What comes after using an incident meter to set the exposure? Setting a neutral color balance then refining the exposure, both in post production. I always refine the exposure after neutralizing the color. Before going into the steps for either one, here’s some background on digital captures, especially RAW files. (You are shooting RAW aren’t you?)
RAW captures have a huge amount of information in them. Half of that info is in the brightest f/stop of exposure as shown in the graphic below. There are 8192 tones in that first stop compared to 256 tones in an entire JPEG. A 14bit RAW file has about sixty-three times more information to work with than a JPEG of the same subject. That extra data provides the headroom for creative enhancements in the RAW processor before ever generating pixels for editing in Photoshop.
RAW data is linear. There is no gamma curve imposed on the file as is the case in a JPEG capture. No curve means that colors won’t shift and contrast won’t increase either. Both happen to JPEGs when making big changes in exposure or color. The 2.2 gamma curve is necessary to distribute tonality so that it reads correctly to our eyes. Compare it to the linear version where the highlight data is expanded and the shadows are compressed.
Commercial photography for advertising, catalog and e-commerce sites must be color accurate. By that I mean the highlights, midtones and shadows want to be as close to neutral as possible. Neutrality in this case means no color cast. Colors are neutral when the white, gray and black swatches on an X-Rite ColorChecker® target, read the same values for the Red, Green & Blue channels. ColorChecker® targets are colorimetrically neutral. That’s one reason they are a bit pricy and priceless at the same time. If the patches are protected from fingerprints, and when not in use, kept in a dark envelope, they will last many years. Below, model Jennie Carroll is holding the ColorChecker® Passport. It’s a target in a durable plastic case. The file is open in Camera Raw 8.4.
The white patch (#1 sampler) reads R:243, G:244, B:240, the middle gray (#2 sampler) is: R:138, G:140, B:132 and the black (#3 sampler) shows: R:37, G:37, B:36. In each instance, the red and green are brighter than the blue. The color cast is slightly yellow.
After correction the numbers are much closer to neutral. #1 now is R:243, G:243, B:242, #2 now reads R:138, G:137, B:138 and #3 shows R:38, G:38, B:39. The White Balance tool was clicked on the patch immediately below the #1 sampler to neutralize the photograph. Their numbers, R:226, G:226, B:226; are the same and completely neutral. A one point difference on the other patches will be more than close enough for all but he most hyper critical color outputs. There are tools in Photoshop that can make the numbers match perfectly. The difference in the example is subtle and noticeable.
The corrected version is on the right. Camera Raw 8.4 is the first version that has before | after comparisons in the preview window. Press Q to cycle the preview modes. The “after” on the right shows three color samplers circled in red: #1 on the white patch, #2 on middle gray and #3 on the black patch. The corresponding readouts are shown in the red box at the upper left of the dialog. The next Exposure Tactics post shows how to tweak the exposure in post production.
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