- Handling: If the painting is large (for example, 30 x 50 inches) it can be both heavy and awkward to handle. It is a good idea to approach handling of a large painting as a two-person project. Removing it from the wall requires particular caution to avoid accidentally dropping it. To protect the painting it is also a good idea to wear a pair of soft cotton gloves.
- What to photograph: In addition to a photograph of the front of the painting, it is a good idea also to take a close-up of the signature inscription as well as any inscriptions on the back of the painting. The inscription photographs can be very useful in authentication.
While you have the painting down to photograph the back, look carefully at the stretcher bars and the frame to see if there are any pencil notations, numbers, or other identifying marks. If there are any, they sometimes help identify a painting with a site, a recorded sale, or a previous owner or dealer.
- Lighting. Photographing an oil painting can be a little tricky, because the varnish is usually very shiny and it will reflect a flash back into the camera.
If possible, avoid using flash by taking the painting outside on a bright, clear day at a time when the sun is high in the sky. Try to find a location where the painting is not directly in the sun, but rather has a full view of the open northern sky behind the photographer. The sky light should eliminate the need for flash (turn it off, if possible), and it also tends to get a good rendition of the color.
It is also possible to photograph the painting in full sun, but check the viewfinder to make sure that the varnish isn't causing a reflection, this time of the sun, from the highlights of the painting. Choose a time and location where the sun is high overhead, rather than coming over your shoulder, to minimize reflections. If you have time, you might try both the open-sky and the full-sun positions to see which comes out best.
- Indoors: If you have to take the photograph indoors with a flash, stand to one side of the painting and shoot at an angle, so that most of the flash reflections bounce off toward the other side. The picture in the photograph won't be rectangular, but that is easily fixed later with digital processing. It may also be worth trying a straight-on shot with available light to see how it comes out.
- Film vs digital: For the purposes of the Schafer catalog, a digital photograph is usually quite satisfactory, preferably the highest resolution photograph your digital camera can handle.
On the other hand, film is also fine. I can work with a print, a negative, or a slide.
- Zoom: Many digital cameras have a zoom lens that is automatically set to maximum wide angle when the camera is first turned on. With that setting, if the photographer stands close enough to the painting to fill the viewfinder, the photograph is likely to show the painting with bulging sides, like a pincushion. To avoid that effect, set the zoom to maximum telephoto and then stand far enough back from the painting to capture it in its entirety.
Some digital cameras have a close-up mode. If so, the combination of close-up mode and maximum telephoto zoom can usually capture a good photograph of a signature inscription.
- Focus: When photographing a small painting or a close-up of a signature, check the camera's distance range and make sure that you aren't holding it closer to the painting than the camera's focus range will allow. Some cameras can't focus closer than three or four feet. A sharply focused picture from a greater distance is more useful than a fuzzy close-up.
- Measuring. Because the frame usually covers the edges of the painting, the best way to measure its size is to turn it over and measure the length of the stretcher bars or the size of the canvas board from the back. Measuring from the back is not only more accurate, it helps ensure that the measuring tape or yardstick doesn't scratch the surface of the painting.