When making a platinum print, the addition of palladium yields soft, warm, sepia-like tones. Carbon based pigments give a very similar effect. To compliment these tones, a thick cotton mount board in one of several ‘off white’ shades is selected to match. Quite apart from being acid free, the boards do not contain lignin and are clear of optical brightening agents. They are 100% cotton. Personally, I favour the visual simplicity of a thick 8ply mount, cut with a beveled edge as shown in the picture. A burnishing bone smoothes the edge.
An image made on pure cotton or linen rag and formed from carbon ink or platinum and palladium has an unmatched archival stability. Still, museum specification glass will always be chosen, to block almost completely the most damaging of Ultraviolet Light.