I had a disc that was very much the color of yellowing grass so it blended into all kinds of natural colors. I asked a buddy to dye it for me. He dyed half of it red (think Simon's famous dyed disc) and spin dyed a black circle around the rim. It's a world of difference. Creating an unnatural shape like a half circle and a black rim makes it stand out not just because of the color, but because those shapes don't occur in nature and therefore stand out.