I was asked to do a workshop at Pratt to show some grad students how to photograph art for their portfolios and websites and such. So I’ve spent some time putting together notes for my presentation and figured I’d write it up as a post for those who missed it or as a refresher for those who attended. I’m going to assume some photographic knowledge on how to use a camera and lights and that you how they work and such.
Preparation First things first, you’ve got to get the art ready. Remove it from from any frame or at least remove the glass if the frame is part of the art. Flatten any curled papers by sandwiching them between some books for a while or have them pinned down on the corners so you have a nice flat surface to shoot. Some people use an easel to hold the art, or use binder clips attached to a wall in order to hold it vertically without having to pin through it. I’ve also see artist’s tape attached to the back side of the corners of the art and tacks or more tape the other way used to attach it to a wall. When it comes to 3D art or sculpture, make sure everything is clean and you have a good setting to shoot it in. Don’t forget about the background. You generally want a nice neutral color behind the work if possible.
Lighting When it comes to lighting you may be surprised to find out that you don’t always need fancy lights. In fact, a nice even indirect Sunlight is a great source, nice and soft. In fact it’s what we’re going to try to mimic when we don’t have it available. For best results you’ll generally need quite a bit of light in order to use your camera at the lowest noise and highest sharpness settings.
Flat art and sculpture will generally require different lighting setups because in one you’re trying to minimize shadow and in the other you try to use it to your advantage. That said, even with flat art you may want to light the work more from one direction. Does the work require texture? It may have a surface you want reflected in the picture, things like canvas, finer papers, or the impasto technique in painting for instance.
Once you decide what you’re goal is you can setup some lights. Basically two different options, continuous or flash. The advantage of continuous is that it’s WYSIWYG so you see what the light is going to look like in the picture, and they’re cheaper, however you need to take more care to get the color right and they don’t put out as much light as strobes so you’ll need longer shutter speeds all things being equal. Flashes on the other hand put out nearly perfect light at whatever amount you need, though they’re a bit harder to use in practice. Either way you’re usually going to want to spread the light out to be softer, using umbrellas or softboxes or similar tools.
For most work, two lights is more than ideal, one on each side of the flat work to fill in each other’s shadows. As far as distance goes, because light falls off in an exponential fashion, you’ll get more even light across a larger area if you back the light up a bit. Though this property can be used to the opposite effect in sculpture by using closer up spots to highlight parts of the work. Don’t forget too that even if you have only two lights, you can mimic a third fill light by using a reflector.
So the place to start is two lights, both in front, one on either side for flat objects like papers, canvases, and such. For 3D objects, try one up front right as your main or 'key' light and then a second around the other side and slightly behind to give the left side an edge and some dimensionality. Move and shoot to taste.
Color When it comes to getting the correct color in the photographs you must remember that all light is not equal. The main thing you need to worry about is color temperature. Just like how you’ll notice that things look warmer and more orange with old school incandescent light bulbs, you need to tell the camera what kind of light you’re using so it can compensate. The three you’ll ever probably use are Daylight, Tungsten (fancy name for normal light bulbs) and Fluorescent. Almost all digital cameras allow you to manually set the white balance, called WB on some systems. If you shoot RAW files instead of Jpeg right out of the camera, you can effect the white balance in a computer in post-production. This is arguably the more accurate method, but it doesn’t hurt to get it close in the camera just to see what you’re doing while shooting.
If you’re really anal about such things and color is important to you, make sure you’re on a good calibrated screen and also shoot a color chart or grey cards to give yourself a reference to work with. More on this later.
Camera Don’t forget, you may not need to use a camera. If you’re work is small enough you can get arguably better results from a scanner. You say your painting is 3’ wide? Ok, well read on then.
Even though you may be doing all of this to go on a website at lower resolution, when in doubt work on bigger files. You never know when you’re going to need a high-res copy to sell print reproductions or to give to the authorities when your painting gets stolen from the Uffizi
You can of course use just about any camera, but you we’ll use a dSLR. However in a punch I think you could even use an iphone if you had to. You want to use longer lenses (more telephoto) when possible because it flattens perspective and allows you to move further away from the work so that the likelihood of reflections from the lights is less. Prime lenses tend to be sharper across the frame than zooms, though both can be used. Better lenses also have less geometrical distortions which you wouldn’t notice when taking a picture of your friend on the street, but become very obvious when you’re shooting a perfect rectangle and the sides look like they’re bulging out.
You’ll want to shoot straight on from the middle of the work to reduce key stoning. I’ve also shot straight down depending on size of work. The floor makes a nice flat surface to shoot at.
Exposure Ok, so you’re ready to actually take the pictures. If you can, use a tripod if possible, that’ll make getting the shot straight on and longer exposures possible if you’re using continuous lights. Use the lowest possible ISO, 100 or 200 are great, that will make sure you have as little noise as possible in the images.
If you’re using continuous lights, set your camera to Aperture Priority (“Av”), that way it’ll take care of the shutter speed. Lenses are sharper in the corners if you stop down the lens, so if you have enough light, stop the camera down to it’s optimal aperture, usually somewhere between f/8-f/11, but try to make sure you’re at at least f/5.6 for best results.
If you’re using flashes, you’ll want to shoot in Manual Mode (“M”). Set the shutter speed to 1/160th of second, and stop the lens down to f/8. Back in the day you would have used a light meter to set the power of your flashes, but now with digital you can just as easily take some test shots and adjust the level of your lights to taste.
Use the cameras Histogram to gauge exposure. Make sure you’re nothing is way off either end of the spectrum, though unless your piece is extremely contrasty, you should worry more about not clipping the highlights.
Post-production Once you’ve gotten the shots you need you can use Photoshop or Lightroom to fix geometric and perspective issues. Crop, and use the grey card you shot earlier to set the back, white and grey points to get your color corrected. Often the images will require a bit of sharpening to look their best. Use small radius and don’t overdo it. If you’re sharpening in Photoshop, use the “Smart Sharpen“ filter instead of “Unsharpen Mask” for best results.
Wrap-up Things can get crazy from here. How to deal with translucent objects and reflective pieces, oddball perspectives like shooting from above or below, stitching together multiple shots of a larger work that won’t fit into frame well. Those are all subjects bigger than I want to get into, but I’m sure the stuff above is enough to get your started.