Screentone Pattern Maker

What it is for

Screentone Pattern Maker creates repeatable shading patterns for comic backgrounds, clothing or design studies. Choose dots, parallel lines or perpendicular crosshatch, then set cell pitch, nominal coverage, angle and print resolution.

The output includes a vector SVG swatch and a reusable tone recipe. You can open a tone study in Flipline Comic Desk, or import the recipe into an existing page to shade a selected panel. These are independently implemented geometric patterns inspired by MediBang's materials workflow, without copying its material library.

Worked example

Keep the defaults: dots, 14 px pitch, 20 % coverage, 45° angle, 150 DPI and a 600 × 400 px swatch. The tool answered "A 20% nominal dot tone at 10.71 lines per inch." 150 DPI / 14 px = 10.71 LPI, and the swatch prints at 101.6 × 67.7 mm. In the 406-byte SVG every 14 px cell holds one dot of radius 3.5324 px, because 14 × √(0.20 / π) = 3.53; that dot covers 39.2 of the cell's 196 px², exactly 20 %. The 226-byte tone recipe keeps pitch, coverage, angle, ink and DPI. In Comic Desk, select a panel and open the recipe through Open comic project; the tone lands on that panel and can be edited or undone.

The crosshatch example uses 35 % coverage, 20 px pitch and no rotation: "A 35% nominal crosshatch tone at 7.50 lines per inch." Each stripe is 3.8755 px wide, from 20 × (1 − √0.65). Two stripes of that width cover 1 − (1 − 0.194)² = 35 % of a cell once their overlap is counted; giving both stripes 35 % width (7 px) would cover about 58 %.

How to read the result

Pitch is the repeated cell size in source pixels. Nominal lines per inch equals DPI divided by pitch. Physical size equals pixels divided by DPI and multiplied by 25.4. The SVG encodes its physical size in millimetres.

Dot radius is pitch multiplied by the square root of coverage divided by pi. Line width is pitch multiplied by coverage. For crosshatch, stripe width is pitch multiplied by one minus the square root of one minus coverage. Rotation changes orientation while preserving nominal geometric coverage.

Coverage describes ideal vector area, not measured ink density or perceived darkness. Antialiasing, paper, printer dot gain and the chosen ink color affect the final appearance.

Tips and common mistakes

Keep vector patterns as vectors until final output when possible. Resizing a rasterized tone can cause moiré. Avoid overlapping similar fine patterns without checking the result at the intended output scale.

Coverage ranges from five to seventy-five percent, pitch from four to eighty pixels and angle from minus ninety to ninety degrees. Swatch dimensions are 64–1600 pixels per side. Resolution is 72–600 DPI.

A tone recipe imported into a page with another DPI rescales pitch to preserve nominal lines per inch. If that conversion exceeds the supported pitch range, the editor rejects it rather than changing the frequency silently. Adjust the source recipe or page resolution.

FAQ

Does higher DPI create more dots automatically?

At fixed pixel pitch it increases nominal lines per inch and reduces physical swatch size. To preserve print frequency at a higher DPI, increase pitch in the same proportion.

Is the pattern a transparent cutout?

The standalone swatch has white paper for inspection. In Comic Desk, a panel tone is composited over its panel paper, either below or above artwork. Balloons remain above the artwork and tone.

Can an agent generate tones?

Yes. Use the JSON API or MCP tool flipline_screentone, with direct fields pattern, pitch, coverage, angle, dpi, width, height and ink. Download the recipe for editable reuse rather than relying on a flattened screenshot.