The decoration of the covers includes three pigments filling lines engraved with a sharp pointed instrument, which now appear as two shades of yellow, one bright and the other pale, and a dark colour that now appears as blue-grey, but was recorded as blue in the earliest descriptions. The front cover includes all three colours, but the pale yellow is not used on the back cover. The pigments have been analysed for the first time, as one benefit of the purchase of the manuscript by the British Library, and identified by Raman spectroscopy as orpiment (yellow) and indigo (grey-blue).BL online page, "The lines of the left board are filled in yellow (orpiment) and grey-blue (indigo)". This is covered in the 2015 book The balance of the designs on both covers is now affected by what appears to be the greater fading of the dark blue-grey pigment.Brown (1969), 14–21 The bookbinder Roger Powell speculated that the "pale lemon-yellow ... may once have been green", giving an original colour scheme of blue, green and yellow on the red background,Battiscombe, 370 although the recent testing suggests this was not the case.
