There have been a number of comments received raising the question: Why not just use White is Invisible? These are based on the erroneous assumption that this function must be the same as specifying White to create a transparent gif. In fact, White is Invisible is nothing like a transparent gif. According to a FAQ on the MC site, the White is Invisible option is designed to work with the primary shader, which in RDS happens to be red. You can get away with this in some simple applications on some colored primers but, more often, users are puzzled when they end up with an odd reddish hue in the areas of their paint shapes and maps when using this function.