MINSULA PRINT LAB / FIELD NOTES

How Print Lab calculates physical PDF layouts

All layout calculations use millimetres. The PDF writer converts millimetres to points with 72 ÷ 25.4. A4 is 210 × 297 mm; US Letter is 215.9 × 279.4 mm. Landscape swaps the paper dimensions. CSS preview pixels are never used to establish print size.

One geometry model

The preview and PDF use the same image rectangles and clipping windows. Single mode centres the image in the usable region and refuses oversized images. Repeat mode uses floor((usable + gap) ÷ (image + gap)) on each axis, filling rows left to right. Tile mode advances by usable size minus overlap and clips the full-sized image separately on every page.

The footer reserves 12 mm with the optional verification line, or 6 mm for labels alone. A line is exactly 100 mm when it fits; otherwise it is omitted with a warning. The PDF requests no viewer scaling, but your print dialog can override that preference.

Raster handling

PNG, JPEG and WebP headers are checked before browser decoding. Limits are 20 MiB, 24 million pixels and 12,000 pixels on either side. Transparency is flattened to white. Browser decoding handles orientation; the optional rotation then turns the decoded artwork clockwise. A high-quality JPEG is embedded once and reused on PDF pages. Animated inputs should be exported as a still image for predictable results.

Practical limits

Image dimensions are limited to 0.1–2000 mm per side, copies to 200 and PDFs to 36 pages. This is a raster craft tool, not a vector editor, colour proofing service or calibrated measuring instrument.

Verification

Automated checks cover geometry, error handling and PDF structure. A physical printer test remains necessary for your own printer, driver and paper. Measure the 100 mm line before relying on a cut template.