Detailed mechanisms of human vision should be clarified against the background of the preparation of printed outputs for recognition via human vision. Our approach is to study visual illusions, which often uncover interesting aspects of visual mechanisms. The Herman Grid type illusion is studied to clarify the edge enhancement effect of human vision system; this type of illusion is considered to be associated with lateral vision inhibition. We quantitatively measure the effects of the Herman Grid Illusion. Measurements were carried out using a black and white pattern, as well as three primary color patterns to confirm the color dependency of human vision. The results of these quantitative measurements are expected to help to identify ideal imaging systems from the viewpoint of image recognition mechanisms.