When one views a
painting, one sees the final piece that the
artist envisioned. One does not see the
shifting in the artist as he created a piece. With
Infrared Reflectography(IRR), that is changed. It is a technique that sees through the upper layers of the painting, reflecting off of subsurface
pigments. It shows the earlier versions the artist thought about. You can see what the artist originally intended in some cases, and see what he added. Find an extra tree perhaps, or maybe the change in position of a person, from sitting to standing. Adding something here, or deleting it there. You can get a
glimpse into the
process of the artist. See some of the things through his/her eyes if you will. IRR is one way to
peel back the layers and see the painting on another level. Important information can be gathered by
historians like signatures, writings, dates that appear under the painting itself. It is often used by
restorers analyzing a piece.
Infrared light can be used to see "through" the painting, so to speak. It can detect the underdrawing, the sketch before the paint is applied. Infrared has a longer wavelength than visible light. IRR can detect wavelengths up to 2000 nm. It's set up as a closed-circuit television system. Photographs are taken of the television screen, reflectograms which appear like black and white photographs. Then pasted together to form the image of the piece.
Underdrawings in black chalk or bone black will appear dark because they do not reflect infrared. Only a small portion of the painting can be looked at at a time because of low resolution.
This is used in conjunction with X-Radiography, another method of peeling back the layers, to see more of the painting. Two techniques to see different layers along side the original. Suddenly the painting becomes more than it was, more than it is. It becomes three dimensional.
To see an example of this go to the Getty Center in Los Angeles, California. An exhibit of "The Miraculous Drought of Fishes" by Joachim Beuckelaer (1563) is presented with the painting along side of the X-Radiography print of it and the Infrared Reflectography print of it. It runs until August 19, 2001. Three versions of the same work of art. It's like seeing a ghost image, the bones of the painting. As close to seeing through the artist's eyes as you can get. Breathtaking.
info gleaned from various sites including:
www.artmuseums.harvard.edu/Renaissance/noframe/nIRR1.html
www.ino.it/~luca/rifle/rifle_en.html
www.getty.edu/art/exhibitions/renaissance_paint.html