Why are some salts colored even with all electrons paired?

[bsrishu]

why some salts are coloured although all the electrons are paired in it?
Ex: potassium dichromate, potassium permanganate, silver bromide/iodide.

 

[Borek]

You don't need unpaired electrons to have a colored salt.

 

[jd12345]

Its because of "charge transfer" that some salts inspite of having paired electrons have bright intense colour like KMnO4

 

[bsrishu]

can you please explain this charge transfer effect, and in which type of this will be observed?