How the vector printer test sheets are built

One canonical geometry model

Lines, rectangles, circles, and short text labels are defined once in physical page coordinates. The SVG preview reads those primitives directly. Browser print uses the same SVG with millimeter dimensions and static named-page CSS. The PDF renderer converts millimeters to PostScript points using 72 ÷ 25.4 and writes the same primitives into a one-page content stream.

This eliminates a common class of mismatch where a decorative preview, an unrelated image file, and a PDF drift apart. It does not make the screen physically accurate: viewport size, pixel density, zoom, and browser layout still change on-screen dimensions.

• A4: 210 × 297 mm
• Letter: 215.9 × 279.4 mm (8.5 × 11 in)
• Legal: 215.9 × 355.6 mm (8.5 × 14 in)
• Scale references: 100 mm and 4 in (101.6 mm)

Why the PDF is deliberately simple

The generated file is a passive PDF 1.4 with one page, standard Helvetica fonts, vector drawing commands, and an exact MediaBox. It contains no JavaScript, automatic actions, forms, attachments, remote resources, links, printer identifiers, personal metadata, or variable creation timestamp. A SHA-256 hash is shown after download so deterministic output can be compared.

PDF generation occurs only after the user clicks Download. The file is assembled in memory and offered through a temporary browser Blob URL. That URL is revoked; the application does not upload or retain the PDF.

A machine-readable registry at /pdf-hashes.json publishes the SHA-256 value and byte size for every selectable version 1.0 PDF combination. Matching a hash identifies the deterministic file bytes; it does not validate a printer, print dialog, or physical result.

Ink restraint and its tradeoff

Low ink is the default. It uses narrow labeled patches, fine rules, outlines, and limited marks rather than full-page saturated fields. The displayed coverage value is calculated from vector geometry so modes can be compared; it is not a promise or measurement of real ink or toner consumption.

Small patches may miss subtle density, uniformity, or intermittent faults. Standard mode intentionally enlarges certain patches and line groups but still avoids a full-page solid. Users should not repeat high-coverage tests indefinitely.

Recommendation and language rules

Recommendations begin with one of six observed symptoms. Technology is requested only when it changes the sheet or interpretation. Inkjet guidance may discuss visible line continuity and documented maintenance; laser guidance discusses density, repetition, and registration without calling those features “nozzles.” Not sure stays technology-neutral.

Interpretation is structured as observation, possible causes, safe next step, and stop condition. The wording does not claim professional calibration, universal compatibility, a confirmed faulty part, a successful physical print, or guaranteed savings.

Privacy and security model

The critical workflow has no upload control, printer enumeration, hardware API, advertising script, third-party image, or remote generation endpoint. Choices remain component memory and are not written to the URL, Google Analytics events, cookies, localStorage, or sessionStorage. The product does not need a printer name, serial, local address, queue, scan, photo, or document content.

Google Analytics G-KYLNKKWB03 measures ordinary page visits separately from the diagnostic state. The content-security policy allows only the application and the approved Google Analytics hosts, while framing, plugins, remote images, ads, and custom diagnostic events remain blocked.

Validation status and open gate

Automated checks cover recommendation branches, dimensions, geometry, vector/PDF consistency, passive-PDF tokens, deterministic hashes, user workflows, keyboard access, responsive layouts, policy artifacts, metadata, and production builds. Local PDF tools can inspect the page count, MediaBox, fonts, attachments, and rendered appearance.

Automation cannot certify a physical printer. Before public release, representative inkjet and laser devices should print A4 and Letter from current Chrome, Safari, Preview, and Acrobat paths; rulers should verify both reference lengths. Legal needs a Legal-capable device and remains labeled “Not physically validated” until that evidence exists.