A PDF can look correct on screen while its printed dimensions change. Automatic fitting is useful for readable handouts, but it can make a cutting template, positioning guide or other size-sensitive document unsuitable for its intended purpose.

Find where scaling enters the job

Check the document author's instructions for the required paper and scale. Use a PDF viewer that exposes page sizing instead of relying on a simplified preview. Acrobat distinguishes fitting a page to the printable area, shrinking oversized pages and selecting a custom scale.

For a document requiring one-to-one output, choose the unscaled or Actual size option where available, and inspect the printer driver's own sizing controls. Avoid setting a fitting option in one place and assuming another application's 100 percent setting will override it.

The paper size in the job must match the physical stock. If the design extends outside the printer's printable area, unscaled output may clip it. The solution may be larger supported paper or a documented tiled-print workflow, rather than silently shrinking the pattern.

Measure a disposable proof

Print a single copy and measure a known horizontal and vertical reference with a suitable ruler. Prefer the calibration square or scale bar provided by the author. Do not use the outside paper edge as evidence that the artwork retained its scale.

Inspect the complete page for missing borders or annotations. A correctly sized centre feature does not prove that the margins printed. If accuracy is critical to a fitting or installation task, apply that task's own measurement requirements; a home print setting is not a calibration certificate.

Keep the accepted output with a note of the PDF version, printer and sizing choices. Recheck after changing software, paper size or printer, because a saved default can introduce fitting again. Do the inexpensive measurement before cutting material or ordering anything based on the printed dimensions.

Sources: Adobe page scaling reference.