"Optical Illusion" feels strong here -- really the image is just being desaturated. Same effect can be seen by just replacing random pixels with their grayscale

"Optical Illusion" feels strong here -- really the image is just being desaturated. Same effect can be seen by just replacing random pixels with their grayscale equivalent. Something like: width, height, _ = bw_img.shape pixels = int(width * height * .5) xs = np.random.choice(width, pixels) ys = np.random.choice(height, pixels) bw_img[xs,ys,:] = img[xs, ys, :]