What is the difference between overlay and underlay?

Overlay draws the layer PDF on top of the base pages, like a stamp or watermark. Underlay places it behind the base content, like letterhead or a background form.

Which file is the base and which is the layer?

The base document keeps its pages and page count. The layer PDF supplies the pages that are composited onto or behind the targeted base pages.

Can I apply the layer to only some pages?

Yes. Leave the page field blank for every page, or use ranges like 1-5, comma lists like 2,4,8, and the odd or even shortcuts.

What happens if the layer PDF has fewer pages than the base?

By default the layer is used in order until it runs out. Turn on looping to repeat a short layer across every targeted page, so a one-page letterhead can cover the whole document.

Can I preview the result before downloading?

Yes. Once both PDFs are loaded, the preview lets you move through base pages, zoom, and see whether each page gets a layer page, stays untouched, or receives it above or below.

Does it change the base PDF's page count?

No. The output keeps the base document's pages. The layer is composited onto the targeted pages rather than inserted as new pages.

Can I use password-protected PDFs?

Yes. Protected base or layer files show an unlock card in the workspace. Unlock them locally or cancel before applying the layer.

Are my PDFs uploaded to a server?

No. Both documents are read and composited locally in your browser. Nothing leaves your device.

تركيب PDF: ترويسة وأختام وخلفيات فوق الصفحات

ضع ملف PDF فوق آخر أو خلفه، وحدد الصفحات المستهدفة، وكرر الطبقات القصيرة، ثم عاين النتيجة ونزّلها بخصوصية داخل متصفحك بسهولة.

1. Add base and layer

Choose the PDF that keeps its pages, then the letterhead, stamp, or background to apply.

2. Set placement

Pick overlay or underlay, target pages with ranges, odd/even, or lists, and loop short layers.

3. Download

Preview which pages are touched, then save the composited PDF locally.

About Overlay PDF

Put One PDF On Top Of Another

Some PDF jobs are really two documents: the pages you want to keep, and the thing you want printed on them. A letterhead behind a contract. A confidential stamp across a report. A background form under a scan. Overlay PDF composites a layer document with a base document so the result is one clean PDF.

Load the base document first, then load the layer PDF. Choose whether the layer prints on top as an overlay or sits behind the content as an underlay, then target exactly the pages that need it.

What You Can Control

The settings are small on purpose: placement, target pages, and what happens when the layer is shorter than the base.

Overlay Or Underlay

Draw the layer above the base pages for stamps and marks, or behind them for letterhead and backgrounds.

Page Targeting

Apply to every page, odd or even pages, ranges like 1-5, or comma lists like 2,4,8.

Loop Short Layers

Cycle a one-page letterhead across every targeted page instead of stopping after the first layer page.

Page Preview

Step through the base pages and see which layer page lands on each one before you download.

Made For Letterhead, Stamps, And Forms

Add a company letterhead behind a plain export, put a draft or confidential mark over every page, or place a form template under a filled scan. Page targeting means the cover can stay clean while the layer hits only the pages that need it.

When the layer has fewer pages than the target range, looping repeats it in order. A single-page background can cover a hundred-page document without turning the layer into a hundred-page file first.

How It Compares

Merging puts pages next to each other. Overlay puts them on the same page.

الميزة	Merge tools	Basic stamp tools
Layer above or below content		Top only
Ranges, lists, odd and even targeting		Varies
Loop a short layer across pages
Preview page-by-page mapping		Varies
Password-protected input handling	Varies	Varies
No file upload required

Private Compositing In The Browser

Letterhead and stamp jobs often involve contracts, HR paperwork, invoices, or scans that should not be sent to a random server. OxygenPDF reads both PDFs locally, composites them in your browser, and never uploads either file.

If a file is password-protected, unlock it inline before processing. Close the tab and the documents are gone.