Secure your PDF with strong password protection and encryption.
Reduce file size without losing quality.
Washed‑out scans make text hard to read, print poorly, and confuse OCR engines. Our AI‑powered contrast enhancement intelligently darkens faded text, whitens yellowed backgrounds, and normalises uneven lighting – all without losing fine detail. Perfect for old documents, low‑quality scans, or any PDF where the text blends into the background. No software installation – your files are processed securely and automatically deleted.
Did you know? Studies show that optimal contrast can improve reading speed by 25% and boost OCR accuracy by over 40%. A simple contrast adjustment often transforms an unreadable scan into a perfectly clear document.
Makes text light grey and background almost white, losing the distinction.
Old paper absorbs light, reducing the difference between ink and page.
Ink fades to light brown or grey, blending with the paper.
Shadows from book spines create bright and dark regions on the same page.
Bonus issue – low DPI scanning: Low resolution (150 DPI) makes text edges soft, further reducing perceived contrast. Our contrast boost combined with upscaling gives the best result.
Upload your low‑contrast scan – Our system analyses the tonal range and brightness distribution.
Select contrast strength – Mild (light correction), Medium (recommended), or Strong (aggressive darkening).
Apply AI contrast enhancement – The tool uses adaptive histogram equalisation to darken dark areas and brighten light areas. A real‑time preview shows the transformation.
Download the high‑contrast PDF – Text will be dark black, background clean white.
Pro Tip: If your scan has uneven lighting, enable "Background normalisation" before contrast adjustment. This flattens the illumination, producing a consistent background.
Our presets combine these techniques automatically. Advanced users can adjust each parameter in the manual mode.
If your scan includes faded colour – old maps, diagrams, or handwritten notes in coloured ink – enable the "Color Boost" option. It increases saturation and vibrance while also improving contrast. Use it sparingly, as over‑saturation can look unnatural. Start with "Light" and check the preview.
Real‑world example: A historian had a 19th‑century map with faded brown lines and yellowed paper. After contrast boost + colour enhancement, the map details became clearly visible, and the background returned to near‑white.
Contrast adjustment processes only the existing pixels; it does not add or remove pixels. Therefore, file size remains virtually unchanged (often a few KB increase for metadata). You can apply any contrast strength without worrying about file size growth. For best results, apply contrast before any upscaling.
Tip: If the PDF also has noise, remove noise first, then increase contrast. Noise removal works better on low‑contrast images, and contrast enhancement after denoising gives a cleaner result.
⚡ Need to adjust or standardise DPI without changing pixels?
Use our dedicated PDF DPI Changer to view, adjust, or unify the DPI metadata of embedded images. Perfect for pre‑press compliance, print workflow validation, and preparing files for commercial printing without altering visual quality.
Low contrast happens when scan brightness is too high (washes out text) or too low (darkens background). Also, old paper, faded ink, or low‑DPI scanning contribute. Our contrast correction automatically stretches the tonal range, making text dark black and background white.
Yes. You can adjust the background whiteness level. The "Balanced" mode keeps a slight off‑white for documents with delicate paper texture; "Strong" pushes to pure white for maximum contrast.
Our tool works on grayscale and colour scans. It can darken faded coloured text (e.g., red or blue ink) as well as black. For very faded colours, use the "Color Boost" option.
Contrast changes alone add almost no file size (under 2%). The main size factor is DPI and compression. You can apply contrast enhancement without upscaling to keep the file small.
Yes. Our algorithm separates text and image regions. It applies stronger contrast to text areas to make letters pop, while preserving natural tonal range in photos.
Yes. All uploads are encrypted with TLS 1.3 and automatically deleted within 24 hours. An offline desktop version is also available.
Yes, the tool is fully responsive and works on iOS and Android. Upload from cloud storage or camera roll. Processing runs in the cloud, so your device does not need high processing power.
Upload your faded PDF and let AI restore rich, dark text and a clean white background in seconds.
Enhancing a PDF improves visual clarity by adjusting resolution, sharpening text edges, and increasing contrast between foreground and background elements. This process is particularly useful for scanned documents, blurry text, or faded paperwork.
Several factors may reduce the readability of a PDF document. Low-resolution scanning, aggressive compression, improper export settings, and camera-captured documents can all introduce blur or reduce contrast.
Modern PDF enhancement tools apply multiple processing techniques to improve readability.
PDF enhancement algorithms work by analyzing pixel density and grayscale distribution. Contrast adjustment increases the difference between text and background while sharpening filters reconstruct blurred edges. When combined with OCR preparation, enhancement dramatically improves machine readability.
Explore the full collection of tools in the PDF Enhancement Guide.