Photographing paintings behind glass

You could use a good zoom lens and stop it down to f/8 or f/10 and it will be as relatively sharp as most primes. Zoom in and out as necessary for different sizes. The same skew (the correction is really called keystone) would apply to all shots as long as the camera and mount for the art remain at the same position.


Color temp stays the same regardless of exposure. I think someone already mentioned getting a Color Checker. I use the Passport version. Subject matter is irrelevant to color temp.

DaveC426913 wrote in post #18656486
Is this a camera setting?

I wonder if it will be preserved across a range of exposures, as I shoot various sizes, having to zoom in or out as-needed. I guess as long as I don't move the lights themselves, the exposures should remain constant.

Will it survive changes in matte? i.e. a white matte will have an overall reflection brighter than a navy matte.
(Though I'll be cropping the mattes out.)

Yes, it's in your manual.
It has to do with the color temperature of the light, as in warmth/coolness. It has nothing to do with the exposure.

Personally, I would remove each from their frames. Time consuming? Sure, but that's the right way to do it. Ultimately it's up to you though.

Technically, though, if you watch your angles, you shouldn't get glare from the lights. Your biggest issue, I think, is avoiding shadows from the frames and mats. If you keep your light back and to the sides you should be able to light the artwork evenly. As for reflections, I've had really good luck shooting through a piece of black foam core with little to no reflections visible. And you don't need a totally dark room either. And yes, you can (should) shoot perpendicular to the artwork. That will save you hours in post processing.

Since you're shooting framed pieces, consider rigging up a frame holder similar to an artist's easel up on a wall. This will allow you to easily adjust each frame to center on the camera. You can then move your tripod closer or further as size demands without constantly having to adjust camera height.

Just some suggestions.

I highly recommend this short video: https://www.youtube.co​m/watch?v=XG2VY2vxFhc
P.S. Have a good polarizer is a great idea too.

Links are in:
Shooting artwork(paintings)
includes:

Given the years of labor and skill and talent already invested I'd be inclined to produce the best possible digital copies to serve not only for the book but also for potential art prints. For me that would mean buying, renting or gaining access to a large format scanner. Modern graphics scanners produce excellent images. Most of the usual suspects have wide format options. I've used a Colortrac SG 36 and was flat amazed by the results, but other vendors may be as good or even better.

After many years of copying glossy originals & thru glass I can only add to what has been said already by suggesting the following. If possible, polarize your lights both in the same direction. Then polarize your lens in the opposite direction. For instance, Vertical on the lights & Horizontal for the lens. I don't know what a circular lens polarizer would do but I imagine it would work similar.

Tixeon wrote in post #18657015
After many years of copying glossy originals & thru glass I can only add to what has been said already by suggesting the following. If possible, polarize your lights both in the same direction. Then polarize your lens in the opposite direction. For instance, Vertical on the lights & Horizontal for the lens. I don't know what a circular lens polarizer would do but I imagine it would work similar.

For this work a linear polariser would I think be fine. It shouldn't be an issue since I would not expect to be using the AF anyway. You could use circularly polarised light, with the illumination and camera filters "crossed" too, I don't know how hard it would be to find CP gels for the lights though. The issue may be that linear polarisation is easily available for the lighting, and CP is what you find for the camera, and mixing linear and CP won't work.

Alan

Alan, I don't do much copying anymore but I always used linear polarization for both lights & camera. So far, I haven't run into an auto focus issue with digital and the linear polarizer on the camera. Not sure why, but it just works.

-Duck- wrote in post #18656659
Since you're shooting framed pieces, consider rigging up a frame holder similar to an artist's easel up on a wall. This will allow you to easily adjust each frame to center on the camera. You can then move your tripod closer or further as size demands without constantly having to adjust camera height.

Thanks. This is a good idea. Mount them all on the same axis, son's'n I don;t have to adjust the camera all the time.


I went out and bought 2 rolls of landscape fabric, a handful of clamps, and two daylight-balanced fluor. lights.

Time to experiment.

DaveC426913 wrote in post #18657612
Thanks. This is a good idea. Mount them all on the same axis, son's'n I don;t have to adjust the camera all the time.

I went out and bought 2 rolls of landscape fabric, a handful of clamps, and two daylight-balanced fluor. lights.

Time to experiment.

Cool. Looking forward to hearing how it all works out.

For the images that you plan to shoot under glass (to keep them flat) get a piece of non-glare glass. You may also be able to rent or buy or borrow a vacuum easel. The lights and camera should be polarized. Search Rosco polarizing screens.
Use four lights. 250watt flood lights . Work with tungsten and set color balance accordingly. You will need to adjust the angle based on the size of the prints to be copied. Turn off room lights. With everything polarized you should be able to set the camera lens dead center and not get any reflection from the camera. You may even want to consider a Polaroid MP4 copy stand.

vraspagraphix wrote in post #18659293
You may even want to consider a Polaroid MP4 copy stand.

Personally, I find copy stands too cumbersome to use. Specially with larger prints, as the OP implied he has to work with. Working of a wall is much more convenient as it allows for lots of room and flexibility while working at a comfortable height and position.

But that's just me.

vraspagraphix wrote in post #18659293
For the images that you plan to shoot under glass (to keep them flat) get a piece of non-glare glass.

Doens;t non-glare glass interfere with the clarity of the image?

vraspagraphix wrote in post #18659293
Use four lights. 250watt flood lights . Work with tungsten and set color balance accordingly.

Yeah... I bought a couple of daylight-balanced flourescent bulbs from the camera shop at 20 bucks a pop - only to get them home and discover they are a whopping 22w.

22w fluorescent is much higher rating in incandescent, usually 4x. Check the lumens rating.

Hopefully the money spent benifits you via CRI.