Not exactly sure how the whole things started, I was either at a doctors office or an insane asylum, either one would work. But I had a problem, I could not see the colors blue or brown, not all hues of blue and brown, but really specific wavelengths within the ranges of blues and browns.
The interesting thing about this is that if something was one of those colors it did not show up as grey, it was simply not there. Like you could use blue ink on a piece of paper and I would be completely unable to see it. I believe the sky would still be white, but then again I never got a chance to experiment in the dream to see if the sky would be stars, even in the daylight.
I think that the easiest way to describe it would be like in photoshop when you add transparency to a layer, it was like that. If because of some freak of nature the daytime sky was no longer blue and I could see the stars, even in the daylight that would be the coolest thing.