I would like to describe the surface of an object (concretely a ball) in a scientific paper. At the moment my wording looks like this:
(...) especially since the last change of the rules which leaves 50% of the ball's surface open to any color or patterns.
Is this wording correct? Basically I want to describe that the rules for some section of scientific work have changed. Formerly objects surfaces were colored with a single color, now there are specific rules for the coloring. In this sentence I would like to describe the changes for balls: now 50% of their surface has to be white, the rest is open to any colors/scenes/patterns.
How would one word this in the correct way for a scientific paper?