Color separation.

Breaking a design into one layer per ink so each can be printed on its own: a film and a screen per colour in screen printing, a named channel per specialty ink on a UV or DTF RIP. ONYX counts it in plates: a process document has four, and every spot colour adds one, so CMYK plus one spot is five. Screen shops choose between methods, and the method sets the film. The UltraSeps output sheet runs simulated process and CMYK at 55 LPI, basic spot colours with no tints at 300 LPI, and index separations with no frequency, angle or dot shape at all, because index art is square pixels rather than halftone dots. CADlink FilmMaker adds a second fork: separations made in the design application and imported, or made in the RIP. The seller rarely separates the file, but the file decides what is possible. A flattened JPEG of a photo has to be separated as raster, by simulated process, CMYK or index, and cannot go as clean spot colour; a soft drop shadow in otherwise flat art has to be halftoned into the screens around it. Ask which method the shop runs before the art is final, not after the films are burned.