Improve PDF Quality – What Works and What Does Not
Dark scans, faded text and soft pages can often be made much easier to read. Pixelated, low-resolution or over-compressed files are a different problem: missing detail cannot be added back. These guides explain what helps in each case.
Tools
Enhance PDF
Adjust light, contrast, sharpness and noise of scanned pages with a live preview. Pages are saved as 200 DPI images.
OCR PDF
Add a searchable text layer to scanned pages.
Compress Scanned PDF
Make large scans smaller while keeping them readable.
Guides by Problem
Good to Know
- Enhancement works on what is in the page: it can brighten, darken and sharpen, but it cannot recreate detail that was never scanned.
- Raising the DPI of a low-resolution page adds pixels, not detail. For a genuinely sharper page, scan again at 300 DPI or use the original file.
- Quality lost through strong compression cannot be restored – compress the original again with a higher level.
- Enhanced pages are saved as images, so text can no longer be selected. Run OCR afterwards if you need searchable text.
PDF Quality – Frequently Asked Questions
Can a blurry PDF be made sharp?
Slightly soft pages can be sharpened. Pages that are pixelated because of low resolution cannot – the detail is not in the file.
How do I make a faded scan readable?
Raise Contrast, lower Blacks and raise Whites in Enhance PDF. For text-only pages, the Threshold slider turns the page into pure black and white.
Does enhancement improve OCR results?
Often for grey, noisy or faint scans. Clean scans are best sent to OCR unchanged.
Is a 300 DPI version of a 72 DPI PDF better for printing?
It is larger but not sharper. Print shops need the original high-resolution file.
Is my file uploaded to a server?
No. Enhance PDF works in your browser, so the file never leaves your device.
Is it free?
Yes – no sign-up, no watermark and no limit on the number of files.