The Problem of Colour

Although photographic reproduction of drawings, architecture and sculpture was done from very early on, paintings presented a particular challenge for the new visual medium of photography. The reason for this was the chromaticity of the objects, which was extremely difficult to reproduce using early photographic processes due to their low sensitivity to colour. The light-sensitive substances used to prepare the negative plates reacted most quickly to blue, in addition to white, while red, yellow and green were absorbed very slowly, which resulted in incorrect translation of the colours to the corresponding grey values. This had fatal consequences for the reproduction of frescoes and paintings: Sections of the picture that were originally blue were depicted in white in the photograph; red, yellow and green appeared much too dark and were hardly distinguishable from one another. This problem is particularly evident in the photographs of the Giotto frescoes in the Cappella degli Scrovegni in Padua, which were taken in 1865 by the Venetian photographer Carlo Naya. For this reason, frescoes and paintings were often photographed using monochrome lithographs that were produced specifically for this purpose. Only after the Berlin photo chemist Hermann Wilhelm Vogel developed a process from 1873 onwards which allowed a significant improvement in the colour-sensitivity of the negative plate, was it possible to achieve more satisfactory results when photographing colour objects over the years that followed.