If you want to play ball searching games while out and about, choosing a red ball might be the best for hiding from your dog. But if fetch is your game, blue might be better!
2017 research (Siniscalchi et al 2017) shows that dogs likely have dichromatic vision, similar to that of a person who is red-green colour blind. Indeed, this research devised a test for dogs like that which is used to assess human colour vision.
On top of previous works that have shown that the dog’s eye structure allows for colour vision, given the abundance of cones within retinal structure (Neitz et al, 1989), we can put the myth to bed that dogs see in black and white only.
All of this means that your dog’s toy colour matters!
If you want to play fetch out and about, blue is a better toy colour than red. Red, against green grass and vegetation will appear, to your dog, as about the same shade of grey-ish, making it hard to spot.
But, if you want to play toy search games, red might just be the best colour, causing your dog to have to really use their nose, rather than just immediately seeing the toy.
Decker has difficulty locating the red ball in all that greenery, until he engages his nose!