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Counteracting the Effects of Lighting On Digital Color Images: How to Standardize Studio Color Balance


Gary Box


Gary Box


Gary Box


Gary Box



One of the biggest frustrations we face as photographers is how to get perfect color, hassle-free. Much has changed since the days when you dropped off your film at the lab and the images came back with perfect color no matter what you had done.

Now that many of us are doing our own retouching and color control, we're discovering just how much the lab used to do. It's not so easy to get perfect color. Or is it?

HERE'S HOW...

1. The first step to getting consistent color is to work with a consistent color of light source. If you test and set your camera for that color, the color should come out of the camera perfect.

Let's say you have three different soft boxes from three different manufacturers. They all put out different colors of light, so stay with one brand of soft box, preferably one that will cause the least discoloration and won't yellow with age.

I tested four major brands of soft boxes to see which had the whitest light output. I color balanced for the bare flash tube of our Photogenic Powerlights, then aimed the front panel of each soft box directly at the camera and fired. I checked the color values in Photoshop to see which had the most neutral output—the one with the RGB numbers closest together.

In the test (third image down on the right), the light on the right, by Larson Enterprises, had the numbers 235, 235, 239—very close, with only a slight bit too much blue. The light to its left, made on one of my other soft boxes, produced the numbers 214, 206, and 196. Both soft boxes are about three years old, yet the Larson was still white, while the other had yellowed. It was like putting an amber gel over my flash.

I replaced all of my soft boxes with Larson. Now I have one kind of light and one color of light output.

2. After establishing a consistent light source color, it's time to test the lights and determine how to set my camera to match their output.

To do this, we photographed a known target that is spectrally neutral. We used a standard GretagMacbeth Color Checker (above, right), concentrating on the gray swatches. We use Canon cameras, which allow us to set an exact Kelvin temperature for our white balance. We photographed the GretagMacbeth chart with the camera set to 5000K, then at 5100K, 5200K, 5300K, up to 6000K.

With no other corrections or adjustments, we developed our RAW files, opened each in Photoshop, and measured the gray swatches with the eyedropper, looking for R, G, and B numbers as close together as possible. The 5500K gave us 176, 174, 173, so we set our studio camera permanently on 5500K.

Now every image that comes out of our flash camera room, using our standardized lights, comes out with perfect color. The only thing we do is boost our saturation through an enhanced camera profile.

3. This procedure worked perfectly until we bought our new Larson Fresnel light. Since the light goes through a plastic Fresnel lens instead of the normal soft box fabric, our first shot with it was off color, so we had to adjust for the Fresnel lens.

We did a test shot of our GretagMacbeth chart and clicked "balanced" on the mid-gray swatch then saved the setting in our Capture One raw software so every soft box shot is perfect.

Now we have a preset whenever we use the spotlight. Not all cameras allow you to adjust to a specific Kelvin temperature. For those models, just try each of the presets and see if one is close enough. If not, do what we did with the spotlight: run a test and save that setting and apply each time.

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