I am generating multispectral images using Raw (.NEF) photos with the colorchecker passport 91-3% standards. However, when I go back to measure the RGB values for a mean reflectance in my multispec image, the mean is always way too low (i.e. the (91% reads as 89%, the 59% reads as 56%, etc.). Any thoughts as to what may be causing this error?

Standard Values too low when Measured
Cedric van den Berg Changed status to publish October 19, 2021