Strobist recently did a post on How to Photograph Water Drops with One Speedlight, with some great info, including a few videos.
It's something I've been intending to do for a while, so yesterday I pulled out my camera, tripod, flash and remote flash trigger, and gave it a try.

First I tried using water, dropping into a dish of water. I experimented with different coloured reflectors behind the water, with varying results.

water coronet

Canon EOS 50D, 100mm f/2.8 macro

water tower

Canon EOS 50D, 100mm f/2.8 macro

Then I tried some red food colouring in dripping source, and blue food colouring in the dish underneath, and had some interesting results.

red water dropping into blue water

Canon EOS 50D, 100mm f/2.8 macro

I then replaced the water in the dish with milk, and dropped red-coloured water into it. The milk provides quite different results, as it eliminates most of the reflections and refractions, and results in a "cleaner" look.

red water dropping into milk

Canon EOS 50D, 100mm f/2.8 macro

milk coronet

Canon EOS 50D, 100mm f/2.8 macro

It was a lot of fun, and I was quite happy with the results. I'll definitely be trying this again sometime in the future.

Some things I learnt from this session:

• Doublecheck your camera settings (I didn't realise my camera was on ISO800 until afterwards).
• Use clean water.
• Ensure all surface bubbles on the water are removed.
• Make sure any logos at the bottom of the dish catching the drops are not visible.
• Ensure food colouring is mixed evenly, otherwise you'll see streaks in the water.
• I need a better way of controlling the rate of water drops.
• It's harder to get photos of the coronets (crowns) than I realised.
• You can fill up a compact flash card very quickly with this sort of photography!
• Coloured water provides better results than clear water.
• Coloured milk provides even better results again.