Raster™ Method for ADA Signs Using the Raster™ Method, you can create Braille text on an ADA sign by inserting a Raster™ bead into a hole. New Braille regulations make the Raster™ Method the preferred method for creating Raised Letter Signage. Traditional routed Braille signs no longer meet the latest 2008 accessibility guidelines, which now require dome-shaped Braille dots. It is essential that the dots are uniform in size and in the appropriate position in order for the reader to understand the correct meaning.