terrafirmanada said:
I do submit work to gelleries, so it needs to be as close to pro quality as my budget permits.
Okay. I've had no formal training for reprophotography, but a local camera shop/studio owner and professional industrial photographer once gave me a crash course. I've since done a few paintings for some friends. I've also had to shoot some large flat signs and book covers to sell on eBay, and I'm damned fussy. Here's what I've learned really works, and you might not need to spend any money on gridded focusing screens, either:
You will need a carpenter's level, a tape measure, and a patient assistant.
EVERYTHING MUST BE SQUARE AND LEVEL. If you are hanging the painting vertically to shoot it, put a carpenter's spirit level across the lens filter ring and make sure it's straight up and down too. (If the painting is small enough to shoot on the floor or tabletop, use the level to make the lens parallel to the painting, in both axes.)
EVERYTHING MUST BE CENTERED. With a tape measure, find the exact center of of the painting. Put a small piece of masking tape or some other non-damaging marker right there. Now, using the tripod mast, raise the previously plumbed camera until the view through the lens is centered. The center-spot in the viewfinder focusing screen should be dead-on the marker you put on the painting.
LOOK THROUGH THE VIEWFINDER AND CHECK FOR PARALLELISM OF THE TOP AND BOTTOM EDGES OF THE PAINTING. This will show you if the lens is square to painting side-to-side. If the top and bottom visibly converge, you must rotate the camera and
then re-center the tripod. Several corrections may be required. Be patient. (This is where a gridded focusing screen pays for itself. My digital camera has one, and it makes eBay work
so easy.)
NOW (AND ONLY NOW) BALANCE YOUR LIGHTING. If necessary, get the measuring tape out again, and install your lights at the same distances and angles from the painting. A 45° angle is what repro stand lights are typically set at, and there are usually two of them, one at each end if we're talking horizontal format.
Finally, since you're shooting slides, METER OFF A GRAY CARD HELD DEAD SMACK OVER THE CENTER OF THE PAINTING. If you aren't using a gray card for repro
on slides, step away from the bong and go buy one at once. Bribe an assistant with beer to stand there and hold it, if you have to. And, if the painting is very large or your lights are very weak, it may pay off to move the camera around and meter at every quarter of its length, adjusting the lights until you get tolerable variances. (A hand-held spotmeter would help here. If you don't have one, simply take the camera off the tripod without disturbing its setting, and shuffle sideways remaining the same distance from the painting while your lackey crawls along the floor holding the gray card up. (And if you can find a way to do this outdoors in a flat open area on a cloudy day with the painting facing north, you will solve 98% of your potential lighting problems.)
Are you having fun yet? No you're not, dammit, because this is not fine art photography, this is technical photography of fine art, meaning it's boring old
work. But squareness and plumbness and well-balanced lighting will pay for your time.