CUP & SAUCER

I was reading last night how the retina process the colors red & yellow and how, compared to green & blue, they will always look sharper.
Couldn't find what I was looking for at my mother-in-laws but found this sharp little color combo in the sink.

Funny. viewing this in preview, it looks pixelated even though it's not. anyone know why this might be or how to improve this?