A stamp and a background sit at opposite ends of the same stack — one on top of the page, one beneath it — and behave very differently.
Over the page or under it
Everything in this subject reduces to that one question.
A stamp — APPROVED, a tick, a circle round a paragraph — is an annotation. It sits in the annotation layer above the content, so it can be dragged, recoloured and deleted by anyone. Some readers do not print annotations at all.
A background is page content drawn before everything else, so text sits on top of it. It prints as reliably as the text does, and removing it means editing the page rather than deleting an object.
So: a comment is a stamp, and a letterhead is a background. Marking a document VOID is a judgement call — as an annotation it can be removed by the recipient, which for VOID is usually the wrong property.
Making a stamp that prints
The most common complaint about stamps is that they vanish on paper. That is annotation printing being off, and it is off by default in several readers.
- Check the print dialog for "Comments and Forms" — set it to "Document and Markups" rather than "Document".
- Or flatten before sending, which merges the stamp into the page so the setting stops mattering.
- Flattening is irreversible, so keep an unflattened copy. The reasoning is in how to annotate a PDF.
If the stamp is the point of the document — an approval, a receipt mark, a certification — flatten it. A mark the recipient can drag off is not much of a mark.
Transparency
A stamp saved as JPEG arrives inside a white rectangle, which sits over the text it was meant to sit beside. This is the single most common reason a stamp looks wrong.
JPEG has no alpha channel. PNG does. A stamp, a signature or a logo intended to overlay a page must be PNG — or SVG if the tool accepts it, which also scales cleanly.
If you only have a JPEG of a stamp, the Background Remover will lift it off its white ground, and the Image Converter saves the result as PNG with the transparency intact.
Backgrounds and printing
A background image is the usual way to apply a letterhead or a branded frame to a document that did not have one.
Two things go wrong at print time. Content within about 5 mm of the sheet edge is not printed at all, because no consumer printer reaches it — so a full-bleed background arrives with a white border. And a heavy background costs ink and can make text harder to read, particularly at the margins where a gradient darkens.
Keep anything meaningful 10 mm inside the trim, and test-print a page before committing to a run. The unprintable margin catches designed documents constantly, and is covered further in why your PDF will not print properly.
What it does to file size
A text stamp costs a few drawing instructions per page — effectively nothing.
An image stamp is stored once and referenced wherever it appears, so a logo on every page adds its size once. A full-page background image is different: it is a page-sized image, and on a 40-page document that is 40 references to a large object, or in some tools 40 copies.
A "text document" that weighs 40 MB very often has a full-page background behind every page — the diagnosis is in why is my PDF so big. A letterhead drawn with vector shapes and real text costs kilobytes and stays sharp at any zoom, which is why designed templates should use vector rather than a scanned image of the letterhead.
Ticks, circles and quick marks
Marking a checkbox on a form you cannot fill in, or circling a figure for someone, is annotation work rather than editing.
Every reader has a drawing tool. The tick mark specifically is usually available as a stamp in the standard stamp palette, and failing that a drawn check or the character ✓ in a text box does the job.
If the form has real fields, use them instead — the values are data rather than a drawing, and they cannot drift out of position. How to tell the difference, and why so many "fillable" forms are not, is in how to make a fillable PDF form.
Frequently asked questions
Why does my stamp not appear when printed?
Because annotation printing is off — several readers default to it. In the print dialog set "Comments and Forms" to "Document and Markups". Flattening the document before sending removes the dependency on the recipient's setting entirely.
Why does my stamp have a white box around it?
It is a JPEG, which has no transparency, so the white background travels with it. Use PNG, or SVG where supported. A background remover will lift an existing JPEG stamp off its white ground.
What is the difference between a stamp and a watermark?
Mostly intent and placement. A stamp is usually an opaque mark in one spot, layered over the page as an annotation. A watermark is faint, spans the page, and is often placed as page content so it cannot simply be deleted.
How do I add a letterhead to an existing PDF?
As a background — page content drawn beneath the text, so it prints reliably and is not removable as an object. Keep it 10mm inside the trim, since no consumer printer reaches the sheet edge, and prefer vector over a scanned image for size and sharpness.
Will a background image make my file much bigger?
A full-page background can, yes — it is a page-sized image referenced on every page, and it is the usual explanation for a text document weighing tens of megabytes. A letterhead drawn with vector shapes costs kilobytes instead.
How do I tick a checkbox on a PDF?
If it has real form fields, click it — the value is data rather than a drawing. If it is a flat page, use the stamp palette's tick or draw one with the annotation tools. Many forms that look fillable are flat pages with boxes drawn on them.