Environmental Stability Analysis

Essential Information for Photographers and Filmmakers

“The ColorChecker Color Rendition Chart (often referred to by its original name, the Macbeth ColorChecker[1] or simply Macbeth chart[2]) is a color calibration target consisting of a cardboard-framed arrangement of 24 squares of painted samples. The ColorChecker was introduced in a 1976 paper by McCamy, Marcus, and Davidson in the Journal of Applied Photographic Engineering.[3] The chart’s color patches have spectral reflectances intended to mimic those of natural objects such as human skin, foliage, and flowers, to have consistent color appearance under a variety of lighting conditions, especially as detected by typical color photographic film, and to be stable over time.”

The venerable Macbeth ColorChecker chart has shown an amazing resurgence in use and popularity in the digital photography era, proving especially popular in digital camera profiling applications and for many print quality control tests as well. Because the chart’s visual appearance is so well known in the photographic community Aardenburg Imaging repurposed its 24 assigned colorimetric values as the core group of color patches in our standard 30 patch color target we use to test lightfastness of modern inks and media. These color values do a great job exercising critical color blend transitions in muliticolor channel inkjet printers while economizing on the number of patches needed to properly evaluate an ink set’s overall light fade characteristics.

Funding for the project is currently allocated through the Aardenburg General Fund.

In order to serve as a camera calibration standard each Macbeth Color chart is manufactured to very tight colorimetric tolerances, and the color patch values need to maintain their exacting spectral properties as long as the target is in service. The Macbeth target’s manufacturer, Xrite.com, advises that each ColorChart should be replaced every two years to ensure the color accuracy of the patches. However, the targets are relatively expensive, and many photographers retain and use their Macbeth targets for many years. Given Xrite’s conservative recommendation to replace a target after only two years in service, it begs the question “Should photographers be carefully heeding this advice?”

The goal of this project is two-fold. First, it is intended to test the stability of the chart colors over time and to learn how the targets actually age over time. Is light fading an issue, or are other environmental factors like heat and/or humidity a more significant factor? Or, is physical wear and tear during use the primary concern? For photographers and printmakers who own a spectrophotometer, tracking the color accuracy of the target over time may well be an easy way to determine when the target should be replaced, but many photographers don’t have ready access to this equipment. Further guidance on the care and handling needed to extend the service life of the target seems warranted. This is the first goal of the project. The second goal of the project is to publish additional advice on how to use the target to evaluate factors such as a camera’s exposure latitude (i.e, when does unrecoverable color clipping occur in the camera’s RAW file highlights and shadows), and how to track and identify color calibration errors during printing (.e.g, is the printer, monitor, or digital file to blame for unwanted errors in the final print?).

The work product will be lightfastness test results, and two-year real world environmental monitoring results for a minimum sample size of six randomly purchased targets. The projected is expected to cost $6,000, the costs largely attributable to the labor required to measure and monitor the samples over time, and the time needed to produce the final report. Please help us fund this uniquely independent research on the product durability of the Macbeth Color Checker Chart.

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