Techniques of image processing are now accessible with personal comput
ers. The initial phase of the processing is the digitalization of imag
es. It can be achieved by the capture of a video signal, with a scanne
r or with a photographic CD. Digital images can undergo various proces
sings (modifications of the pixels, filters, false color, superpositio
n of images) whose purpose is to improve the quality of the documents
or to show some details. It is fundamental for scientific documents to
avoid the modification or the loss of the information during the proc
essing. Techniques of image processing are going to know many applicat
ions in the exploitation of biological photographic documents.