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Adjust PDF contrast and colors
Visually adjust PDF contrast, brightness and saturation, or convert its pages to grayscale, entirely locally.
- 100% local
- Instant
- Free
- No account
- Works offline
Your files are processed locally in your browser and are never sent to our servers.
Drop your file here
Recommended size: up to 100 MB
Processing…0 %
Why use this tool?
Improve the readability of a faded scan, boost contrast, correct brightness, change saturation or create a grayscale version. Processing stays entirely in your browser.
Smart processing
Process PDF documents easily with operations suited to their structure.
Supported formats
Imported PDF files and downloadable results depending on the selected operation.
Save time
Get a clean, ready-to-use result in seconds without installing software or configuring a complex workflow.
Fonctionnement
How does this tool work?
The engine renders each page as an image, applies pixel-level corrections, then rebuilds a PDF from the corrected pages. This ensures that visual changes also apply to scans and complex content, but it rasterizes pages: vector or selectable text may therefore no longer be selectable in the output file.
Use cases
Improve a faded scan
Increase contrast to make a scanned document easier to read.
Prepare for printing
Convert a document to grayscale or adjust its brightness.
Make pages consistent
Apply the same visual corrections to an entire PDF.
Guide
How to use this tool
- 1
1. Import the PDF
Select the document to process in your browser.
- 2
2. Adjust the options
Choose the settings that match your needs.
- 3
3. Start processing
The engine processes the file locally and then provides the result.
Tips and best practices
- A contrast setting of +20% is a good starting point for a slightly faded scan.
- The transformation rasterizes pages; keep the original if you need selectable text.
- Higher quality improves rendering but increases the final PDF size.
Frequently asked questions
Is the file sent to a server?
No. Processing takes place locally in your browser and your file never leaves your device.
Is the original file modified?
No. Bethemesh generates a new result and keeps your original file unchanged.
Can this operation be used in Workspace / Pipeline?
Yes. The logic is exposed through a shared PDF transformation that can be reused in Workspace.
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