After spending quite a lot of time recently playing around with soap bubbles and getting mesmerised by the swirling colours and patterns that form on their surface I decided to get a little bit more challenging and try to work out a way of photographing the bubbles as they burst. All my previous “bursting bubble” photos up to today were just lucky flukes where the bubble just happened to burst as the picture was taken. So, how to make the things burst on demand? Bubbles are surprisingly resilient – for example water drops pass through them usually without bursting them, as does a pin.
That was the first problem. The second problem was how to take the exposure just as the bubble actually burst. High speed flash was the obvious answer, rather like photographing bursting water balloons. With bursting balloons we use a Pluto Trigger to listen for the sound of the balloon popping which then causes the flash to fire. I’d tried poking the bubbles with a pin before but it doesn’t work, the pin just passes through the skin without popping the bubble. In the past we’d also shot tomatoes (and other messy things) with a low powered air pistol and this once again seemed like the perfect solution. The noise of the air being discharged would be more than enough to set off the sound detector on the Pluto Trigger and the air alone, without any form of pellet, should be enough to burst the bubble.
Surprisingly it all worked rather well. In fact it was downright simple to set up and once I’d found the right distance and set up the timing delay (who would have known just how much difference a single millisecond makes!) it was quite easy to get fairly consistent results doing something that by it’s nature is fairly chaotic.
These were taken with the standard studio flashes which fire at 1/5000th of a second. As you can see 1/5000th is not fast enough to freeze the motion (back to those pesky little milliseconds again!) so next time I will probably use the Profoto D2’s which have a shorter flash duration. There is a bit of a Catch 22 going on here as to get the colour in the bubble you need a reasonable amount of overhead light, but the brighter the light the longer the flash duration. I can see another day coming up where I’ll be using the Profoto’s and juggling power to flash duration ratios to get the best results. I’m looking forward to it already!
All in all a fun couple of hours playing!