The white balance setting on digital cameras is one of the coolest features. Back in the dark ages when we still used film there were two types of color film available: daylight balanced and tungsten balanced.
Almost all the film available at the stores was daylight balanced. Most people used daylight balanced film for everything, so the tungsten film didn’t sell well. In general daylight film worked well but existing light photos in an office building under florescent lights came out green and at home under incandescent lights the photos looked orange. In those times to fix this you had to put a blue filter over the lens to compensate for the orange incandescent or a magenta filter for the green florescent ones.
White Balance and mixed lighting
The Auto White Balance setting in the camera handles most of these lighting situations well without any effort or thought. So end of story right?
Yes and no.
If all of the light in a room is of the same kind and fairly standard (sun, flash, florescent, incandescent) then auto White Balance should work fine. If all of the light is of one kind but a bit out of the ordinary (sodium vapor, CFL) then doing a custom White Balance is an amazingly useful tool.
Digital camera flash and mixed lighting
However, the problem comes in when there are more than one kind/color of lights such as when using a flash indoors. Using flash indoors introduces some white light into an area that already has some color of light.
Subjects near the camera tend to look okay but everything else comes out orange or green. This happens because flash is near the same color as daylight, in photos it usually looks white/blue, incandescent lights tend to come out orange, florescent lights look green. The chip in the camera simply cannot adjust for all of the colors at the same time.
Flash in an Incandescent/Tungsten lit room
If we set the White Balance for Daylight, or Flash that is more or less the same setting, then the lights in the ceiling will appear orange.
If we go the other way and set White Balance for Incandescent lighting, the flash looks blue and the ceiling lights will appear correct.
How to fix this?
If you are shooting with just the existing light see if you can do with just one lighting source. In other words, eliminate one of the two sources. Turn off over head lights or close the blinds/curtains. Shoot slow exposures using a tripod.
For this article I am assuming you want to use flash.
When photographing Real estate or Indoor Portraits, I try to turn off the lights I don’t like. I’ll light most of the space with flashes and/or daylight if possible. For events this doesn’t work well since you can’t simply walk into a party and start turning off lights and drawing the curtains. So the solution is to change the light coming out of the camera to match the existing lights.
Gels are small pieces of colored plastic made just for mixed lighting and are used for light correction lighting effects. They come in various strengths and colors and are available from most photo retailers.
The best Gels are made by Rosco or Lee. My favorite is the “Strobist Collection” by Rosco. This is a pre-cut assortment of the most useful colors and come with a holder to attach them to a flash. For each kind of light you need a corresponding color of gel.
In our indoor example, an orange gel (called CTO for Color Temperature Orange) was used on the flash to change the flash output to the same orange light incandescent lights emit.
Now that all the light is orange. we set the White Balance to Tungsten and the camera interprets it correctly. The photo will look like everything was lit with white light.
If the light in the room is florescent, I would Gel the flash green (called FLD) and set White Balance for Florescent.
In a perfect world you might only need these two gels. However there are many different colors of florescent lights and other indoor lights such as compact florescent lights (CFLs). When in doubt about the type of light, take a non-flash photo in the room with the camera set to daylight White Balance. If the photo looks green, gel the flash green; if the photo looks orange, gel the flash orange; if it comes out pink, gel the flash pink and do a custom balance.
Some tips for using photo gels
- You don’t need a gel holder. You can use Velcro, or masking or gaffers tape. Gaffers tape is like duct tape but without the sticky residue and is the best choice. In fact opaque tape can be used to seal the edges so no white light escapes around the gel.
- More power: It may seem counter intuitive but increasing the flash power actually makes the color lighter. Lower power equals richer color.
- Heat: True Gels are heat resistant. Other colored plastics may work but could also melt onto your flash.
- Built-in flash: If you are using a built-in or pop-up flash all of this information still applies. Simply cut the gel smaller.
- Stack them up: Gels, even of the same color, come in different strengths. They are usually expressed in fraction: full CTO, half CTO and so on. Stacking a full CTO and a half CTO does give you one and a half CTO. In this case, it would provide a very warm orange light that would go well with candle or fire light.
Experiment with gels
Using gels opens up a world of effects based on the color of the flash. Here are few ways to experiment with gels. Also get creative and use your own combination.
- Try geling the flash blue and shooting outside in daylight. Shoot RAW and, when processing an image, set the white balance to match the flash. This will shift the normal sun light much warmer to look kind of like sunset. But the person will look normal.
- When Halloween rolls around again try gelling the flash some weird spooky green or purple. Try more than one flash and go for many colors and angles.
- If you have more than one flash, lighting the background a different color than the foreground is a good way to get separation and maybe even some emotion.