I'm writing the manuscript on an experiment using Gabor patches that were created based on the function and code shown in the images (from the Book 'Visual Psychophysics' by Zhong-Lin Lu & Barbara Dosher).

I set the value of 'c' in the formula to 0.3, and I'm wondering if this 'c' is the same as Michelson contrast (30%) or not.

If it is different, should I calculate the Michelson contrast by directly measuring the luminance values with a luminance gun and report that value in the paper?

Thank you in advance!