Colour Under the Microscope: Santiago Ramón y Cajal Does ‘Histology’ on Lippmann Heliochromes

Abstract

This paper highlights Gabriel Lippmann’s discovery of colour photography and the microscopic analyses performed upon the photographs by Santiago Ramón y Cajal (1852–1934), professor of anatomy and histology in Madrid, acknowledged “father of modern neuroscience”, and avid photographer, in a historic and a modern perspective. Cajal placed sections of Lippmann photographs under the microscope to study the structure of their materiality. He focused on the laminae of Zenker, which produced mixed colours, especially white. His technical studies culminated in a 1908 article in the Annual Report of the Board of Regents of the Smithsonian Institution and in his subsequent Spanish classic monograph, Photography in Colours, expounding upon the theoretical physicochemical principles and practical applications of the “art of Daguerre.” The authors thus explore Lippmann’s reception in Spain.