Spectrum opens with a brief introduction by interior design expert Ros Byam Shaw, exploring the history of colour as used in interiors. The fabrics and wallpapers that follow are arranged chronologically. Each is reproduced on its own double-page spread, and is accompanied by a brief narrative-style caption that provides information about each fabric or wallpaper and its significance in the context of interior design. Unique in such a book are the colour grids shown beside each pattern, in which the colours in the original piece are shown in proportion to their use, and with their CMYK references to enable designers to replicate these colours in their own work.