Calibration:
Determination Absorbed dose-pixel value
Remember that if using a 48 bits scanner :pixel value per color channel [0,65535]
Some film dosimetry softwares use calibration curves: absorbed dose-pixel value
Fit to a polynomic function or to a rational function (shape corresponding to the dose-
response characteristic of the film)
Fuß et al, PMB 52 (2007)
X(D) = a + b/(D-c)