given me insight as to what is possible when you don't have modern conveniences and tools. While doing some research online, I found a couple of sites with a wealth of information along the same lines that might be useful for color description if nothing else. The two sites are:
http://www.lowtechmagazine.com/
http://www.notechmagazine.com/
I hope you find them useful.