Adjusting for RGB Values from Digital Photographs

[SPrice]

I am using ImageJ for a project in which I need to analyze digital photographs of animals for RGB values of specific areas. All photographs were taken in the same room using a tripod and controlled settings on the camera. Each animal photographed also had a true color chart placed beside it for reference. When I analyzed my pictures to test for proper color readings, something was not right. When I encircled the "pure red" value on my chart and clicked on "RGB Values" in the "Analyze" subsection, it gave me a value of 178.85, rather than 255.0. How do I fix this so that my analysis will be based off of the true color values?

[Peter van Loon]

Hi,

Have a look at:
http://imagejdocu.tudor.lu/doku.php?id=plugin:color:chart_white_balance:start

Be aware that the red color on the colorchart will not have a R value of 255. It will be approximately 175. So it is close to your measured value. See:
http://www.babelcolor.com/download/ColorChecker_RGB_and_spectra.xls

Regards,
Peter