THE AMBROTYPE - POSITIVELY NEGATIVE

HISTORY'S TIDBIT - Ambrotypes were an early form of photographic negative that appeared to the viewer as a positive image. A glass plate would be thinly coated with collodion, then dipped into a solution of silver nitrate. One side of the plate was subsequently coated with a thick black varnish. The whitish collodion coated areas paired with the black varnished areas caused the photographic negative to appear as a positive image when viewed by reflected light.