Infrared Photography

Infrared radiation that falls within the range of 780-3000 nm (near infrared or NIR) can penetrate the paint layers of works of art on canvas and paper due to its lower energy. This lower energy (longer wavelength = lower photon energy) is responsible for the lack of interaction with most pigments and paint layers. Essentially, most paint layers are invisible to IR!

This technique is particularly useful for revealing carbon-based preliminary sketches, underdrawings, or other changes that might have taken place beneath the paint layers and which would otherwise be invisible to the naked eye. Digital cameras used in infrared photography are sensitive up to a wavelength of about 1000-1100 nm.

You should note that Auto Focus does not work with infrared photography. In this case, make sure that you have already focused on your object under visible light and have switched off the Auto Focus. You do this by rotating the dial found at the front of the camera to the “M” position before proceeding.

Once you place the B&W 093 filter on the camera, visible light will be blocked and only infrared light will be recorded by the camera. Work out your exposure by taking a couple of test photographs. Once you have done so, slowly rotate the focusing ring clockwise by a notch (usually a millimeter or two) and take one photograph each time you turn it. After about 5 photographs one of them is bound to be the sharpest one. Please, remember to check your IR photographs on the computer before taking the camera off the tripod.

IR light photography procedure

1. Position your object on the electronic easel.
2. Set up your tripod and camera (in the case of infrared photography remember to use the Fuji S3 Pro Camera).
3. Remember to correct the white balance accordingly.
4. Make sure that the camera’s programme is set to “M”.
5. Use Auto-focus to focus on your object (make sure that the dial at the front of the camera is set to “S”).
6. Take a photograph or two of your object.
7. Without moving the camera and/or the tripod turn the dial in front of the camera to the “M” position.
8. Place the B&W 093 filter on the lens of the camera. The B&W 093 filter blocks off all visible light and only transmits IR light into the camera.
9. Position the infrared lights at the 30° or 45° angle mark.
10. Plug in the lamps. Ensure that the cables do not pose trip hazards!
11. Switch on the safelight.
12. Adjust the lamps’ position and/or angles accordingly.
13. Before re-focusing on your object make sure that you take a number of photographs in different exposures to determine the best one.
14. When finished, unplug the lights first, then switch off the safelight.
15. Wrap all the cables around the hooks on the lamps (do not bend or twist the cords!).
16. Place the lamps back to the edges of the room where you found them.