As a counterpoint to the exploration of colour at play in After Image, the third volume in the colour series is devoted to colour at work. The colourful aspects of each of 17 occupations, including architect, optical scientist, printer, dyer (of fabrics and paper), ophthalmologist and chemist, are presented through a brief essay and illustrative examples: silks threads dyed with crushed bugs, an interpretation of Le Corbusier's colour clavier, paint samples and hair swatches.
The book is standard in size (7 x 8.5 inches, 45 pp.) and overall design (conceived by Barbara and set in Fournier, bound by Claudia with leather and paste paper, boxed with various accessory items, including an equilateral prism) with the first two volumes in the series. This, however, is the first volume to actually be printed (on dampened Arches paper) by Rollin Milroy with the handpress at Heavenly Monkey. This resulted in the sheets emerging from the studio at a much slower pace than the volumes that were printed on David Clifford's Heidelberg, but it was a pace closer to that at which Barbara was able to then complete the extensive amount of painting, embellishing and construction required for each copy.
As with the previous titles, the edition is limited to 30 numbered copies, with the first eight forming a deluxe issue. Each of these eight copies contains an original colour analysis of a different historical work of art. The colour analysis process is based on the work of Emily Noyes Vanderpoel, as found in her idiosyncratic book Color Problems (1901).