Illusory colorization and display performance boost
The image for the post is a visual/artistic experiment playing with simultanous contrast resulting from other experiments these days. An over-saturated colored grid overlayed on a grayscale image causes the grayscale cells to be perceived as having color. This was originally done in the image posted on Facebook groups "2011-07-12-Railway People" by Chuwa (Francis), and I think to try to do this and get the same result.
Well, it was done:
You can see the original first attempt here: https://pippin.gimp.org/tmp/simultanous-contrast/sc-mid-saturation.png
What do you think?