Author: Robert W. Boyer
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I’ve got a brand new X-Rite Color Checker Passport. The new version has acquired some additional features such as the ability to generate ICC camera profiles for Capture One, in addition to ACR camera profiles. It’s also got some nice features for highlight, midtown, and shadow calibration using scopes in video editors. Those things are great and certainly worthwhile, but new features were not the real question I wanted answered when asking myself about when it might be time to get a new color checker. Instead I was more curious as to how far “off” an old color checker might be due entirely to its age.
It just so happens that I have a color checker passport that’s about a decade old. Through pure luck it’s also in pristine condition. For most of its life that particular color checker has seen almost no use. It has only seen use a handful of times and it’s never been left open lying around. I happen to have quite a few color charts and this particular one happened to be a sort of backup that languished in the pocket of a travel camera bag. If your color checker sees a lot more use, dirty environments, is exposed a lot more than mine has been, or is touched a lot, it’s probably going to show very different results than this little experiment.
The Setup
I don’t find myself making pictures in a lab — ever - so this particular test is simple, strait forward, with reasonable precautions to make sure the results aren’t completely compromised with a lot of variables such as a light source that’s really warm, super cool, or extremely narrow in it’s color. Those things can be tricky and may exaggerate tiny things that have nothing to do with any difference in color of the color checker. I’ve also made sure there are no extreme reflected colors from the environment or other light sources that could be localized in the frame.
Details:
- Light source was a Profoto A1 strobe bounced off a neutral reflector.
- Both color checker passports are in the same frame relatively close together.
- The rest of the scene is composed of neutral colors, specifically black and white prints on a variety of Moab papers without optical brighteners.
- I made multiple exposures and verified the results across them.
- I made two versions of each test in Capture One with *no adjustments other than sampling the white balance on corresponding neutral patches of each color checker passport.
- I sampled various ares of each neutral patch and used neutral all of the available neutral patches on each color checker averaging the results.
- The new color checker passport is on the right. The old one is on the left.
I used a neutral subject in most of the frame because it’s easier to see color differences in neutrals than it is on more saturated subject matter. Take a look for yourself. You probably see that there are two distinctly different color balances between the two versions in the ”whites” but it’s hard to tell if you are looking specifically at that color patch on each passport.
The Results
Taking a look at the larger targets first, the average sampled white balance for the old passport was a temperature of 6865 and a tint of 1.3. The new color checker passport produced an average temperature of 7036 and a tint of 1.6. What do these results mean? It means that the old passport is measuring the light as 170 degrees cooler and 0.3 points more magenta than the new color checker. These difference show that the old passport has a neutral patch that is a bit warmer than the new one.