Print a PDF at 100% without changing its size

A PDF can contain exact physical dimensions while the printed result is a different size. The print dialog and device driver may resize it to fit paper or the printer's printable area. Before using a measured alignment correction, check size separately from position.

Match the document and the paper

A4 measures 210 × 297 mm. US Letter measures 215.9 × 279.4 mm. Those rectangles are different shapes. Sending an A4 file to Letter paper with a fitting option can change scale or crop part of the page. Choose a matching PDF and sheet size rather than treating the two names as interchangeable.

BackAlign reports the page dimensions after opening a file. Its calibration presets include A4, Letter and A3, in portrait or landscape. The PDF correction preserves the input dimensions; choosing a calibration preset does not convert an imported file to that size.

Separate scale from page placement

In Acrobat, the actual-size choice prints without scaling, while fit resizes the page to the available printable area. Other viewers use different names. Check both the application's dialog and the printer's settings. Borderless modes can enlarge artwork to cover the sheet edges, so they are unsuitable for a measured actual-size test unless their behavior is understood.

A printer can still clip content outside its printable area even at correct scale. Correct size does not imply that every page edge is printable. Keep the test's reference marks away from the edge and inspect the physical proof.

Measure the reference before the offset

The calibration PDF contains a 50 mm reference line. Measure between its end ticks with a physical ruler. If it is substantially different from 50 mm, investigate scaling first. The live browser illustration is magnified and is not an on-screen measuring instrument.

For example, a line intended to be 50 mm that prints as 48 mm has a scale ratio of 48 ÷ 50 = 0.96. Moving the back page cannot fix this 4% scale difference. A shift can align one point while leaving marks farther away mismatched.

Print a single front/back pair

Use the same paper, orientation, tray and flip setting as the final job. Avoid additional multiple-pages-per-sheet, booklet or automatic rotation options while testing a normal two-page pair. If you need imposition, measure and verify that complete setup rather than assuming this tool knows the driver's transformations.

After size and orientation are correct, measure the back marks through the front. Compare the corners as well as the center. A consistent difference may be suitable for translation; changing differences deserve further diagnosis.

Record what worked

Save the settings with your own note about printer, paper and tray. BackAlign's settings file stores no PDF content and does not automatically retain a copy in browser storage. Repeat the test after a material change. Software coordinates alone cannot verify physical printing.

References and verification

Adobe: PDF print sizing options. Geometry and worked examples on this page are BackAlign’s own calculations. Digital PDF transformations are tested; physical printer output has not been verified.