How every bubble sheet is verified

Before a sheet is published, the build draws it, reads it back with a different program, and measures it. If any check fails, the site does not build. This page lists exactly what is checked, and is equally clear about what is not.

What the build checks

For every page of every PDF:

1. The page is the size the layout says it is. Width and height must be within 0.5 point (0.18 mm) of US Letter or A4, and the page count must match the plan.
2. Every bubble the layout asked for is there. Each is probed at its planned position and must be drawn as a ring with at least 90% of its circumference dark, with its measured center within 0.9 point (0.32 mm) of where it was planned.
3. The four corner squares are filled, so a stack can be aligned and a reader can find the page.
4. Nothing is printed too close to an edge. All ink must be at least 13 points (4.6 mm) from every side, so a printer with a wide unprintable margin does not clip it.
5. Bubbles line up in rows and in columns, with no duplicate row positions and no bubble with ink just outside its own radius, which would mean two overlap.

How it is checked

One layout engine plans each sheet. A PDF library writes it. Then a different library, the PDF.js renderer, draws the finished file at 3 times 72 dpi and the checks above probe the pixels. Using a separate reader matters: if the writer mis-wrote something in a way it would also mis-read, a self-check would pass and the sheet would still be wrong.

What is covered

All 34 ready-made sheets, and 38 layouts that no template uses but the generator can produce:

• 300 questions / 2 columns (multi-page)
• 300 questions / 4 columns (multi-page)
• 1 question / 1 column
• 200 questions / FGHJ / 4 columns
• 50 questions / True-False / A4
• 37 questions / 3 columns / A4
• 15 questions / 4 sheets per page
• 20 questions / 4 sheets per page
• 25 questions / 2 sheets per page
• 25 questions / 4 sheets per page / A–E
• 25 questions / 2 sheets per page / Student ID
• 40 questions / alternating A–D, F–J / 2 columns
• 200 questions / alternating A–E, F–K / 4 columns
• 50 questions / watermark + signature line
• 100 questions / A–E / Student ID / watermark + signature
• 20 questions / 4 sheets per page / watermark + signature
• 10 questions / 2 sheets per page / signature line
• 150 questions / 3 columns / multi-page / watermark + signature
• 40 questions / team header / A4 / watermark
• 60 questions / alternating A–E, F–K / signature line
• 50 questions / Test Form bubbles + instructions banner
• 100 questions / A–E / Student ID / form bubbles + instructions
• 40 questions / no header / form bubbles + instructions
• 10 questions / 4 sheets per page / form bubbles + instructions
• 20 questions / 2 sheets per page / form bubbles + instructions
• 20 questions / 2 lined FRQ boxes
• 25 questions / 4 lined FRQ boxes / signature line
• 30 questions / 3 math work-area boxes
• 22 questions / 6 grid-in boxes
• 20 questions / 8 grid-in boxes + 2 lined FRQ + form + instructions
• 40 questions / 4 grid-in boxes / A4
• 150 questions / 3 columns / 6 grid-ins / multi-page
• 50 questions / Student ID / pre-filled name and ID
• 100 questions / A–E / 9-digit ID / pre-filled, short ID
• 40 questions / pre-filled name, basic header, A4
• 15 questions / every header and footer block on at once
• 30 questions / Student ID + banner + form + honor line / A4
• 300 questions / pre-filled / multi-page

The generator builds its PDFs in your browser from the same engine, so those layouts share the geometry that was verified, but the PDF you download from it is not itself run through these checks.

What this does not prove

• That your printer will print it correctly. Paper, margins and driver settings are not simulated.
• That any grading app or scanner will read it. No grading product has been tested, and none is claimed to work.
• That it looks right to you. The checks are numeric. Please print one copy and look.

That last point is the one that matters. Print a sheet at 100%, measure the corner squares (they should sit about 5 mm (3/16 inch) from each edge), fill in a known pattern and grade it before you run a class set. The printing guide shows how.

Printer and browser test prints

None have been published. Nobody has yet recorded a real printout of these sheets on this page, so this site makes no claim about how any particular printer or browser reproduces them. If that changes, the measurements will appear here exactly as recorded.

Last updated October 30, 2026. See also the about page and the disclaimer.