backing board, <of a sign>
backboard, <of a sign>
surround or extension to a sign used
- to improve conspicuity of a sign by increasing its size and isolating it from its background;
- to improve conspicuity of a sign by virtue of the colour of the backing board;
- to reduce the effects of glare when the Sun is low and behind the sign
Note 1 to entry: This entry was numbered 17-69 in CIE S 017:2011.