You can know if your dog can see in color by showing them a series of colored images depicting movement such as a red running cat against a green background in a way that is not detectable unless the colors of red and green can be distinguished.
The color red appears dark brownish-gray or black to a dog.
And yellow, orange, and green all look a bit yellowish to a dog.
Dogs see the colors of blue and yellow but not the other colors.
Dogs only have 2 types of cones and can only discern the yellow and blue colors and is a limited color of perception called dichromatic vision.
Human eyes have 3 types of cones which can identify a combination of red, green and blue.
Dogs can see color although dogs can only see and discern the colors of yellow and blue as dogs only have two types of cones while humans have 3 types of cones that allow humans to identify combination of red, blue and green colors.
So dogs cannot see all colors that humans can but dogs do see some colors.
Dogs have what is called dichromatic vision.
Dogs can see in the dark as they have rod-dominated retinas that allow them to see well in the dark.
Although because their retinas' contain only about one-tenth the concentration of cones (that humans have), dogs do not see colors as humans do.
Dogs stare at you as a way to show affection to you and also because they may want to play with you or be petted.