The cleaning of the Sistine ceiling in the 1980s brought unexpected insights into Michelangelo’s approach to painting. The dirty surface had contributed to the idea that the artist was not much interested in colour and was more obsessed with forms and especially the form of the human nude. Nevertheless, the cleaning revealed what appeared to be unusual colour combinations. In addition to modelling with single hues, from light to saturated, Michelangelo also used different colours for shadows and highlights. The lunettes, however, presented interesting challenges. There, one found especially contrasting colours. The Asa-Josaphat-Joram lunette, for example, features the Asa figure on the left with a cloak modelled from apple green to deep orange and red.

In the symposium dedicated to the unveiling of the restored frescoes, costume historian Edward Maeder interpreted these colours in the lunettes as ‘shot-silk’ – in Italian, cangianti, a kind of silk woven with contrasting colours that appear iridescent when seen in the light. According to Maeder, who had singled out the figures of the ancestors in his arguments, colour changes are used to make these Eastern ancestors of Christ more exotic. While it is true that colour changes have been used to represent shot-silk in Italian painting, Maeder went on to suggest that since this fabric was most commonly available from the Near East, it would carry Oriental associations and therefore serve ideally for the ancestors.

Maeder constructed his argument in a typical art historical way: we see figures that evoke associative meanings. But he was challenged strongly by the English art historian, John Shearman. Shearman had written a dissertation on the colour of Tuscan painters like Michelangelo and emphasised the great artist’s dependence on his teacher, Ghirlandaio, an artist who had practised the Tuscan tradition of ‘isochromatic colour composition’ in the ceiling. This system, according to which broad, flat fields of colour are decoratively balanced along the picture surface, is frankly medieval in origin. According to Shearman, decorative fresco was required to create surface unities to aid visibility even more than making possible narrative associations.

Years later, Shearman prominently titled his contribution to the postrestoration volume on the Sistine ceiling, ‘The Functions of Michelangelo’s Colour’, explaining how the high-key colours were in large part a response to the conditions of visibility, illumination and decoration that Michelangelo was facing.