Infrared (IR) reflectography is a non-destructive optical technique for the analysis of painted surfaces, and particularly of ancient paintings on panel or canvas.

The technique allows the recording of infrared images, called reflectograms, having the aspect of black-and-white images.

By analysing the reflectogram, the drawing made by the author on the ground layer (the underdrawing) may be read.
This is due to the transparency of the paint layers to the radiation in the near infrared, that is to radiation having wavelengths in the range from 1 to 2 microns.
Art historians nowadays use this method widely, indeed it turns out to be mandatory to obtain precious information on the author's technique and the graphical means used to draw.
Other important data can be found using this technique, among these are: writings, signatures and dates, originally under the paint layer, or covered by restorations done before the reflectography.

In other cases the analysis of the reflectogram reveals significant variations in the composition of the artwork with respect to its final version, or pentimenti of the author, and even sketches of objects without any relation to the painting as it is seen today. Reflectography is often used also by restorers. In many cases it eases the analysis of the creative genesis of the artwork and reveals previous restoration actions. IR reflectography is performed by using various devices.


IR Riflettography