Photo-offset is a widely used commercial printing method where metal or polymer plates are exposed to high-contrast film negatives or positives using ultraviolet light. The exposed areas become ink-receptive, while the unexposed areas are washed away to hold water. On the press, the plate transfers the inked image to a rubber blanket cylinder, which then offsets it onto the paper.
Heard on the job
The shop transitioned from letterpress to photo-offset in the seventies to handle higher volume work.
Also heard as
- offset lithography
- photo-offset lithography
Do not mix it up with
- Photolithography: Photolithography is the chemical plate-making process itself, while photo-offset is the actual printing method that uses those plates on a press.