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VellumPDF

Enhance a scan

An unreadable scanned document comes out clean, ready to read or OCR.

Your files never leave your device

Drop a PDF or an image here

Scanned PDF or photo — JPG, PNG, WEBP

How to enhance a scanned PDF, step by step

A dull or greyish scan gets cleaned up with three combinable settings, with the result visible before it is generated.

  1. Drop in a scanned PDF or a photo

    JPG, PNG and WEBP are accepted alongside PDF. A Before/After preview is computed right away, on a downsized version to keep it fast.

  2. Choose the rendering

    Color, Grayscale or Black & white.

  3. Set the intensity

    Light, Normal or Strong drive how much the background is whitened and how much contrast is applied to the text.

  4. Leave sharpness on, or turn it off

    On by default, it slightly enhances the text edges.

  5. Click “Enhance and generate PDF”

    Every page is reprocessed at full resolution, then rebuilt as JPEG in a new document.

The resulting file is an image PDF: the text is not selectable, and this tool does not straighten crooked pages. For searchable text, run OCR; for orientation, use the Straighten tool.

Frequently asked questions

What rendering modes does VellumPDF’s scan enhancer offer?

Three renderings are available: revived colour, cleaned-up grayscale, or black and white via an automatic threshold. A before/after preview lets you fine-tune the result before generating the final PDF.

Does the enhanced PDF keep its text selectable?

No, the document produced is made of images: the text is no longer selectable or searchable. Optical character recognition (OCR) is needed afterwards if you need to search or copy the text.

Does this tool work without sending the scan online?

Yes, all processing happens in your browser, with no page ever sent to a server. The tool is free, and a password-protected PDF must be unlocked first.

Which renderings and strengths are offered?

Three renderings — colour, grey, black and white — and three strengths: light, normal, strong. Black and white at strong gives the most readable and lightest page for photocopied text; colour at light suits a document where colour carries information, a chart or a highlight.

How do I choose without trial and error?

By looking at the page before and after: the preview puts the two side by side. A strong setting on an already clean scan over-deepens the contrast and can erase a pencil stroke; a light setting on a grey, veiled scan will not be enough. Two attempts show the right value.

Is the improved document still a real PDF?

Yes, with its pages, their order and the original page size. The pages are reprocessed as images, though: if your scan already carried a text layer from character recognition, run it through recognition again after enhancement so it becomes searchable once more.