I thought I’d share with you how I photograph my oil paintings. Photographing drawings, pastels or watercolors is pretty easy because the surface is flat and diffuse. Taking good photos of oil paintings however is quite challenging, because of the surface texture and glossiness. It seems no matter where the light source(s) are put, there are a lot of bright specular/direct reflections from the canvas which alter the perceived value of the paint. A dark area in a painting appears too bright because of the reflections.
I have tried different approaches (haven’t found the perfect solution yet though), but I’ve narrowed it down to two setups which work for me:
- Tilted camera approach
- Using cross polarization
I usually try #1 first, but if there are still too many direct reflections, I’ll use approach #2.
First some general things that are common to both techniques:
I use a single lens reflex camera with a medium telephoto (around 100mm or longer) lens. If the camera is too close to the painting, it will see more direct reflections than if it’s farther away. Also, a wide angle lens typically causes barrel distortion, so a longer lens is a better choice.
I shoot RAW, so it’s easy to adjust exposure and white balance later. The camera is on full manual mode, so I can control the aperture and shutter speed. The ISO is kept low (100-200) to keep noise down.
I use a tripod for the camera and a light stand for the external flash unit (strobe). I generally use only one strobe for lighting a small painting and two strobes if it’s a large painting. The strobes are triggered with cheap wireless flash triggers. The flash is placed as far as possible from the painting to ensure even illumination. The angle to the painting is around 30-40°. By keeping the light source angle so small the brush strokes can be seen better because side lighting reveals texture.
1. Tilted camera approach
Normally when photographing artwork, it’s advised to keep the camera centered and parallel to the painting. In this setup, however, the painting is shot from a higher angle, so the camera sees less reflections of the canvas texture and brush strokes. The lens aperture is kept small, around f11 in order to keep the whole painting in focus. See image below.
After the image is taken, there’s going to be vertical perspective distortion. The farther the camera is from the painting, the less perspective distortion there is to correct. I take care of the distortion with Photoshop Elements’ vertical perspective correction tool. Now the image is rectangular, but too short vertically. That’s corrected with selecting the area of the painting and stretching it vertically using Free transform tool until the correct aspect ratio is reached. All this pixel stretching degrades image quality, but it’s not an issue though when posting small images to a blog.
I would much rather use a tilt-shift lens (e.g. Canon TS-E 90mm), but those are pricey. It would allow keeping the camera parallel but off-axis to the painting and no perspective tweaking in post would be necessary.
Tilted camera setup
- Most reflections are gone
- Colors look natural.
- Not possible to remove all reflections.
- The need to correct perspective and aspect ratio in Photoshop. Image quality drops.
2. Cross polarization
In cross polarization the light from the strobe is polarized by placing a piece of linear polarizing sheet in front of it. A circular polarizer is placed in front of the camera lens. By rotating that filter it is possible to control the amount of direct reflections. I prefer partial polarizing, since the texture looks more natural. I keep the lens aperture around f5.6, which is small enough to get a sharp image but large enough for the flash to be able to produce enough light through the polarizers, which eat light quite much.
Cross polarization setup
- The amount of reflections can be controlled and completely removed if desired.
- The colors are too saturated and contrast is increased: the dark areas go easily too dark or black, especially if the painting surface is matte.
- There’s a lot of tweaking in Photoshop when trying to match the colors to the painting.