How to remove shadows from scanned documents

The most common flaw in phone scans is a grey shadow across the page — from your hand, your head or the phone itself. Here's how to prevent it and how to remove it when it's already there.

Why shadows happen

When you lean over a page, you block the light source behind you. The camera sees one half of the paper brighter than the other. Ceiling lights directly above make it worse, because the phone sits right between the lamp and the paper.

Prevent shadows while scanning

• Put the light in front of you or to the side. Turn so the window or lamp faces you.
• Raise the phone a little. A higher position casts a smaller, softer shadow.
• Use daylight instead of a single strong lamp.
• Avoid the flash. It replaces a shadow with a glare spot.

Remove shadows automatically

Osd-Scan applies shadow removal to every page by default:

1. Scan or import the page in Scan to PDF.
2. The Auto color filter evens out the background, makes the paper white and keeps ink, stamps and signatures.
3. For grayscale output, choose Grayscale — the same cleanup without color.

Fine-tune a stubborn page

Open the page and go to Adjust:

• Shadow removal — increase it for strong, soft shadows.
• Clean background — whitens the paper and removes faint marks, creases and see-through text from the back side.
• Contrast — makes text stand out after cleanup.
• Brightness — lift a page that still looks dark.

When to retake the photo

If the shadow covers text with very low contrast — for example pencil in a dark corner — no software can fully recover it. Retaking the photo with better light takes ten seconds and gives a perfect result.

Bonus: see-through text

Thin paper often shows text from the back side. Clean background reduces this ghosting too. For double-sided printouts, it's often the single most useful slider.

A clean, evenly lit page reads better on screen, prints without grey bands and compresses to a smaller file. Two habits — light in front, auto cleanup on — are all it takes.