Art Photography by Travis
I'm Kathryn's husband, Travis. My day-job is physics, but I'm also an amateur photographer. Since we got a digital SLR camera last year, I've done all the photography of Kathryn's finished paintings. (Kathryn takes the progress photos for her blog using a simple point-and-click digital camera, but large, high quality images are needed for prints.) There was a request a little while ago for information on how to take photos of paintings, so I'll explain my technique.
If your artwork is small, you can scan it using a flatbed scanner. However, for paintings bigger than 11x14", it's hard to find a scanner large enough, so photography is the best option.
The goal is to produce a digital image that reproduces the original's color, texture, and contrast as closely as possible. I'll start by talking about the equipment I use. If you don't have all of this equipment, just do the best with what you have. The only truly essential things are a camera and a tripod, and a basic tripod can be had for about $25.
Equipment
1. Tripod—absolutely essential for getting clear pictures, especially indoors.
2. High quality camera with manual control of aperture setting (a digital SLR is ideal). Lens quality is less important than the quality of the camera itself, since you can stop down to a smaller aperture to reduce optical aberrations.
3. Remote shutter release (optional), to reduce camera shake caused by depressing the shutter button.
4. Bubble level, to assist in aligning painting and camera.
5. Neutral white card or piece of paper, to help get the white balance right.
6. Two or more movable full-spectrum lights (incandescent lights work well).
7. Polarizing filter for the camera lens (optional), to reduce glare.
Setting up
1. Place the painting on a wall or an easel, and use the level to make sure it's perfectly vertical and level. You don't want it leaning forward or hanging crooked, as that will make it harder to align the camera and tripod.
2. Set up your tripod and camera at a distance from the painting such that the painting almost fills the frame when viewed through the viewfinder. If you have a zoom lens, you'll have more freedom in positioning your tripod, but you'll usually get the best results if the lens is somewhere around the middle of its zoom range.
3. Set up your lights. A good arrangement is one light on either side of the painting, shining at a 45-degree angle to the painting surface. If your lights are very bright or you're having trouble with reflections or glare on the painting, try "bouncing" the light off a flat white surface, such as a large canvas, to make it more diffuse.
4. If you have one, attach your polarizing filter to your camera lens and adjust the polarizer angle to minimize the glare from the painting surface. It is usually easier to determine the correct polarizer angle by looking through it before attaching it to the lens. If your lens filter mount rotates significantly during focusing, you may need to re-adjust the polarizer after focusing.
5. Choose appropriate camera settings. (The following assumes you're using a digital SLR or a digital with a high degree of manual control. Ignore any settings not relevant to your camera.) Choose the highest resolution and image quality available. Set the camera to Aperture Priority (Av) mode—the camera will usually do a reasonable job of calculating exposure. If your painting is mostly dark with a few light spots, try setting an exposure compensation of -1/3, and if it's very light with a few dark spots, try +1/3. If your camera will shoot in RAW format, use it. If not, it's important to pick a white balance setting appropriate for the type of lighting you will be using (don't rely on the Automatic White Balance). Select the lowest ISO value available, which is usually ISO 50 or ISO 100. Set the lens aperture to about two stops below its widest setting; if you're not sure, f/8 is a good bet. If your camera has a built-in flash, make sure it's off. Finally, if you will be using a remote shutter release, set it up.
6. Align the camera vertically and horizontally with the center of the painting. Imagine a line passing through and perpendicular to the center of the painting; the line should pass through the center of the camera lens. To do this, first make sure the camera is level, then adjust tripod height. Move the tripod side to side as necessary. If you have the camera off-center and compensate by tilting it, the image will be distorted.
7. Check the camera viewfinder. Each side of the painting should be near to and parallel with the corresponded edge of the viewfinder frame. If not, adjust the alignment.
8. Once everything is aligned, place a neutral white card or piece of paper beside the painting, so that some part of it is "in the frame" (visible through the camera's viewfinder). This will serve as a color reference later.
9. Take the picture, using a remote shutter release if available.
Post-processing the image
1. Import the image into an image processing program, such as Apple Aperture, Adobe Photoshop Lightroom, Adobe Photoshop, or Canon Digital Photo Professional. If you shot in RAW format, make sure your program can read RAW files from your camera. If you have a newer camera, you may need to install a software update to allow your software to read its particular type of RAW files.
2. Adjust the white balance, using the white card as a reference.
3. Crop the image to retain only the painting itself, and not the surroundings.
4. Adjust the exposure or "levels" if the image appears too dark or too light. If your software will display an image histogram, use that to try to obtain a well-exposed image that is neither too dark nor too light, and does not have clipped highlights or "crushed" blacks.
5. Enjoy your images!