Frame-by-frame film printer with intermittent motion — negative and print advance in sync. Enables precise exposure control and in-lab optical effects like dissolves and fades.
Step printer / Shuttle printer
The step printer works on a simple but precise principle: the negative and positive film advance synchronously in steps, stop — and at this moment, a lamp exposes the image onto the positive film. This is not continuous like with a contact printer, but discrete, frame by frame. You can immediately see this in the operation at the lab printing facility: the characteristic rattling and stopping, the repeated clicking of the shutter. For the cinematographer on set, this specifically means: the printing master can set the exposure differently for each individual frame.
This is the decisive advantage over continuous systems. If your negative has an overexposure in scene 5, the lab technician adjusts the lamp intensity down before frame 5 is exposed — and sets it back to normal for frame 6. This frame-accurate correction was the standard in every serious printing facility for decades, until digital intermediate technology changed the business. The step printer also enabled optical effects directly in the printing facility: dissolves between two negative elements, fades, multiple exposures — all realized through synchronized movement and variable exposure.
Practically, with such a machine, you have significantly higher control over the final image quality than with modern single-light technology, which allows only one exposure per printing process. The disadvantage: it requires time and experience. The machine itself is mechanically robust, but the synchronization must be correct — a worn timing belt and the whole system goes out of sync. In the final years of digital film processing, such machines have become rarer in large studios, but remain indispensable in specialized houses that still print 35mm material. Some cinematographers still swear today that a well-adjusted step printer is equivalent to a DI for color correction — or even superior when it comes to subtle, cinematic grading.