The hardest part is the lighting because any reflected light off the shiny parts of the painting surface will cause problems. The best lighting to counter reflection is cross polarized light. That is, polarize the light source in one direction with a cross polarizer on the lens. You can order "Linear Polarizing Laminated Film" in sheets to use on the light sources. If you use flash, keep some distance between the polarizing film and the flash head or else you may bleach out the polarizing film. The cross polarization should greatly reduce the effect of reflected light off the painting. It is a common technique used in macro work. See for example:
http://www.naturescapes.net/042004/wh0404.htm I have used this technique, ordering the film from Edmund Optics. I forgot to back off the distance of the flash tube to the film and bleached out the center after just a few shots. The cross polarization reduces the effective flash light by a lot, 5-8 stops, so the flash will typically do a near full dump. If the paintings have surface texture then at least two lights angled 45 degrees to the painting will help. The other issue will be lens distortion. I'm not that familiar with Canon glass to recommend which will give the best flat field performance. You may want to experiment with your lenses first, picking the one the is easiest to correct in PS. Stopping down will help with corner resolution. Stopping down while using cross polarized flash will typically cause a full flash dump. Studio lights will be more ideal. Accurate color reproduction is, well, good luck. I suggest testing white balance and perhaps add a color chart next to the painting with some test shots to help with color correcting the main shot. I have used some scanner calibration targets, the best price coming from: http://www.targets.coloraid.de/ Again, realize that reflected light off the surface of the target is the same problem as with the painting. I have been experimenting with cross polarized flash light with portraits. I never liked seeing the photographers complete flash and lighting setup reflected in the eyes. So I wanted to see if I could minimize the amount of flash reflected in the eyes, as well as shinny parts of the skin. The large loss of light though cross polarization is the main limitation, and the burn out on the polarizing film from the intense flash burst. I wish I understood how ETTL II flash worked better. I have not found a reliable exposure mode. Wayne * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
