Are my documents uploaded anywhere?

No. Every step — decoding the photo, the image processing, and building the PDF — happens entirely inside your browser using JavaScript and the Canvas API. No file ever leaves your device, which is why this works offline once the page has loaded and is safe for sensitive paperwork like contracts, IDs and bank statements.

What is the difference between Magic colour and Black & white?

Magic colour estimates the page background per region and divides it out, which flattens uneven lighting and shadows so the paper turns bright white while ink and colour stamps stay readable. Black & white converts each pixel to pure black or white using an adaptive threshold — the smallest possible file, ideal for plain text documents you want to print or fax.

How does it remove shadows and uneven lighting?

The scanner samples the brightest luminance across a coarse 24×24 grid to estimate where the white paper is, then smoothly upscales that map and normalises every pixel against its local background. Areas that were dimmed by a shadow get lifted back toward white, so a photo taken in imperfect light still looks like a flat-bed scan.

Can I scan a multi-page document?

Yes. Add as many photos as you like — each becomes a page. You can reorder pages by dragging the thumbnails, move them up or down, delete bad shots, and then export everything as a single multi-page PDF in the right order.

What file format should my photos be?

JPG and PNG work everywhere. Photos straight from a phone are usually JPG and decode instantly. If your phone saves HEIC, export or share the photo as JPG first (most phones do this automatically when you share), then drop it in here.

How do I get the cleanest result?

Fill the camera frame with the page, shoot in even light without harsh shadows, and keep the paper flat. Then use Magic colour or Black & white, nudge contrast up, and leave Sharpen text on. The threshold slider in Black & white mode lets you control exactly how aggressively faint marks are kept or dropped.

Why are black & white pages exported losslessly but colour pages as JPEG?

A pure black-and-white page compresses perfectly as PNG with no artefacts and a tiny file size. Colour and greyscale pages contain smooth gradients that PNG cannot compress well, so they are saved as JPEG at your chosen quality to keep the PDF small while still looking sharp.

Document Scanner — Gera Tools

A browser-based document scanner that turns ordinary phone photos of paper into clean, high-contrast scanned pages and exports them as a single multi-page PDF. It is for anyone who needs to digitise a contract, receipt, form, ID, or handwritten note without installing an app or trusting a website with sensitive paperwork — because every pixel is processed locally and nothing is ever uploaded.

Most photos of documents come out dim, shadowed and slightly skewed. This tool fixes all three: it flattens uneven lighting, boosts contrast so ink reads crisply, and lets you rotate each page to upright. The result looks like it came off a flat-bed scanner, not a kitchen table.

How it works

Drop one or more photos and each becomes a page. For every page you choose a scan mode:

Magic colour estimates the page background and divides it out, whitening the paper while keeping ink and coloured stamps. This is the everyday default.
Black & white applies an adaptive threshold: instead of one global cutoff, each pixel is compared to the brightness of the paper around it, so faint text survives and shadows do not turn into black blobs. It produces the smallest files.
Greyscale keeps soft tones, which suits photos of printed images or pencil notes.
Colour simply tidies brightness and contrast on the full-colour original.

Behind the scenes the image runs through a pixel pipeline on an HTML canvas: brightness and contrast are applied with a standard contrast-factor formula, the background-normalisation step removes uneven lighting, and an optional 3×3 sharpen convolution crisps up text edges. Sliders update the preview live. When you export, each processed page is drawn onto an A4, US Letter, Legal, or fit-to-image PDF page using jsPDF, centred inside your chosen margin, and the whole document is saved with one click.

Example

You photograph a three-page rental agreement on a desk under a window. The bottom of each shot is darker than the top, and the paper looks grey. You drop all three photos in, pick Magic colour, and the shadow gradient disappears — the pages turn uniformly white. You nudge contrast to +35 so the signatures stand out, rotate the second page that came in sideways, drag the thumbnails into the right order, choose A4 with a 24pt margin, and click Download PDF. You get a tidy three-page scan-2026-05-30.pdf that looks professionally scanned — and not a single byte left your laptop.

Mode	Best for	Output in PDF
Magic colour	Everyday documents, mixed ink/colour	JPEG
Black & white	Plain text, printing, faxing	PNG (lossless)
Greyscale	Photos of printed pages, pencil notes	JPEG
Colour	Receipts, anything where colour matters	JPEG

Every figure, photo and page stays in your browser — there is no server, no account, and no upload.