Rosco, in conjunction with Strobist.com, have created a purpose-built pack of gels, designed specifically for flashgun use...
Rosco – The Strobist Collection
Strobist photographers are a resourceful bunch, and once they figured out that a pack of colour samples for Rosco’s lighting gels were the perfect size for gelling flashguns, requests for the free samples went through the roof.
Now Rosco, in conjunction with Strobist.com founder David Hobby, have created a purpose-built pack of gels, designed specifically for flashgun use that, although no longer free, is still a snip at just £8 and are still selling out faster than most stores can stock them. The pack includes 20 colours of Rosco Cingel filters – a range that has won two Academy Awards – with multiple pieces of each colour to make up a pack total of 44 filters.
By using these gels over your flashgun you are able to shift the white balance to create interesting colour effects, and by matching your camera’s white balance to the filter colour, you can keep your subject in regular colour balance while the background colour changes.
The filters work really well and are a quick and easy way to create effects. Currently the best way to attach them, though, is with a little Blu Tack at each side - though there is a rumour of a dedicated holder coming soon. At this price, they're a must for any fan of flash photography.