Strictly put the title should read "How Dogs See". Here is my dog Tess (pictured in the background) EYING a box of milkbones. Almost normal dog behaviour....she really should be tearing the box up and making herself sick on the goodies. Tess, however digs experimentation. Here we have (only for the purposes of the challenge) created a sepia-ish box. It could be in full color (Tess knows that because in spite of her visual shortcomings, she can SMELL color.
OK, the reflected light rays converge on her iris and then the concave lens in her eye. Bingo, the image is inverted as it lands bent to the shape of her retina. But it is now in black and white....'cause that's the way we think dogs see....even milkbones, in BORING black and white. But, oh so foolish us! Tess is not bored, see her exceptionally intelligent face? Why? You may ask. Because she smells in COLOR.....what she sees is technicolor SQUARED, especially with milkbones. Look at that eye in the center (B and W for the challenge)it's wide open because of all those millions of little olfactory doodads in her schnozzle jazzing up that boring image. Which is why, folks, your mutt goes nuts over milkbones even when concealed in a plain brown(sepia)paper bag.