Film Output and Traditional Prepress: What Still Needs Film
What film output was
For decades, prepress meant film. An imagesetter rasterised the page into halftone dots and exposed them onto high-contrast photographic film; that film was then contacted onto the plate or screen. Film was the universal intermediate between the digital file and the physical printing surface.
It was capable, but every job carried film cost, darkroom or processor chemistry, and the registration and density losses of a contact step.
The film workflow
The chain ran RIP to raster, expose film, develop, inspect density, then contact-expose the plate or screen under controlled light. Each step was a chance to drift: film stretch, dust, pinholes and uneven contact all showed up as print defects.
Where film still survives
Film has not vanished. Some legacy shops, certain screen and flexo operations, and a few specialist or regulated processes still depend on it because the installed base, tooling or certification has not been re-qualified on digital. It also remains a fallback where a digital plate or screen path is unavailable or uneconomic.
- Older presses and screens qualified only on film
- Some flexo and speciality shops keep a film capability
- Disaster-recovery and certification holdouts
Why digital replaced it
Computer-to-plate and computer-to-screen remove the film step entirely: the file goes straight to plate or screen, so there is no film to buy, store or contact, and registration becomes digital rather than mechanical. Less chemistry, less waste, fewer drift points and faster turnaround are why most prepress went film-free.
- No film, chemistry or darkroom in the normal path
- Digital registration beats contact registration
- Faster changeover and lower per-job cost
Keeping a film capability
If you must keep film, isolate it to the jobs that truly need it and treat the imagesetter as retained tooling, not your primary path. Modernise everything else first, and keep film as a qualified fallback so it does not quietly become a bottleneck.
The migration path
The pragmatic route is to adopt CTP for plate work and CTS for screen work, migrate the high-volume jobs first, and retire film exposure as the legacy work tapers. McLantis thermal CTP and computer-to-screen systems are built to take that step without re-tooling the whole prepress room at once.