Today’s Question: If you are using Lightroom and you setup your camera for white balance by using a gray card, is it still necessary to use the ColorChecker Passport to setup a color profile the get accurate colors?
Tim’s Quick Answer: That depends on the degree of accuracy you require. For situations (such as product photography) where color accuracy can be critical, I would recommend building a profile based on the X-Rite ColorChecker Passport (http://timgrey.me/checkerpassport). For situations where the color accuracy in the original capture isn’t as critical, using a gray card is generally adequate.
More Detail: When using a gray card (or other color-neutral object) as the basis of a white balance adjustment either in the camera or in post-processing, you’re only applying a simple compensation to the color in the image that will produce a neutral value for that gray card. The X-Rite ColorChecker Passport includes a series of color swatches that can be used to apply a more accurate color adjustment to your photos.
In many cases, especially when you are exercising a degree of artistic interpretation for the colors in a photo, the accuracy provided by the ColorChecker Passport is generally not necessary. By using a gray card to compensate for the color of the light illuminating the scene you’ll be able to get a reasonably accurate result.
What you’ll find is that a gray card enables you to compensate rather effectively for the color of the light source. But the individual color values may still not be quite perfect. Because of the multiple color swatches on the ColorChecker Passport, individual colors will appear more accurate after applying the profile. This will produce a subtle (but sometimes important) shift in some of the individual colors within a photo.
It is worth pointing out, of course, that in some cases you don’t really need to use a gray card or other approach to compensate for the color of light. After all, using this type of approach is focused on removing the color element of the light illuminating the scene, and in many cases that color is a big part of the reason you captured the image in the first place.