 richard |
photographing oil paintings i need to photograph paintings that hang on walls. the paintings are in oil ,each are at least 6 feet off the floor about 4 or 5 feet high and about 3 feet wide. I use 2 1200 watt flash with umbrellas that has variable intensity. the flashes are about 12 to 16 feet from the paintings at 45 degree angles. I get hot spots on the paintings that wash the color out. can anyone suggest how to set the flash ?
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John A. Lind |
Richard, Was hoping someone who had actually done this would respond . . . but it's been a few days. Here is what I've read about lighting for this and the logic is sound . . . Your flash placement is sound . . . at 45 degrees. The height of them should be the same as the middle of the painting so that all four corners are evenly illuminated. Use just enough light for an aperture of f/8 or f/11 where most lenses are the sharpest. A slightly longer than standard lens is recommended . . . 75 - 100mm (for 35mm format). Some use macro lenses in this length because they are more likely to have a very "flat field." Getting rid of the hot spots on oil paintings can be difficult because they have a texture from the canvas and the brush strokes which cause the glare. Most recommend using polarizing panels on the lights and a polarizer on your camera. Polarizers for lighting come in large panels and typically have arrows on them to show their orientation. Ensure the panels are oriented the same way on each light. Then orient the polarizer on your camera at 90 degrees to the polarizers on the lights (called cross polarizing . . . if the light polarizers are up/down the lens polarizer should be left/right). If your polarizer for your lens is not marked with an orientation you may have to experiment by firing the lights and rotating it bit by bit until the hot spots are gone. When it's right, all reflections from the surface of the painting will be gone. The polarizer for your camera lens can be circular or linear, it does not matter. -- John
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richard |
First thank for your timely & in depth answer. Let me qualify my question.The flash equipment is in Venezuela without chance of expermenting with polarizing panels. I have a 55mm& 135mm plus a 60 mm macro, will try macro. Last year I centered flashes & still had hot spots. I was thinking of turning down intensity of flash 1/8 or lower if possible using maximum aperture not worrying about sharpness due to minimum blowup. Thinking that less intensity will give greater eveness ie less hot spots.Or if possible putting flash units at a greater distance from paintings so umbrellas cast more even lighting? My problem is that my services (as a good photographer) were volunteered. No time to experiment ,retake pictures due to minimum vacation time.Any thoughts on my changing intensity or distance of flashes. Thank you John & whomever else cares to comment.
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Jeff S. Kennedy |
John's advice is sound. I haven't done this either but John's description of how to do it sounds like the way I've read its done. As to your follow up questions: I don't think a lower intensity will prove to be much different, since you will be dealing with the same exposure just at a different aperture. Moving the umbrellas further away will probably make the problem worse not better. Moving them away will make them relatively smaller light sources thereby creating more spectral highlights. Keep them close for softer light. Are the umbrellas diameters larger than the height of the painting? Ideally they should be at least as big as the painting. Do these lights have modeling lamps? If so, eliminate all ambient light and set up the lights until you see no hotspots from the camera position. Be sure to measure the light at all corners and in the center until you get even exposure.
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richard |
Thank you for your responses.I am buying polarizing panels & frames to mount in front of flash. Due to limited time the question is: if I change position to photograph different paintings which might incur different angles of flash doI need to rotate lens ploarizing filter to comppensate for slight change of angle.This is after expermenting with lens polarizing filter to get correct angle on first photo. Appreciate all the help. Richard
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John A. Lind |
A thought experiment . . . thinking about the polarization and light ray paths . . . tells me no. You should be able to verify this on location if you can trigger the strobes while looking through the viewfinder for any hot spots. I would be more worried about maintaining even lighting on each painting as as you move from one to the next though. It's the reason I mentioned keeping the strobe height centered on the painting vertically and illuminating them from each side at 45 degrees. If you've ever done any copy stand work, the basic concepts are much the same as doing it with reflective materials to be copied. The difference is you're aiming horizontally with the material being photographed on a wall. If time is that limited and you can't move the lighting much, then try to find an initial lighting position that will provide something reasonable for all of them. -- John
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