There seems to be a general belief that when people think of how a dog sees the world is in grey scale. You always hear people say “dogs are colourblind” and that dogs can’t see rainbows.
Compared to humans, dogs do not see colours very well at all, this is however offset by other advantages that dogs have in their vision.
Although dogs are able to pick up a little colour, the red-green spectrum is predominantly going to appear browny beigy.
So, when you really think about it, Jake shouldn’t have been able to tell that Finn’s ruby was actually an emerald.
Here, have a link BLAM!