"Warren Weber" wrote in message
. ..



Hard, compressed board, usually dark brown with one very smooth side and
one
with a rough pattern, which is the "down" side...


Actually you can only tell tempered for sure by looking for an
identification red spot on the edge of the sheet. Tempered and non tempered
typically come with smooth on one or both sides and both may differ from
light to dark brown. Non tempered has a green spot on the edge.
It used to be that the red or green spot was sprayed on the edge of a stack
of hard board.