Specular highlight control during print copying

[DougBG]

I was elected by family to copy pre-1900 photographic prints and some verrry old oil paintings.  Used Tota hot lights, polarizing gels and standard lighting setup for such work.  Some of the surfaces are rough enough to create a zillion points of light. These highlight points are not noise in the traditional sense but reflections from tiny bumps in the surface.  Polarizing does not help much, and there is a limit to the shallow angles of the lights. I need help to knock down these annoying little reflections.  CS3 noise routines do not help. Anybody??

[sesshin]

I know exactly what you mean. I've encountered that issue before but never had it solved. Polarizing is supposed to help but obviously didn't in your case. Are you cross-polarizing the lens as well as the lights?

Another option is to use a very long lens and back up pretty far. Supposedly the further you back up the more specular highlights are reduced.

Other than that you could try to select the specular color range in photoshop and fill it in accordingly, or use to the stamp or healing brush to clone it all out, but both of those would probably be extremely time consuming.

[DougBG]

I didn't use a polarizing filter on the lens, just the lights. Shutter speeds were pretty slow already.  Maybe I'll have to reconsider. Cloning and healing are, as you suggest, Very tedious.  It's hard to find clean areas to sample as well.  I have tried selecting one area at a time and then sampling and replacing the color of the highlight points, increasing the tolerance as required to get the job done, but this is not a perfect result.  I shot the paintings from 20 feet.  Can't get much further.  arghhh

[sesshin]

Well definitely try polarizing the lens as well as the lights. I think you'll find that reduces the highlights once you rotate it to the right angle. Cross-polarizing does also reduce your overall light output by quite a bit, but my only workaround for that is to use more light if possible.

[ericstaud]

I was elected by family to copy pre-1900 photographic prints and some verrry old oil paintings.  Used Tota hot lights, polarizing gels and standard lighting setup for such work.  Some of the surfaces are rough enough to create a zillion points of light. These highlight points are not noise in the traditional sense but reflections from tiny bumps in the surface.  Polarizing does not help much, and there is a limit to the shallow angles of the lights. I need help to knock down these annoying little reflections.  CS3 noise routines do not help. Anybody??
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Polarizing the lights alone won't do much.  If you throw a polarizer on the lens it is shocking how much reflection is removed.  Make sure the filters on the lights are oriented correctly, then turning the  polarizer on the lens will increase or decrease the effect.

[AlanG]

Why not simply use large soft diffuse lighting?

[ericstaud]

Why not simply use large soft diffuse lighting?
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It would make big milky highlights on the art instead of small specular ones.

[joedecker]

I photograph a lot of paintings for local artists, and you really need both the light gels (in the same orientation) and a polarizer at the camera.    I usually have my lights about 30 degrees off the plane of the artwork.

[AlanG]

It would make big milky highlights on the art instead of small specular ones.
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I think soft lighting will work for what he is doing. He says he is only copying the photos for his family. Soft light should be good enough. This isn't a case of copying for exacting reproduction.  Basically he just needs to shoot them in the shade or with some other kind of soft even lighting.

It has worked for me many times. My mother, sister and her husband were all artists working in oils.  I just looked at an old oil painting in my home under soft light from a skylight and it looked very nice. I'm sure it would photograph well under that light. And maybe the OP's paintings will too. (None of us have seen them or his results, so we can't be sure what is going on.)

[DougBG]

Thanks for the input everyone. I'm resigned to the fact that an additional polarizing filter on the lens will be necessary.  I'll just have to deal with the 2 stop penalty.  That should cure any future problems.  Only wish there was some miracle routine for curing the problem on the images already recorded. Live and learn.