I glue parchment paper over the entire face so I start with a clean white backer behind my targets...I don't need distractions in the scope,my mind likes to wander enough on it's own. I also glue(Elmer's white glue) my targets to the parchment,makes for nice clean holes...and peels right off so targets don't get damaged. Of course this is all done for my home range ,public range would not be ideal for this approach .The blue ones make the best target backers . Because of the contrast between target and backer of course.