After one too many "wouldn't it be nice if there was a tool that just did this" moments while staring at single-page PDFs that needed to look like an actual open book — I tried building one.

[**Spread that sheet**](https://spread-that-sheet.org) takes a PDF where each page is a single leaf and pairs them into double-page spreads — simulating how they'd look in a physical open book.

You can fine-tune:

* **Gutter shadow** — adjustable intensity and width
* **Page curvature** — pages compress near the spine like a real binding
* **Page margins** — visible page edges that darken gradually
* **Paper texture** — built-in textures or upload your own
* **Transparency** — reverse-side bleed-through for thin paper simulation
* **Cover board** — hardcover expansion with adjustable darkness
* **Canvas wrapper** — custom background for presentation-ready output
* **Multiple PDFs** — combine cover + interior files with auto page mapping

The result looks very close to what you'd get scanning an open book on a flatbed scanner.

There are probably too many options — I'll admit I got a bit carried away — but if you ever get lost, just hit the **?** button to bring up the interactive guide at any time.

Export as PDF, PNG, or JPG at full 300 DPI. Everything runs locally in your browser — nothing gets uploaded anywhere.

Would love to hear your feedback: [spread-that-sheet.org](https://spread-that-sheet.org)

I built a free browser tool that turns single-page PDFs into realistic book spreads — no install, no sign-up