Fluorescent light dimmer: it's that possible?

Hi everybody, got a friend that uses UV light tubes (aka wood lights) to make stunning light sculptures. He showed me a prototype wich should dim the UV lamp interactively, but I don't know where to start...

I saw around some dimmers based on phase controlled switching, will that work with fluorescent lamps?

Check www.alessandrolupi.com if you are curious!

There are dimmable ballists . . .

You'll have better luck with microcontroller-based dimmers than the simple R-C-Triac based ones like you find in the walls of most homes for starters. The current/voltage phase shift caused by non-linear loads like fluorescent lights can mess with the zero-crossing detection of the latter and cause problems (although adding a dummy load, like a few incandescent lamps, in parallel with the fluorescent fixture can help).

Best bet is a properly-wired dimmable ballast like BroHogan suggests, although FWIW I've been able to get some dimming range even with non-dimmable ballasts on ETC's Sensor+ family systems, but that might be a bit overkill for your application :). You will never get a smooth 0->100% dimming, though, even with the best ballasts and dimmers. Best case, you get something like off,40%->100%.