A technical question: How did he drown out the pink? Did he just ink over the words in black? Would he have to hit all the same exact ink...holes to do it? Or is it just not that hard and I'm over thinking it?
Black is good cover-all for unwanted color. I don't think it requires any greater precision than a standard fill -- magnum needle arrays can cover areas evenly enough that a light color like pink wouldn't stand a chance.