It is true that there are colours that we can’t see? If so why can’t we see them?

Question: It is true that there are colours that we can't see? If so why can't we see them?
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- Royal Society of Chemistry: Find out more on:
  
  human
  
  perception
  
  wave
Asked by to Rowena, Roy on 21 Mar 2014. This question was also asked by .
- Rowena Fletcher-Wood answered on 21 Mar 2014:
  
  Colours correspond to different wavelengths of light in the electromagnetic spectrum. Red has ling wavelengths and blue short wavelengths and green is in the middle. There are types of electromagnetic radiation with shorter or longer wavelengths than these but we don’t see more colours. Infrared has slightly bigger wavelengths than red light (then radio and microwaves are even bigger) and ultraviolet has shorter wavelengths than blue light, before stuff like gamma rays!
  
  We can pick up on these kinds of radiation other ways, but we don’t “see” them as colours.

Question: It is true that there are colours that we can't see? If so why can't we see them?