# ImgSharp — Free Online Image Sharpener

> Deterministic CIE LAB luminance image sharpener for photos, e-commerce listings, real estate interiors, scanned documents, and transparent PNG print assets. Runs 100% locally in the browser with zero image uploads, no watermarks, and full-resolution export.

## Core Capabilities

- **CIE LAB Luminance Optical Sharpening**: Sharpens the L* (lightness) channel only while keeping a* and b* chromaticity channels untouched, preventing RGB color fringes and chromatic noise.
- **Industry Presets**:
  - **General Photo**: Balanced micro-contrast recovery for portraits, travel, and smartphone photos.
  - **E-Commerce Product**: Crisp product textures with a pure-white (#FFFFFF) studio background halo guard for Amazon, Shopify, and eBay listings.
  - **Real Estate & Interior**: Architectural edge clarity with flat-wall and sky ISO noise suppression for MLS property photos.
  - **Scanned Document & Text**: High-contrast character edge definition and paper shadow lift for invoices, receipts, and PDF scans.
  - **Transparent Sticker & Print**: Alpha-boundary-safe sharpening plus optional 300 DPI PNG pHYs metadata injection for print-on-demand workflows.
- **Format & Batch Support**: Accepts JPG, PNG, WebP, and iPhone HEIC/HEIF up to 50 MB per image; batch-processes up to 10 images with one-click ZIP export.
- **Privacy Guarantee**: Local Optical Mode processes pixel buffers inside an in-browser Web Worker. Photos are never uploaded to external servers.

## Key URLs

- [Free Online Image Sharpener Workspace](https://imgsharp.com/): Main interactive image sharpener, before/after split slider, 200% optical loupe, and batch ZIP exporter.
- [Pricing & Pro Roadmap](https://imgsharp.com/pricing): Forever-free local optical sharpener details and upcoming cloud batch API tiers.
- [About ImgSharp](https://imgsharp.com/about): Optical engineering methodology and privacy architecture.
- [Privacy Policy](https://imgsharp.com/privacy): Local browser processing and zero-upload data handling commitments.
- [Terms of Service](https://imgsharp.com/terms): Usage terms and full user copyright retention.