John Dalton’s Colour Vision Legacy
John Dalton, the celebrated chemist, realised that his colour perception differed from that of others, and he left a detailed description of how colours appeared to him. Dalton believed that his vitreous humour possessed an abnormal blue tint, causing his anomalous colour perception, and he gave instructions for his eyes to be examined on his death, to test this hypothesis. His wishes were duly carried out, but no blue coloration was found, and Dalton’s hypothesis was refuted. However, the shrivelled remains of one eye have survived to this day, and now belong to the Manchester Literary and Philosophical Society.
This large book contains the edited proceedings of a conference commemorating the 150th anniversary of Dalton’s death. An undoubted highlight is the ‘essay in molecular biography’ of Mollon, Dulai, and Hunt: taking samples from Dalton’s eye, they amplified sections of his visual pigment genes, and identified his colour vision genotype (he was a deuteranope, lacking the normal middle wave pigment gene). By measuring the colours of such things as 18th century sealing wax and the leaf of Prunus lauro-cerasus, they were able to confirm that the colour confusions recorded by Dalton are consistent with the genetic diagnosis of deuteranopia.
As a conference volume, there are naturally differences in style, and wide variations in content, which reflect the different interests of the different authors. However, the editors have done a fine job in organising the volume into sections, each containing a number of papers by different authors on related topics. As might be expected, many papers are on colour vision deficiencies and colour vision tests, including contributions from Morland and Ruddock on acquired deficiencies, from Moreland on anomaloscopy, and several on automated colour vision testing. But the scope is much wider than this. There is a good review from Teller on the development of colour vision; there are purely practical contributions, on the prescription of coloured filters for children with reading difficulties, for example, and there are theoretical contributions on models of colour vision and colour constancy, and on chromatic channels and pathways. The book therefore provides discussions of particular problems in detail, rather than a broad coverage of basic principles and techniques in colour science. As such, it will certainly be of interest to anyone doing psychophysical work on colour vision, as well as to ophthalmologists interested in colour vision and colour vision deficiencies, and the excellent index and cross references will make it easy for the researcher to find the articles that are relevant to his or her work.