PDF Shadow Remover
Flatten the uneven lighting from phone-photographed pages, book spines, and folded documents.
Why Photographed Pages End Up With Uneven Lighting
A flatbed scanner lights a page evenly from edge to edge, but a phone camera rarely does. Point a phone at an open book and the spine curves away from the light, darkening toward the center fold. Photograph a single sheet on a desk and one corner often falls into shadow from whatever’s blocking the light overhead. The result is a page where the text near one edge is perfectly readable and the text near the other edge is barely visible. A flat, single-number background cleanup can’t fix this, because the darkness isn’t uniform — it’s a gradient. PDF Shadow Remover is built specifically to read and correct that gradient rather than apply one blanket setting to the whole page.
How Directional Correction Works
Instead of treating every pixel the same way, this tool scans across the page in the direction the shadow falls, measuring how brightness shifts from one edge to the other. It then builds a correction that lightens the darker side proportionally more than the brighter side, evening the page out instead of just raising overall brightness. Auto-Detect analyzes the page and picks the most likely direction; you can also set it manually if you know exactly how the shadow falls, such as a book spine running down the vertical center.
Auto-Detect Direction
Reads brightness patterns across the page and automatically identifies whether the shadow runs top-to-bottom, side-to-side, or from a corner.
Manual Direction Override
Know exactly where the shadow falls? Lock in the direction yourself for more precise, predictable results.
Adjustable Intensity
Control how aggressively the gradient gets flattened, from a light touch to a strong correction for deep shadows.
Combined Background Flatten
Optionally run a general background cleanup pass afterward to catch any remaining tint once the shadow itself is corrected.
Typical Situations This Solves
- Photos of open books or bound documents where the spine casts a shadow down the middle
- Pages photographed under a desk lamp or overhead light, darker on one side
- Folded or creased pages photographed flat, where the crease shadow follows the fold line
- Documents shot near a window, with natural light brighter on one edge than the other
How to Use It
- Add your file: Upload the photographed or scanned PDF with uneven lighting.
- Pick a direction: Leave Auto-Detect on, or choose the direction manually if you know it.
- Set intensity: Adjust how strongly the gradient should be flattened.
- Correct and download: Get your evened-out page in seconds.
Runs Locally, Every Time
All shadow analysis and correction happens directly in your browser. Nothing about your document — its content, its images, or the file itself — is ever sent to an external server.
Frequently Asked Questions
What’s the difference between this and a regular background cleaner? A regular cleaner applies one setting to the whole page. This tool reads how brightness changes across the page and corrects that gradient specifically, which works better on directional shadows.
What if my shadow doesn’t match any of the direction options? Auto-Detect usually handles irregular shadows reasonably well; for complex lighting, try Corner/Spine mode, which blends both directions.
Can this fix a shadow cast by my own hand or the camera itself while photographing? Mild shadows from this are usually correctable; very dark, sharp-edged shadows may still leave a faint trace after correction.