Basic Lighting Setup for Digital Cameras
Although some advocate using scanner technology to digitize flat art, I have found that modern high-end cameras do an excellent job.
You’ll find that this article is fairly detailed. Believe me, once you have practiced this a few times it will become second nature. And, once your setup is complete, you can shoot piece after piece in short order.
Elements that are important to success include:
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•Camera, lens, and digital sensor/digital back
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•Color-balanced lighting (strobes or continuous) with appropriate soft box or light diffusers
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•An accurate hand-held light meter
I normally use a high-end medium format camera with a digital back, or a view camera that accepts a digital back. These devices are normally capable of RAW capture in 16-bit color depth.
A prime-, or fixed-focal-length lens is best. Avoid zoom lenses, however convenient. Image quality will suffer. Lenses that I have tried with good results in medium format include a 100mm f/2.2, 80mm f/2.8, and a 120 Macro (this is a flat field lens). Of these the Macro is the sharpest; having said this, all of these lenses are very sharp, and have great color fidelity.
It is possible to use a high-end DSLR, such as the Nikon D3, or the Canon 1Ds MkII. The new Nikon 105mm macro is tack sharp. These cameras shoot in 14-bit, and may have some limitations. However, for practical purposes these will work quite well.
A schematic of a basic lighting setup is provided below. I suggest you use identical lights in a room or space which provides for control of outside or ambient lighting.
We will assume that we don’t have a copy stand to work with, so we will use equipment on hand. Set the artwork on a sturdy oversized easel. As much as possible, set the easel up with a minimum of backward lean, and with the bottom of the easel parallel with the floor. Make sure the easel is square to the camera position.
Set up the lights one at a time. Use a soft box or a good diffuser to avoid hot spots. Aim the light as shown above. Set up one light as the master, and connect it to the meter using a PC cord or wireless trigger. Set the other light on “slave”. Leave this light turned off for now.
If your meter has a 3D dome, retract it as indicated for copy work. Use the meter to measure exposure on the easel left to right, and top to bottom. Keep the meter parallel to the artwork. Swing, tilt, or adjust the distance of the light(s) as needed to make illumination even.
Do the same for the second light. At this point, take exposure measurements every inch or so, working left to right across, and also top to bottom. You literally want to check exposure on every square inch of the illuminated artwork. Exposure should be within +/- 1/10 of a stop at each point (that’s right, 1/10 of a stop.) I typically set up the lighting so I can shoot between f/11 and f/16 at ISO 50 or 100.
Again, swing, tilt, or adjust the distance of the light as needed to make illumination even. Adjust one light at a time, meter, and adjust as needed. You may find, paradoxically, that a hot spot on the left side of the artwork, as viewed from the camera position, is being cause by the light on the right!
Set your camera up on a heavy tripod or studio stand. The center of the lens should be at the same height as the center of the artwork as mounted on the easel. If the easel tilts back a bit (it usually does) tilt the camera on the tripod or stand so that the plane of the sensor is parallel to the artwork. Again, make sure that the artwork is square to the camera and the plane of its digital sensor.
There are several ways to check this: one is to step back to the side of the set and compare the angle of the camera to the angle of the piece. Another method is to use the camera viewfinder - if you almost fill the viewfinder with the piece of artwork, you can easily see if there is any distortion or tilting - the rectangle or square will keystone in one direction or another. Make small adjustments in the camera until you are satisfied.
If later on you notice some small flaws, these can be adjusted using perspective controls in Photoshop.
Next, before you forget, take a quick snapshot of the setup - this makes it easier to replicate if needed.
Make sure your camera is on Manual exposure, and dial in the settings indicated by the meter. Place a digital gray card or Color Checker chart in the first frame to help with color management later on. Always photograph artwork using an uncompressed RAW file. Use a lens shade.
Make an exposure of the artwork and check your histogram. It is critical to your success that the histogram “mountain” stays in the middle. If necessary, adjust the camera in 1/3 or 1/2 stop increments.
Now the serious work begins. Shoot each piece of artwork, and use bracketing; typically at meter, minus 1/3 stop, and above meter 1/3 stop.
If you have more than one piece, simply remove the artwork from the easel, mount the next piece, and shoot. Lather, rinse, repeat!!!
If you accidentally bump the easel, lights, or camera (please avoid this!) refer to the snapshot you took earlier to reposition. Meter the piece again for safety’s sake.
A final thought: a really large piece of art, or even a wall mural, can be photographed in segments, and stitched together in Photoshop - much like a panorama.
