bleu détouré

OBS: Détourage : Opération qui consiste à délimiter exactement le contour d'un sujet sur un cliché photographique et à rendre opaque la partie inutile.

CONT: These sheets are printed with dropout blue layout lines.
OBS: The drop-out halftone is made where it is desirable to eliminate the highlight background of an illustration. The most effective way of producing such an illustration is to opaque out the background by painting in the unwanted areas on the negative.