Dogs may not see as many colors as us but no they are NOT color blind.
This means that they can see more colors than just black or white or the grey. Earlier vets used think that dogs were color blind but the recent studies on Dogs cone photo receptor cells indicate they can perceive colors.
It is the cone photo receptor cells that enables any species to see the colors. Dogs only possess 20 % of CONE receptor cells as compared to humans. Thus they can see the colors but not to the extent as we humans do.
While dogs can see yellows, blues, and violets, they can’t perceive the reds, greens, and oranges on the color spectrum.
Hence don’t think your dog is stubborn when he passed by your red toy that you have just thrown over the green grass as he may not have distinguished the same though he will most probably find the same due to superior motion detection ability.
While they can’t see the colors as vividly as we humans can, dogs have the ability to see in night. This is because they have less cone cells but more ROD cells as compared to humans. Rod cells are the one responsible for sensing the lights. They also have tapetum, a layer of tissue just behind the retina. So they are able to see even in dim lights.
Tapetum is the reason why the dogs eyes glow in the dark.