Always in an attempt to establish how much of the surface is original, the technique known as colour infrared can show the results of I.R. radiation as well as a part of the visible spectrum. By using a special colour film and a filter that excludes blue radiation, we can obtain on the photographic image of green, red and infrared radiation reflected by the painting. The film will arbitrarily assign colours: I.R. will appear red in the photo, and the red and green with respectively appear green and blue. This technique allows for further evaluations and will show the difference between apparently similar pigments. For example, verdigris and cobalt green with show up magenta and blue respectively. In terms of pictorial retouching, it is possible that this technique will reveal nothing. Nevertheless, it is also possible that the colour infrared analysis can evidence non-original areas that the ultraviolet fluorescence did not pick up because of the presence of old varnishes.