A photoblocker is any opaque material applied to film negatives or masking sheets to prevent ultraviolet light from reaching the printing plate during the exposure process. Prepress technicians use liquid opaque to paint out pinholes, dust marks, or unwanted image areas on a negative so they do not expose and print on the final piece.
Heard on the job
Paint some photoblocker over that scratch on the negative before you burn the plate.
Also heard as
- opaque
- blockout