Underbase turns the artwork customers actually send into everything your press needs: one plate per ink, a white underbase choked so it never peeks out, true-size film with registration marks, and a production ticket. Open the file, confirm the inks, click Generate. No Photoshop, no plug-in, no subscription. WHO IT IS FOR The owner-operator of a small custom-apparel shop running a manual or small automatic press, printing spot-color jobs of two to six inks on dark and light garments. When a customer sends a JPEG logo and you need film by this afternoon, Underbase is the tool. WHO IT IS NOT FOR Photographic simulated-process separations (those need a Photoshop-based tool), RIP queues and printer drivers, ink-coverage quoting, and general image editing. Underbase does one job well. WHAT YOU GET - A white underbase with choke. Built from the inks you choose and pulled in by the millimeter so no white shows at the edges on dark garments. Dark inks can print straight on the shirt. - A plate budget with one-click fit. Tell Underbase how many screens your press has; it counts the underbase and every printing ink, warns when a job runs over, and merges the closest inks down to fit. - A production ticket, as PDF and JSON: print order, mesh, offsets, coverage per plate, garment, quantity, due date, notes and sign-off boxes. - Gang sheets. Small designs put several plates on one sheet of film, each with its own registration marks and label, so film is not wasted. - Index mode for soft artwork. JPEG logos, shadows and gradients are dithered across a fitted set of inks, the classic index-separation technique, with a strength control. - The files customers send: PNG, TIFF, JPEG, BMP, GIF, WebP, SVG, PDF and PDF-compatible Illustrator (AI) files, up to 50 megapixels. Vectors are rasterized at 300 dpi. - Inks you confirm. Underbase assigns anti-aliased edges to the nearest ink, groups close shades and leaves the background fill unprinted; you rename, merge, reorder or switch off any ink before anything is generated. - Trapping. Spread or choke any plate, or trap every ink under the darkest in one click, with the amount shown in millimeters and in pixels at your artwork's resolution. - Halftones that match the mesh. Screen any plate at your own ruling, angle and tint, take the ruling suggested from the mesh count, and thin the dots by the dot gain you measure on press. - A suggested print order: light to dark, black next to last, white on top as the highlight white. - Film output every way a shop needs it: a 1-bit film TIFF per plate at 600, 720, 1200 or 1440 dpi, unscreened channel TIFFs for other tools, a true-size film PDF on Letter to A2 or a custom sheet, mirrored for emulsion-down output, or printed straight to a Windows printer. - Output dots preview. See the plate exactly as the film will carry it, at the output resolution, before you burn a screen. - Inches or millimeters, undo and redo, protection against losing unsaved edits, saved and recent jobs, and built-in help on choke and trap, mesh to ruling, film density and troubleshooting. HOW IT WORKS 1. Open or drop artwork. 2. Confirm the inks, the underbase and the plate budget in the live preview. 3. Pick the film size, resolution and output folder. 4. Generate. Film PDF, TIFF plates, channels, preview and ticket land in one job folder. A word on film density: Underbase writes 1-bit plates and PDF; how black they print is up to your printer. Inkjet film needs a RIP or a dense-black driver setting, and the film-density help page says what to check before you burn a screen. PRIVATE BY DESIGN Underbase runs entirely on your PC and makes no network connections: no account, no upload, and no telemetry of its own (the Microsoft Store collects its usual install data). Even links inside customer SVG files are removed before the file is drawn. Your artwork, jobs and output stay in the folders you choose.