It's funny how two people looking at the same colour will never see that particular colour exactly the same.
Two peeps looking at a blue couch for example, due to the differences in the processing of signals by our individual brains, will see the same blue couch in an ever so slightly different shade.
Unless your colour blind. Then it'll be brown or something.
But we're all in sync, 'cuz we're taught what colour is what from a young age.
.....Rainbows are lovely.....