Since I do most of my portrait shoots on location, I wanted a way to create different background colors with minimal gear and expense. I read a little about using gels to create colored backgrounds so I gave it a try today.
Anyone with any suggestions or tips is welcome to chime in.
I started with "thunder grey" seamless paper which is a very dark grey. Using a dark background allows blasting it with plenty of gelled light to overcome the spill from the main & fill lights. If you use a white or light grey background, it will just be blown out when you add any significant amount of light to it.
I mounted a 580EX II Speedlite behind the subject about waist high, four feet in front of the background, and aimed it at the gray seamless, angling it up to her head height.
I used gels from the Roscolux swatchbook that you can get for next to nothing. These swatchbooks have hundreds of gels to choose from. I picked the darkest gels in their respective colors to create the most saturated light possible. The gels nest under the tab for the wide panel on the 580EX II and will stay in place as long as they don't get bumped. Those with other brands of flash unit may need to find alternative mounting methods. Note: I would not recommend sandwiching the gel between the lens and the flip-down wide panel on the flash. The gels get quite hot and I would not want to risk damaging the flash from the heat buildup.
For today's shots I adjusted the power in order to meter the background more-or-less equal to my camera aperture. I was able to get into the f/9 - f/11 range with the 580EX II at 1/2 power.
Here's the Midnight Grey backdrop with no background light.
This is with the background light but no gel.
Gelled flash - #2002 "Storaro Orange"
#2005 "Storaro Cyan"
#39 "Skelton Exotic Sangria"