The shade card (colour palette) was created using a first edition cover acquired from a shop in Brighton. The envelope / stamp was scanned and then manipulated in GIMP. The day of issue was ’18 Oct 1972′ in Croydon, Surrey.

A quote from The Book in the Cathedral by Christopher de Hamel:

“The colours in the [manuscript] border include yellow, coppery green (which has a tendency to flake), orange-red and an intense deep blue. Recent analysis of the manuscript by Raman spectroscopy has revealed that this last pigment is Egyptian blue, that bright turquoise colour made uniquely in ancient Egypt by fusing sand with calcium and copper compounds at extremely high temperature and used for the famous blue glaze on figurines and ushabtis. It has been identified in about half a dozen Anglo-Saxon manuscripts, almost all from Canterbury. Somehow the monks there had access to an original Egyptian antiquity, from which they must have scraped the glaze and then ground it up for re-use as pigment.”

Related
Weekend 308.0 (Allucciolato)