a blue-toned photographic print used as a proof for platemaking
blueline in American English
(ˈbluˌlaɪn)
noun
Printing
a final proof made on photosensitive paper from negatives used in offset printing
: also blueline print
blueline in American English
(ˈbluːˌlain)
noun
Printing
a print made on light-sensitive paper and used as a proof for checking the position of stripped-up negatives or positives and copy prior to platemaking