One of the things I hear that people really struggle with is how to use gels to make colored backgrounds. Why would we want to do this? Well, because sometimes a basic single color background is just boring. Adding some gels to the a background light can make it much more dramatic or even set a particular mood or theme. Adding colored gels to your background light can give you a virtually unlimited number of backgrounds.
What you will need
To start off with, you should get a set of gels. The set I recommend is the Strobist Gell Collection since it contains a large number of gels of different colors that are pre-cut to fit most speedlites. Second, you will need some way to attach the gels to your speedlite. I generally use the Lumiquest Gel Holder or just some basic gaffers tape.
Once you have the gel attached to your flash, you are ready to get going.
The Lighting Setup
This is where people often get hung up because a poor setup can cause light to spill on to the subject or the main lights can wash out the color effect. Ideally you want 3 feet or more between the background and the subject to prevent spill and you want the main lights to be angled enough to not spill onto the background to wash it out. Later on we will look at some actual setups to show how they are done.
In the first image, we saw just a plain black background which was done with black seamless paper and the lighting was coming from an side angle to prevent hitting the background. In this image we have a single speedlite one 1/2 power with a purple gel shooting up from behind the subject. This is a very simple yet effective setup since it used a single light source. To help the light spread out, the flash zoom was set to 24mm to make it as wide as possible (without a modifier).
If the flash isn’t set high enough you won’t get much of an effect. If it is set too high, the color will wash out and you will get white.
If you want to take it a step further add a second light with the same or a different color. In this case I changed the purple to a red and added a second flash with a blue gel. Take notice that where the colors overlap they actually mix and become purple. If you are trying to use two different colors, you will need to keep this mixing effect in mind and might have to take steps to flag the two flashes to keep the colors from mixing.
Another thing to try is to use multiple gels on a single flash by covering half of the flash with one color and the other half with a different color. For a recent benefit shoot I tried this with pretty decent results.
Again you can see the distinct blue and red colors but a purple where the colors mixed. I am going to continue to play with this technique and see what I can get with possibly using a vertical card in between the two gels to try to keep the colors separated more.
Even though the colors mixed more than I would have liked, the overall effect was very nice although I later wished I had used a white or black background as the gray seamless was a little too drab where the color wasn’t hitting it.
The following is an image from the shoot showing how the images turned out.
What I really wanted to achieve was a red, white, and blue effect so back in the studio I start experimenting to see what I could come up with. What I finally came up with was a three light setup with bare flashes with the gels on the bottom and an non-gelled flash higher up to provide a white splash. If I used just a bare flash for the white, the spot was too big and washed out the other colors so I added aÂ Rouge 3-In-1 Grid to keep the light contained.
The first test was alright but the white spot was too small.
Hopefully this will inspire you to get creative with using gels for different background effects. It just takes a little patience and practice to get it all dialed in right, but once you do, the possibilities are endless.