Our image analysis procedure is based on the normalization of light reflectivity (𝑅) for two primary reasons: first, the normalized reflectivity expression (1 + Δ𝑅∕𝑅) accentuates minor variations, making it easier to detect local pits in comparison to raw optical images, where such subtle changes may otherwise go unnoticed. Secondly, it enables estimation of variations in surface film thickness on pit-free surfaces. This approach is grounded in the principle of light interference from interfaces and surface films akin to the ellipsometry technique. Normalization of images was conducted pixelwise by dividing the intensity of the reflected light (𝐼(𝑡)) at each pixel at time (𝑡) by the intensity at that same pixel at the onset of OCP exposure, 40 s prior to chronoamerometry, designated as: