Limitations¶

lookscanned works within the features of Typst and of PDF. This page lists the resulting constraints.

No blur or perspective¶

Typst has no blur filter and no perspective transform. Bleed and blur are approximated with textured strokes and soft halos. phone-scan rotates the page and adds uneven lighting; the page is never trapezoidal.

Layout and granularity¶

With "page" and "line" granularity, the layout is identical to the clean document.
With "word", each word is boxed. Boxed words cannot be hyphenated, so a justified, hyphenated paragraph may break differently.
With "char", characters move vertically only, which keeps words whole; kerning may change slightly.
"line" moves whole blocks, since Typst exposes no per-line hook.

Mathematics¶

Equations are inked as a whole; fraction bars and radical overlines are lines and do not bleed.
Inline equations follow their paragraph; they are not jittered individually.

Pages without a fixed height¶

Page-sized textures need the page height. With #set page(height: auto), only the paper colour and the tiled grain are drawn.

Page background and foreground¶

scan sets the page background and foreground, replacing earlier values; a later set page replaces those of scan. See Raw textures to combine layers.

`page` and `region`¶

page overrides page-level effects only; ink and text jitter keep the scan configuration. Calls cannot be nested.
region inside a scan document applies the text effects twice.

PDF viewers¶

Textured ink relies on tiling patterns used as text paint, which viewers support unevenly:

Viewer	Result
macOS Preview, Ghostscript	Rendered fully
Poppler-based (Evince, Okular, `pdftoppm`)	Outline drawn as plain ink: text looks bold and smudged

PNG export in Typst 0.15.1

Typst 0.15.1 panics (crates/typst-render/src/paint.rs) when exporting to PNG text whose fill is an image tiling. This is a Typst bug, reproducible without lookscanned. Export a PDF and convert it with Ghostscript:

typst compile doc.typ doc.pdf
gs -dNOPAUSE -dBATCH -sDEVICE=png16m -r300 -dDownScaleFactor=2 -dMaxBitmap=2000000000 \
  -sOutputFile=doc-%d.png doc.pdf

-dDownScaleFactor=2 renders at twice the resolution and halves it: at low resolution Ghostscript widens the thin textured strokes. -dMaxBitmap disables banding, which otherwise leaves blank bands where tilings cross band boundaries.

Fine details on screen¶

Pinholes and the low-legibility halo are narrower than a screen pixel at normal zoom. They show in print and when zooming in.

Repeated words¶

Randomness is derived from stable data, so the same word receives the same inking variation wherever it appears.

`ghosting` and text extraction¶

ink.ghosting adds offset copies of each word. They are tagged as PDF artifacts, but many tools still extract them. The option is off by default.

Compile time¶

Plugins run in an interpreter. Texture generation dominates compile time; a few seconds per page is normal. See Performance.

Accessibility and responsible use¶

The text of a lookscanned document remains real text: it can be selected, searched, copied and read by a screen reader (except with ghosting). The visual result is nevertheless harder to read on purpose, especially for readers with low vision or dyslexia. When the content matters, distribute a clean version alongside; compiling the same source with intensity: 0 produces one.

The package is intended for design, illustration, fiction, games, stage and film props, and testing OCR or document-processing software. Do not use it to forge documents or to pass a generated document off as a genuine scan.