Colored gels can change the look of the light from shoe mount flash units and offer the photographer the opportunity for added creativity. Here's a review for the Rosco Strobist Collection.
Shoe mount flash units used creatively can do a lot for your photography. Besides adding light in interesting ways, they can provide a different look via colored gels that change the color of the light the flash produces. In the past, photographers have had to buy sheets of gels designed for studio lights and cut them down to fit a shoe mount flash.
Off-camera flash guru David Hobby at his great blog, used to tout Rosco gel sample packs that were ideal for use with shoe mount flash units. These small sample gels could be yanked out of the sample book and taped to the head of the flash unit. Since the company gave the sample packs away free (with just a small charge for shipping), a lot of photographers started requesting gel sample books. It finally hit a point where Rosco had to discontinue the service. Instead, the company has designed a small gel pack designed for the users of shoe mount flash units. (Check out this url for more on the history)
These small gels are perfect for use with shoe mount flash units either via gaffer's tape (or some other tape) or via a gel holder made by Lumiquest. The Rosco Strobist Collection Kit gel pack consists of 55 filter strips made up from 20 different colors of varying intensity. These filters range from color correction gels designed to warm or cool the light from your small strobe to neutral density filters to reduce light output to color filters for creative effects.
Using the Kit
Carrying a pack of these in your camera bag doesn't take up much space or add much weight. Get a tongue depressor and wrap some gaffer's tape or some other tape around it and put it in your bag with the gel kit and you're good to go.
Using a gel on your strobe can help you in several ways. First off, the right gel can help produce more natural looking light. The output from the typical shoe mount flash tends to be a little bluer than ideal. Using a CTO 1/4 gel ("Color Temperature Orange") to slightly warm the light from the flash. (David has an excellent post giving greater detail). Another use is to gel a flash on a white background to change the color of the background.
*Please note - the author received 'Rosco Strobist Collection Kit' from a company other than Bright Hub in order to develop the content contained within this article or review.