Hi Matt
Here's a bronze example using the same set up:
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I should have added, the background can be important, worth experimenting. I bought some different coloured crafty materials from the local Tescos (sheets of non-relective foam-like material. Depending on the tone of the coin you are photograhing, lighter or darker backgrounds may work best.
The key to the bulb is that you get best results with daylight white - the local DID store should stock them, I got mine on-line. Often bulbs are 'warm white', giving a yellow hue, which in theory can be corrected using the white balance settings on the camera (if you have them), or post production, but I have had far better results with daylight white bulbs. Thanks to Stuart (Coinery on here) for that tip (he even sent me some!)