Monday, April 03, 2006

Copying art - Lighting

No, I don't mean I copy artist compositions in my photography (although that's not a bad idea). I'm talking about flat copying - transferring an image of a painting to film or digital.

You'd think that would be easy right? Wrong. It's not easy if you want to do it properly. I recently demonstrated to myself how not to do it although the results were pretty good (coming through, mind my head) and perfectly acceptable to the customer concerned as it was for publishing on a website. However if the customer were a wallpaper manufacturer or a repo printer who was creating prints of fine art the results have to be, without question, spot on.

What do you worry about when copying a painting?

1. Lighting
2. Colour
3. Size
4. Focusing

I'll deal with one item here and move on to the other in later posts. I don't have time to do it all here and now. Actually this subject could be the subject of a book in it's own right. In fact I bet it is a subject of several books.

So to lighting:

You must control the lighting. Daylight is fine but hard to control so I'd recommend calibrated artificial lighting. If you have studio lighting then fine - that's the easy option. I don't have a studio (I'm too tight) so I used a pair of flash units. These should be placed at 30 to 45 degrees either side of the camera.

Ideally the flash units should be the same model and age. However that is not often possible for the casual photographer so you can get by with a mismatched pair but you must be careful to match their power. Check their guide numbers and adjust their settings to get as near the same output as possible. Fine tuning can be handled by moving a flash further away from or closer to the subject.

With the flash in place with appropriate triggers take a shot of a piece of white paper with something in front of the paper to cast a shadow. A finger of your (or an able assistant) is ideal. The image taken will have two shadows, one for each flash unit. Adjust the flash to subject distance to dilute or increase the light of one flash unit until the density of the shadows match.

At this point it is important to get the correct exposure. This can be done either by a process of bracketing the exposure or by using a flash meter.

From here you move on to colour balancing. That will be in the next thrilling installment. Watch this space.