Film Positive

Every color in a screen-printed design needs its own film positive: a sheet of clear film, printed on a specialized inkjet with dense black ink or output on an imagesetter, where areas that will hold ink print solid black and everything else stays transparent. Laid on top of an emulsion-coated screen under UV light, the black areas block light and keep that emulsion soft and washable, while clear areas let light through and harden it permanently. A six-color design needs six separate positives, each representing exactly one layer of ink.

This is the point where print-ready artwork actually earns that description. A file with soft, anti-aliased edges or an unseparated gradient doesn't translate into a usable positive — the film needs crisp, 100% opaque black with clean edges, or the exposure comes out soft and the stencil holds detail poorly. We've sent designs back because a "black" logo was actually a rich-black CMYK build that printed as translucent gray on film, ruining the exposure before a screen even got coated.

For color separation, pros register each positive to the others using registration marks printed in the same spot on every sheet, so when screens are exposed and printed in sequence, every color lands where it should. Vector artwork converted cleanly into spot-color separations makes this fast; a rasterized photo with soft edges makes it slow and error-prone.

Buyers sometimes assume any high-resolution image is "print ready" for screen printing. It isn't, until separated into individual colors and output as opaque-black positives — a photo-quality JPEG needs color separation and halftone conversion first, which is why art fees exist separately from press time.