how do we see colour and not dogs

Question: how do we see colour and not dogs
- Keywords:
  colour,
  dog
Asked by dudets to Lydia on 19 Nov 2014.
- Lydia Bach answered on 19 Nov 2014:
  
  Heya!
  
  Dogs only see colour in a similar way to people with red-green colour blindness, they are also less sensitive to variations in grey shades and only about half as sensitive to changes in brightness.
  All mammals we can see using photoreceptors in our eyes. These cells, which look like cones, transmit signals about colour of light that they are hit with to the brain. Us humans have three different types of cones in our eyes which allow us to distinguish red wavelengths from green and blue wavelengths from yellow, while dogs have only two types of photoreceptor cones.

Question: how do we see colour and not dogs