On the weekend I got asked by a good friend if I could help digitising some large format artworks.
I knew the rough basics of reproduction photography, so I jumped right into it. Looking for a lighting that is as even as possible, the simplest setup is typically two light sources 45° to the left and right of the camera’s viewing axis. Of course, since you want the lighting to be homogenous, you’d want to use two identical light sources and a perfectly symmetric setup.
The camera itself should be positioned centred and completely parallel to the subject. Since what you are trying to photograph is typically flat, it doesn’t really matter what focal length you use. Hence, if possible, use your best lens at the focal length that it is best at. Close the aperture to the best trade-off between overall sharpness and edge-to-edge sharpness. If the aperture is too large (that’s usually below ƒ/4) you might get soft corners; if in turn it is too small (usually above ƒ/11), the overall image will suffer from diffraction softness.
Here’s an image of the setup that I used, which involved two flash units that I triggered wirelessly. Since the control / trigger flash produces light in itself (and thus ruins the evenness) I used a bit of aluminium foil to block it from shining directly onto the artwork.
PS: Yes, these are nappies supporting one of the flash units. I only have one bean bag ;-)