Artwork Photography tutorial: Cross Polarization
One of the more challenging aspects of good artwork photography is accurately reproducing your paintings, free from glare or shine. This is especially a problem for oil painters, artists working with resin coatings, for glossy surfaces, and pre-varnished works. The basic advice often given for artwork photography is to set up your lights at a 45 degree angle from the artwork, and start clicking. Works perfect, but only if you are shooting pieces that have no texture, are perfectly flat, and have no gloss or shine. For those painters working with texture, or shinier surfaces, especially historical artworks that may have a heavy varnish layer applied, the standard advice will leave you with visible glare and washed out areas. The answer is to cross-polarize. Cross polarization is a technique where a polarizing filter is applied to the lens, and over the light source. This allows the photographer to control the light and eliminate all glare from the surface, preserving colours and saturation in the darker areas of the artwork.
Digital SLR/camera that can accept a lens filter
I recommend using a cable release if you have one. If not, use the self-timer function on your camera so that you are not physically touching the camera during the photo. This will help to remove any sources of movement or vibration.
It is necessary to match the white balance on the camera to that of the Halogen bulbs. Different bulbs have a different Kelvin rating (Kelvin is a scale which is used for colour temperature. Daylight is 5600K, while incandescent lights are often 2800K) The bulbs I use came with an information sheet that lists the output as 3000K. This ensures better colour accuracy in the final photo.
With a camera mounted on a sturdy tripod, lights should placed at a 45 degree angle from the artwork. Ensure that the artwork is level with the camera, and that the centre of the lens is directly in the centre of the artwork. I recommend using a measuring tape, to measure from the floor up to the centre of the artwork, and then raise or lower your camera to match the same height. This will help to ensure that the artwork is square within the frame of the camera.
This painting exemplifies the challenge in photographing shiny, dark paintings. This painting from 2004 was varnished, and quite shiny. The dark areas are especially prone to showing glare and reflections.
Image 1 – no Polarizer on the lens, and no polarizer on the lights. Lots of glare, and washed out areas.
Image 2 – Polarizer on the lens only. Reduction in the glare, but not perfect.
Image 3 – Cross-polarized. Polarizer on the lens and on the lights. Glare eliminated, success!
March 24 2018 Posted by Peter Harris