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Gray Calibration of Digital Cameras to Meet NIST Mugshot Best Practice



M Rubinfeld, Charles L. Wilson


A primary objective of any process of photography, electronic publishing, or printing is to reproduce all colors as perfectly as possible. A good starting point is to render a series of known shades of gray as accurately as possible. The goal of this experiment is to show how digital camera images can be calibrated to meet the NIST Best Practice Recommendation for the Capture of Mugshots1 (BPR) Document. This paper represents the results of a two-part experiment that was conducted to determine the best methodology for calibrating digital cameras for rendering gray images as close to the eighteen percent gray intensity level, specified for background color in the BPR document. The first part of the experiment was conducted to determine the characteristics of specific cameras used in the experiment by measuring the rendered version of various known gray intensity levels and determining the amount of non-linearity among the quantified gray samples. The second part of the experiment was a measurement of the effect that different colored clothing had on the rendered gray background for each digital camera used in the experiment. Results for three specific digital cameras are presented to illustrate the methods involved. These results will soon be out of date because the technology is changing very rapidly.
- 6322
Report Number


digital camera, experiment, gray calibration


Rubinfeld, M. and Wilson, C. (1999), Gray Calibration of Digital Cameras to Meet NIST Mugshot Best Practice, - 6322, National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed April 16, 2024)
Created June 1, 1999, Updated March 5, 2009