Note: This post was migrated from my old blog software. It hasn't been cleaned up yet (and might not ever be). Don't be surprised if the formatting, links, images, etc... are messed up.
The first time I tried setting up an infrared flash to do flash
photography without visible light was back in the film days. The
experiment didn't last long due to the price of materials. To
filter the flash, I saved up and bought a 3x3 Kodak 87C infrared
filter. These things aren't cheep. I think they were like $45-50
back then. Now they go for about $57. One thing to keep in mind
with a filter that blocks all the visible light and only lets
infrared pass is that the visible energy turns into heat.
The first time I popped the strobe after taping the flash to the
front I had it at full power and the filter singed, hissed and
crumpled up a fair amount. If you have ever seen a piece of surran
wrap get to hot and crinkle up it's the same thing. This was when I
was in high school or early college. And while $50 is nothing to
sneeze at today, it was way more of my income back then.
This time I'm going to try the trick of using an unexposed but
developed piece of slide film for the filter. Originally, I was
thinking about doing this with my Alien Bees which would have
probably required getting 4x5 film, but since I've been reading a
lot of strobist, I'm going to be
running this with smaller strobes which will allow me to run with
120 film. If this works, it'll be waaaayyy less expensive per
filter, and I won't mind as much if they burn themselves up.