Why does this question matter?
It may be thought that it really doesn't matter whether dogs see in full colour vision or not, but actually it has practical consequences that we perhaps hadn't thought of.... For instance, if your pet can't see certain colours very well, it is far better to have their toys coloured so that they are both visually appealing and can be seen!
The History of Dog Vision...
The senses evolved to meet certain purposes necessary for survival. Dogs were primarily nocturnal hunters, so night vision and motion detection would be far more important to their survival than colour vision. In fact dogs are far more sensitive to motion at far greater distances than us. They needed better night vision, but for the purposes of hunting an eye for detail was not required. Their peripheral is also far better than our own, partly because of the placement of their eyes located either side of their nose meaning that they can scan far larger areas for prey without needing to turn their heads.
So What Can Dogs See?
Dogs do not only see in black and white but their colour spectrums are far reduced compared to ours. Dogs have similar vision to a red-green colour blind person. Do you ever wonder why your dog loves a tennis ball, but fails to retrieve their red kong ball when you throw it for them to fetch? Well they may not be able to see it very well! The crazy thing is that dog toys are frequently made in colours that dogs cannot see well; they are made to be visually appealing to owners as opposed to their dogs after all dogs cannot purchase toys for themselves!
Dogs can see yellows and blues, perhaps next time your pet is due a new toy you could check to see if you can find one in these more visually appealing colours!