Long before hexadecimal ever became a household word and the hexadecimal way of numbering colours had been dreamt up, Louis Loynes, one of the founder members of the DSGB, had already created his suggestion for a colour notation based on twelve.
His book, "Byraz Colour Co-ordinating", was published and printed by him im 1959. I don't know how many he printed, and it may well be that I have the only surviving copy. Just in case this is so, I have begun to scan in the pages of the book and turn it into a pdf file. A test version (Byraz01.pdf) - consisting of the first 19 pages (of 132) is at Byraz for you to download and comment on. I have tried to keep the file size as small as possible and would appreciate comments on the reproduction of the pages.