PDF Page Layout — Resize, Crop, Page Numbers & Watermark

No. Each source page is embedded into the new page as vector content and drawn scaled — the same mechanism PDF viewers use — so text, lines, and shapes remain mathematically sharp at any zoom. Nothing is converted to an image. Embedded photos scale with the page like they would on a photocopier.

A4 (210 × 297 mm) is narrower and taller than US Letter (216 × 279 mm). A PDF laid out for one and printed on the other either gets auto-shrunk by the printer driver or clipped at an edge — classically, the bottom line of a US form disappearing on A4 paper. Converting the PDF itself to the target size removes the guesswork from the print dialog.

Fit (the default) preserves the content's proportions and centers it, adding small even bars if the aspect ratios differ — this is almost always what you want, since nothing gets distorted. Stretch fills the target page exactly but changes proportions when the source and target aspect ratios differ, which visibly distorts text. Use Stretch only when the aspect ratios are close.

Usually not much. Standard PDF cropping hides the area outside your box rather than deleting it, so the underlying content still lives in the file. It looks cropped in every normal viewer, but the bytes are largely still there.

No — it is hidden, not removed, and someone with a PDF editor could restore it. If you need to permanently delete sensitive content, use a redaction tool instead of cropping.

Five formats: a plain number (1), Page 1, 1 of 10, Page 1 of 10, and Bates numbering with your own prefix, suffix and zero padding, which can also include the date, time, page and total as tokens. Numbers go in any of six positions — top or bottom, left, centre or right — in Helvetica, Times or Courier at the size, colour and margin you set. You can start stamping on a later page and choose the first number, so a cover page stays blank and the count still reads correctly.

No. pdf-lib draws the watermark as a new overlay on each page without touching the original text, fonts, or vector graphics — it simply adds drawing commands to the page content stream. The output PDF is identical to the source except for the added watermark layer, so text stays selectable and print quality is preserved.

PNG and JPG are supported. PNG is strongly recommended for logos because it preserves transparency — the logo will blend cleanly into page content. JPG images always have a solid rectangular background, which looks less polished when used as a watermark. For best results, use a PNG logo with a transparent background at 300+ DPI resolution.

Tile repeats the watermark diagonally across the entire page in a grid pattern. This is the pattern commonly seen on confidential legal documents and preview copies — it makes content difficult to screenshot-and-crop without the watermark being visible. Combine tile position with 30° rotation and 25% opacity for the classic "repeated diagonal label" look.

A visible watermark added via this tool can be removed by anyone with PDF editing software, since it is a drawing layer on top of content. For stronger protection, encrypt the file with PDF Security and rasterize it with the Flatten mode of the form tool. For truly tamper-resistant marking, consider server-side digital signatures — those are cryptographically bound to the document and cannot be altered without invalidating the signature.

For a one-off print on your own printer, the print dialog's scaling is fine. Resize the PDF itself when the file will be printed by someone else (or a print shop), when you need every recipient to get identical output, or when a system downstream expects a specific page size. Print-dialog scaling is a per-print, per-driver setting that silently varies between machines; a resized PDF removes that variable by making the file itself match the paper.

Keep the page size the same as the source, choose Fit, and set the content scale to around 90–92%. The content shrinks uniformly and re-centers, leaving an even margin on all four sides — about 10–12 mm on A4 at 90%, enough for a hole punch or spiral binding without clipping anything. A margin on one side only (a true gutter) is an asymmetric change this uniform scaling doesn't make.

Zoom only changes how you view the file on your screen; it doesn't travel with the document. Cropping changes the page itself, so the trimmed result looks right for everyone, prints without wasted margins, and displays better on small screens and e-readers.

For status stamps like DRAFT or CONFIDENTIAL, place a semi-transparent watermark on top so it's unmistakable but still leaves the text readable — typically 15–30% opacity at a diagonal angle. For brand logos, behind the content at low opacity looks more professional. A watermark should be impossible to miss yet never make the document hard to read.