Diffused Light for Coin Photos

Contrasty or Soft Lighting

After lighting direction, the size of a light has the most to do with how an object will look. By "size" I don't mean the power of the light, but rather the physical area of the light source, in relation to the object.

A tiny, point source of light will create bright highlights and deep, dark shadows. This increases the sense of sharpness in a photo, but it can also obscure important factors such as toning or luster on a coin.

A broad light source will reduce the harshness of highliights and soften shadows. While some sense of sharpness is lost, the increased visibility of other details can make this a good tradeoff. Carried to an extreme, however, a very broad light source can make a coin look flat and lifeless.

The distance of the light source mattters, too. Although the sun is a very large object, at its distance from earth it occupies less than 1/2 of a degree in the sky, so it acts like a point source, producing very contrasty light. On the other hand, a small household light bulb placed a couple of inches from a coin can act like a very broad light source.

Choosing between contrasty and soft lighting for coin photography is a subjective matter, but it is easy to get the degree of contrast you want by changing the size of your light source.

Creating Softer Light wth a Diffuser

The easiest way to make a light source larger and softer is with a light diffuser. This can be any form of translucent material placed between the light and the subject. The diffuser then becomes the light source, which is now as broad as the lighted area of the diffuser.

Professional photographers use many fancy types of light diffusers such as scrims and soft boxes, but at the scale of coin photography you don't need anything that elaborate. For instance, you could use something as simple as a sheet of plastic from an overhead fluorescent light, as in the setup below.



I propped this plastic sheet against my camera, but you could also mount one directly in front of a light with a simple clamp (being careful of overheating, of course).

This sheet of plastic has now turned my small light source into one that is a full foot square. The result is a photo such as below...



To my eye, this is an improvement over the bare-bulb photo I showed in my last post, but it still isn't good enough. The single light source still gives uneven lighting across the face of the coin and the angle of the light leaves the shadowed areas a bit dark. In my next post I will add a second light in the form of a reflector to correct these problems.