Infrared reflectography is the most effective technique for revealing the presence of preparatory drawings made by the artist on the ground preparation layer and covered over by paint layers. In order to carry out this type of investigation, the painting is illuminated with everyday incandescent lightbulbs that are attached to a tension transformer and positioned before the work. The rays reflected from the painting are measured by a videocamera modified with a vidicon tube sensitive to I.R. rays up to a wave length of 2,000 nanometers having a sensitively peak at about 1,300nm. This instrument also has a filter that can limit the illumination to a specific I.R. band. The signal is converted into a black and white image that is immediately visible on the screen of a normal high-resolution television monitor. At this point, the registration of the images can be made by photographing the monitor with a still camera or by registering the sequences on a magnetic tape. It is also possible to digitalize the image directly onto a personal computer equipped with a video card.