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Guided workflow variation

Film positives at true size,with the dots you set.

Underbase screens each plate at the ruling and angle you choose, thins halftones for the dot gain you measure on press, and writes 1-bit TIFFs plus a film PDF with identical registration marks on every page, ready for your film printer.

Set the ruling, angle, and dot gain, check the output dots, pick the film size, and generate 1-bit TIFFs and a true-size film PDF.

Pay once. Own it forever.

One-time purchase on the Microsoft Store · No subscription · Instant install

Get it from Microsoft

Buy through the Microsoft Store—instant install, automatic updates, and a Microsoft receipt for easy expensing. No account needed on our site, and no subscription on Store purchases.

Full Underbase overview
One-time purchase No telemetry Local-first

windows · runs on your pc · no account · nothing uploads · 15-day free trial

If this sounds like your week

Getting dots onto film is its own craft.

A separation is only useful once it is a positive the exposure unit can burn. Halftone plates need a line count that suits the mesh, an angle that avoids moiré, and tones adjusted for the spread that textile ink adds once it soaks into cotton. Then every sheet needs matching targets, a readable label, the right scale, and, for some film printers, a mirrored image.

Where tooling usually breaks

Film mistakes show up only after exposure.

A positive printed at 97 percent because a driver scaled it to fit the page will not register with its siblings. Midtones that looked right on screen fill in and go muddy once the press adds gain. A sheet without a label sits in a pile next to five others, and someone has to guess which frame it belongs to, often after the emulsion is already exposed.

Where Underbase lands

Screen, compensate, size, mark, and label in one step.

Underbase sets screening per plate: Halftone this plate, Screen ruling from 10 to 120 lpi, and Screen angle, or Suggest ruling from mesh. Dot gain compensation thins halftone plates by the mid-tone gain you enter. The film PDF is checked against the sheet you load, with identical targets, center ticks, and a label naming job, plate, ink, screening, offset, and mesh. Mirror handles emulsion-down output.

Pay once. Own it forever.

One-time purchase on the Microsoft Store · No subscription · Instant install

Get it from Microsoft

Buy through the Microsoft Store—instant install, automatic updates, and a Microsoft receipt for easy expensing. No account needed on our site, and no subscription on Store purchases.

Learn more about Underbase

windows · runs on your pc · no account · nothing uploads · 15-day free trial

What you get

Feature highlights

Spot or index separation from the files customers send

PNG, TIFF, JPEG, BMP, GIF, WebP, SVG, PDF, and Illustrator (.ai) files, with close shades grouped, the background left unprinted, and shaded art dithered between a fitted set of inks.

A choked white underbase

built from the inks you tick, pulled in from 0 to 3 mm in 0.05 mm steps, with dark inks printing straight on the shirt and a preview on seven garment colors.

Trapping in one click

spread or choke any ink from -3 to +3 mm, or apply the default trap to every ink so lighter colors tuck under the darkest.

Halftones tuned to your press

screen any plate at your ruling, angle, and tint, take a ruling suggested from the mesh, thin halftones for measured dot gain, and check the output dots before film.

A plate budget you can see

Underbase counts the underbase and every printing ink against the screens your press holds, holds generation until the job fits, and merges inks to fit in one click.

True-size film and a production ticket

a film PDF with identical registration marks and plate labels, one plate per sheet or ganged, 1-bit TIFFs at up to 1440 dpi, and a ticket as PDF and JSON.

Especially when

  • Turn a customer PNG, JPEG, SVG, PDF, or Illustrator file into one plate per ink without selecting colors by hand in a design program
  • Build a white underbase for dark shirts that is choked so it never shows at the edges, and keep dark inks off it
  • Know the plate count before burning a screen, and merge inks to fit the screens the press holds
  • Print film positives at true size with registration marks and plate labels, plus a production ticket, without sending the job to an outside separator

Who benefits

Real-world scenarios

A full-front print on Super B film

The shop prints film on a 13 x 19 in inkjet and needs a 10 x 12 in front print for four screens: the underbase and three inks.

With Film size set to Super B, the Film tab reports that the 10 x 12 in artwork with registration marks fits Super B 13 x 19 in. The film PDF has four pages, one per plate, each with the same marks and a label such as Plate 2 of 4: Navy.

A left-chest crest ganged on one sheet

A 4 x 4 in two-color crest needs three screens, and printing three nearly empty sheets of film for it wastes film and ink.

With Sheet layout set to Gang plates on each sheet, the Film tab shows six slots per Super B sheet, each with its own registration marks and label. The three plates share one sheet, ready to cut apart for the screens.

Emulsion-down film for the exposure unit

The shop exposes its screens with the film emulsion side against the mesh and needs the positives printed mirror-image, with labels that still read correctly once flipped.

The operator turns on Mirror (emulsion down). The film TIFFs and PDF are flipped, the labels are mirrored with them, and the footer of every sheet records Mirrored (emulsion down), so the film room can tell at a glance which way the sheets were printed.

Deep dive

From plate to film: screening, dot gain, sizing, and marks

Solid or halftone, per plate. Spot inks print solid by default. Select an ink and turn on Halftone this plate to screen it at a Screen ruling from 10 to 120 lpi and a Screen angle from 0 to 90 degrees, with a tint when the whole plate should print lighter. The underbase has the same controls. Suggest ruling from mesh sets the ruling from the mesh count at 22.5 degrees and turns the halftone on, and the Mesh field reminds you that halftones want at least four times the line count in mesh.

Dot gain compensation. Ink spreads into fabric, so a 50 percent dot prints darker than 50 percent. Enter the mid-tone gain you measure on press in Dot gain compensation, from 0 to 50 percent, and halftone plates are thinned to match; the helper notes that textile work often sees 15 to 30 percent. Solid plates are left as drawn, and 0 leaves every tone untouched.

Output resolution. Choose 600, 720, 1200, or 1440 dpi under Output resolution (dpi). The default is 720. The helper under the field shows the plate size in pixels at that resolution, and every film TIFF is written at it.

See the dots first. In the Plate tab, turn on Output dots to render the selected plate exactly as it will be output, with real dots at the output resolution. Zoom in to check that highlights hold and shadows stay open before you print a sheet.

Film sizes and fit. Film size offers Letter, Legal, Tabloid, Super B, ANSI C, A4, A3, A3+, A2, and Custom size for any sheet from 2 by 2 to 60 by 120 in. Underbase checks that the artwork plus its marks and labels fits, turns the layout landscape when the art fits that way, and, when the sheet is too small, tells you the largest print width that fits.

Marks and labels. Every plate gets identical registration marks around the art, plus center ticks on each edge to line the film up on the screen. Each sheet carries a header with the job name, plate number, ink and hex value, screening, offset, mesh, and dpi, a large plate number in the corner for sorting at the light table, and a footer with the print size, film, orientation, separation mode, and date.

One per sheet or ganged. Sheet layout puts one plate on each sheet, or gangs as many plates as fit, each with its own marks and label. Mirror (emulsion down) flips the whole output.

What lands in the folder. The film PDF, a 1-bit CCITT Group 4 TIFF per plate in film-tiff, unscreened 8-bit channel TIFFs in channels, the production ticket, and a preview. Print film sends the true-size pages to any Windows printer, and the 1-bit TIFFs go straight to a RIP.

How it is built

Built for the press, not the design studio.

The press sets the limits

You enter the screens your press holds, the mesh, and the dot gain you measure. Underbase counts every plate against that budget and thins halftones to match before any film is written.

Film at true size

Every plate lands on the sheet at true size with identical registration marks, center ticks, and a label naming the job, plate, ink, screening, offset, and mesh.

Nothing uploads

Underbase runs entirely on your PC with no account, no telemetry, and no network connections. Customer artwork is only read. One-time purchase in the Microsoft Store.

Head-to-head

How Underbase compares

Feature Underbase Printing from a design app Outside film service
True size on the sheet Yes, with a fit check against the film size you pick Depends on print and scaling settings Yes
Registration marks Identical marks and center ticks on every plate Placed by hand Yes
Plate label Job, plate, ink, screening, offset, mesh, and dpi Typed by hand Varies by service
Dot-gain compensation From the mid-tone gain you measure, 0 to 50 percent Separate curve work Varies by service
Ganging small designs Gang plates on each sheet, each with its own marks and label Arranged by hand Varies by service
Turnaround Generated on your PC and printed in-house In-house Shipping or pickup

FAQ

Straight answers—no glossary dump

What resolution should film positives be?

Underbase writes film at 600, 720, 1200, or 1440 dpi, with 720 as the default. Higher settings render finer halftone dots and write larger files. Pick the resolution under Output resolution (dpi); the helper shows the plate size in pixels, and every 1-bit TIFF and the film PDF images are written at that resolution.

What is dot gain compensation, and how do I set it?

Dot gain is the growth of halftone dots as ink spreads into the fabric, which makes midtones print darker than on screen. In Underbase, enter the mid-tone gain you measure on press in Dot gain compensation, from 0 to 50 percent. Halftone plates are thinned so the printed tone matches the artwork, while solid plates stay as drawn. Textile printing often sees 15 to 30 percent.

Can several plates share one sheet of film?

Yes. Set Sheet layout to Gang plates on each sheet, and Underbase places as many plates as fit on the film size you chose, each with its own four registration marks and its own label. The Film tab shows the layout and how many plates fit per sheet, for example six 4 x 4 in plates on one Super B sheet.

Can I print film straight from Underbase?

Yes. Print film in the toolbar sends the true-size film pages to any Windows printer through the standard print dialog, one plate per page or ganged, mirrored if you chose emulsion-down output. For an inkjet film printer driven by a RIP, send the 1-bit TIFFs from the film-tiff folder, which are already screened at the output resolution.

Does my customer's artwork stay on my PC?

Yes. Underbase runs entirely on your PC. There is no account, no upload, and no telemetry, and the app makes no network connections. It reads the artwork you open, writes each job to a folder inside the output folder you choose, and keeps its own settings in local app data. Jobs save as .underbase files you can reopen for a repeat order.

How do I get Underbase, and is there a trial?

Underbase is a one-time purchase in the Microsoft Store, and the listing shows the current price in your currency. The Store runs a 15-day free trial, so you can separate a job you have already printed, or one of the six bundled samples, and compare the film with what you burned. The Store installs and updates the app. It runs on Windows 11 version 24H2 or later on x64 PCs.

Related pages

A white underbase for dark shirts, choked so it stays hidden. From customer art to film, in one separation app. Gradients and soft shadows, printed with a handful of inks.

Customer art in.
Press-ready film out.

Underbase separates flat and shaded art into spot inks, builds a choked white underbase, traps colors in one click, keeps the job inside your plate budget, and writes true-size film with registration marks and a production ticket. Everything runs on your PC, and the Microsoft Store runs a 15-day free trial.

Pay once. Own it forever.

One-time purchase on the Microsoft Store · No subscription · Instant install

Get it from Microsoft

Buy through the Microsoft Store—instant install, automatic updates, and a Microsoft receipt for easy expensing. No account needed on our site, and no subscription on Store purchases.

Open full product page

Illustrator is a trademark of its owner, registered in the U.S. and other countries. Underbase opens Illustrator (.ai) files as an input format and is not affiliated with or endorsed by the trademark owner.

Technical specifications

Technical specifications for procurement

Spec Implementation
Data Sovereignty Reads only the artwork you open or drop on the window and never writes to it; writes each job (film PDF, TIFF plates, channels, ticket, preview, and .underbase job file) to a folder inside the output folder you choose; settings stay in local app data on this PC
Telemetry Status None; no account, no upload, no telemetry, and no network code in the app
Core Runtime .NET 10 and WPF, self-contained, distributed through the Microsoft Store as an MSIX package; separation, halftoning, TIFF, and PDF output run in the app’s own engine, with PDF and Illustrator (.ai) pages rendered by a bundled PDFium engine
Network Requirements Fully functional offline; the app makes no network connections and nothing is uploaded
Deployment Compatibility Windows 11 version 24H2 or later (10.0.26100), x64; 8 GB RAM recommended for very large artwork, about 400 MB of disk; one-time purchase in the Microsoft Store with a 15-day free trial
Inputs PNG, TIFF, JPEG, BMP, GIF, WebP, SVG, PDF, and Illustrator (.ai) files; vectors rasterised at 300 dpi at true size; print size from the file’s resolution tag or a print width you set, in inches or millimeters
Separation Spot mode (one ink per flat color, close shades grouped, background left unprinted) or index mode (error-diffusion dither between a fitted ink set, dither strength 0 to 100); reduce to 1 to 16 inks; rename, merge, reorder, or switch off any ink
Underbase and traps White underbase from the inks you choose, choke 0 to 3 mm; spread or choke per ink from -3 to +3 mm; one-click trapping of every ink under the darkest; suggested print order with highlight white
Screening Solid or halftone per plate at 10 to 120 lpi, any angle, with tint; ruling suggested from mesh count; dot-gain compensation from 0 to 50 percent; output dots preview at the output resolution
Outputs True-size film PDF with registration marks, center ticks, and plate labels, one plate per sheet or ganged, mirror for emulsion down; 1-bit CCITT G4 film TIFF per plate at 600, 720, 1200, or 1440 dpi; unscreened 8-bit channel TIFFs; production ticket as PDF and JSON; preview PNG; .underbase job file
Film sizes Letter, Legal, Tabloid, Super B, ANSI C, A4, A3, A3+, A2, or a custom sheet up to 60 x 120 in; direct printing to any Windows printer