[Carboniac]

Id be really curious to see what happens if you make up a target with a black center the size of the yellow and everything else white.

 

[Carboniac]

It might be something specific to yellow. Yellow isnt a normal color - what you see is a virtual. color.

Personally I see the difference between yellow and red but its hard for me to to focus on the boundary. If it was yellow bordered by blue it would be much easier for my eyes.