Multispectral imaging - Infrared False Color (IRFC)
Analytical technique description:
With the introduction of digital photography this technique has become a post processed technique. It could be used for identification of pigments and materials.
The importance of this technique is the opportunity to obtain an image hold information both visible and near infrared range, the last one invisible to naked eyes. So pigments look the same in visible region, but with different chemical composition, can be differentiate by their different behaviour in infrared range. A typical case is the difference between lapis and azurite.
Applications:
Pigments on every surface such as fresco, canvas, marble and wood.
Basics:
Infrared is superimposed on visible image. In visible image RGB channels are shifted, replace blue channel with green and green channel with red. The red channel is replaced with infrared image. In this manner a false colours image is obtained.
Instrumental details:
Canon EOS 400D,  graphics editing program (Florence Unit).
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Institute for the Conservation and Valorization of Cultural Heritage