The light source I am using is known to have a Gaussian intensity distribution along the height. I took the raw images at "x" seconds of exposure. However, while taking the bright field image, the camera got saturated at "x" second exposure. So I ended up taking the bright field image at "y" seconds of exposure with $y<x$.
The conventional formula for flat field correction is
IC = [(IR - IB) * M] / (IF - IB) from ref
On using this I get,
Do I need to factor the exposure times during the flat field correction ? Thanks for the help