scratchboard

[ skrach-bawrd, -bohrd ]
/ ˈskrætʃˌbɔrd, -ˌboʊrd /

noun

a cardboard coated with impermeable white clay and covered by a layer of ink that is scratched or scraped in patterns revealing the white surface below.
Also called scratch·card, scraperboard.

Origin of scratchboard

First recorded in 1925–30; scratch + board