A CLI that takes a PDF and degrades it to look like a physical scan of a printout — skew, grayscale, warm paper tone, scanner grain, defocus, edge shadow, and JPEG compression artifacts. Also runs client-side in the browser via WASM.
Each page is rasterized to an image, run through the effect pipeline, and reassembled into a new image-only PDF (the original selectable text is gone — faithful to a basic scanner).
Build
Requires Go and a C toolchain (go-fitz links MuPDF via cgo, so the binary is self-contained — nothing to install at runtime).
go build -o make-look-scanned .Usage
make-look-scanned [flags] input.pdf
Flags may appear before or after the input filename.
make-look-scanned in.pdf # -> in.scanned.pdf
make-look-scanned in.pdf -o out.pdf
make-look-scanned in.pdf --noise 0.4 --skew 2.5 --jpeg-quality 30Flags
| Flag | Default | Meaning |
|---|---|---|
-o |
<input>.scanned.pdf |
output path |
--preset |
— | named preset from config.toml |
--seed |
content hash | random seed (override for a new look) |
--force |
false | overwrite an existing output file |
--dpi |
150 | render resolution |
--skew |
0.6 | max rotation degrees (0 disables) |
--grayscale |
true | desaturate (--grayscale=false keeps color) |
--paper-tone |
0.6 | warm paper tint strength 0..1 |
--noise |
0.08 | scanner grain 0..1 |
--blur |
0.4 | defocus gaussian sigma |
--edge-shadow |
0.15 | border vignette 0..1 |
--jpeg-quality |
70 | JPEG quality 1..100 |
Each numeric knob disables its effect at 0.
Determinism
Output is deterministic by default: the seed is derived from the input
PDF's content, so the same file always produces the same scan. Pass --seed N
for a different (but reproducible) look. Same input + seed yields a
byte-identical PDF.
Presets
Define reusable bundles in
$XDG_CONFIG_HOME/make-look-scanned/config.toml (falls back to
~/.make-look-scanned/config.toml when XDG_CONFIG_HOME is unset). Keys
mirror the flag names with underscores:
[presets.medium] skew = 1.5 paper_tone = 0.6 noise = 0.2 blur = 0.6 edge_shadow = 0.3 jpeg_quality = 45
make-look-scanned --preset medium in.pdf
Precedence: built-in defaults → selected preset → explicit CLI flags (flags always win).
Browser (WebAssembly)
The effect pipeline also runs in the browser. go-fitz/MuPDF can't compile to wasm, so the browser uses PDF.js to rasterize pages and hands the pixels to the same Go effects + assembly code compiled to wasm.
Dev (needs network for the PDF.js CDN):
./web/build.sh # builds web/main.wasm + wasm_exec.js (cd web && python3 -m http.server 8080) # then open http://localhost:8080
Single self-contained file (works offline, nothing to serve):
task build:web # writes dist/make-look-scanned.html (~8 MB)dist/make-look-scanned.html inlines the wasm, Go's runtime glue, and PDF.js
(library + worker) as base64 — open it directly in a browser. Output is
visually equivalent to the CLI but not byte-identical, since PDF.js and MuPDF
rasterize differently.
License
AGPL-3.0. The CLI statically links MuPDF (via go-fitz), which is AGPL-3.0, so the combined binary is AGPL-3.0 — distributing it requires offering the corresponding source. The browser build does not include MuPDF (it uses PDF.js, Apache-2.0).