Free Online HDR Tone Mapping Tool — Reveal Hidden Photo Detail
Easily apply HDR tone mapping to your images with our free online tool. Using the Reinhard global tone mapping operator, it compresses the dynamic range of your image to reveal detail that was previously hidden in overexposed highlights and underexposed shadows — while preserving local contrast for a natural-looking result. Perfect for correcting high-contrast scenes, bringing back detail in blown-out skies, brightening shadow areas, or giving your photos a subtle HDR look. All processing happens in your browser for complete privacy.
Upload one or multiple images by dragging them onto the upload area or clicking to browse your files. Batch upload supported.
Each image is tone mapped automatically as it loads — no settings or adjustments needed. The results appear in the list instantly.
Download each image individually, or click Download All to save everything as a single ZIP archive. Remove any unwanted images with the delete button.
Tips for Using HDR Tone Mapping
- HDR tone mapping works best on high-contrast scenes — landscapes with bright skies and dark foregrounds, backlit subjects, or indoor scenes with bright windows.
- For subtle enhancement, tone mapping once is usually sufficient. For a more dramatic HDR look, you can download and re-upload the result for a second pass.
- Images with strong color generally respond well to tone mapping. The effect preserves color saturation while improving detail visibility across the tonal range.
Frequently Asked Questions — HDR Tone Mapping
Is the HDR tone mapping tool really free?
Yes, completely free. No registration, no hidden charges, no watermarks, and no file size limits. All processing happens locally in your browser — your images never leave your device.
How does Reinhard tone mapping work?
The Reinhard global tone mapping operator works by: 1) Normalizing pixel values to the 0-1 range. 2) Calculating the log-average luminance of the scene to determine an 'average key'. 3) Scaling each pixel's luminance by the inverse of the key, then applying the formula: output = scaled_luma / (1 + scaled_luma). This compresses bright values more aggressively than dark values, naturally bringing out detail in highlights while preserving shadow depth.
Does HDR tone mapping require any settings?
No! Our tool uses automatic key calculation based on the image's average luminance, so it works fully automatically. Simply upload your images and the tone mapping is applied instantly. This makes it perfect for batch processing multiple photos quickly.
What image formats are supported?
JPG, PNG, WebP, BMP, AVIF, GIF, TIFF, SVG, HEIC and more. The tone mapped result is saved in your original upload format, preserving compatibility.
Will HDR tone mapping make my photos look unrealistic?
Unlike aggressive multi-exposure HDR compositing, our global tone mapping operator produces natural-looking results by preserving local contrast relationships. It compresses the overall dynamic range while maintaining the relative brightness differences between neighboring pixels. The effect is typically subtle to moderate — enhancing detail without the 'overcooked HDR' look.
How is HDR tone mapping different from auto contrast?
Auto contrast linearly stretches the existing tonal range to fill 0-255. HDR tone mapping uses a non-linear curve based on the Reinhard operator that compresses the effective dynamic range, bringing highlight and shadow detail back into the visible range. Tone mapping is designed for high-contrast scenes where the existing dynamic range exceeds what can be displayed, while auto contrast is for images with narrow tonal ranges.
How large of an image can I process?
Our tool handles images up to 50 megapixels (50,000,000 pixels total). If an individual image exceeds this limit, you'll see a warning and can try a smaller version. Batch processing supports multiple images at once.