Auto Contrast

Optimize your photo's contrast and dynamic range in one click. The tool analyzes the image histogram, automatically stretches the light and dark distribution, and lets you clip extreme pixels to avoid blown-out highlights and crushed shadows. All processing happens locally in your browser.

🎚️

Drop a photo or click to upload

PNG, JPG, WEBP, BMP

What Is the Auto Contrast Tool?

The Auto Contrast tool uses histogram stretching to automatically optimize the light and dark distribution of an image, turning flat, hazy photos into clear ones with depth.

No need to adjust curves manually — one click gives you a fuller dynamic range.

How to Apply Auto Contrast

Follow these steps:

  • Drop or upload the photo you want to optimize.
  • Adjust the clip ratio as needed (0.5% by default).
  • Click Apply Auto Contrast and review the result.
  • Download the optimized image as a PNG file.

Tips

  • Flat, hazy photos show the biggest improvement.
  • For photos with normal contrast, set the clip ratio to 0.
  • Combine with HDR Tone Mapping for even richer detail.

Frequently Asked Questions

How does auto contrast work?+
The tool analyzes the image's brightness histogram, finds the actual darkest and brightest pixels, and stretches them across the full range (0–255), making the light and dark distribution fuller and giving the image more depth.
What does the clip ratio mean?+
The clip ratio decides how many extreme pixels are ignored. Setting it to 0.5% ignores the darkest and brightest 0.5% of pixels, preventing a few outliers (like specular highlights) from skewing the stretch.
Will it over-process my photo?+
The default 0.5% clip ratio is fairly gentle. If the image already has normal contrast, the stretch is minimal; low-contrast images see a clear improvement.
Is my photo uploaded anywhere?+
No. All processing happens locally in your browser — your photos never leave your device.

Related Tools

Histogram EqualizationWhite BalanceHDR Tone MappingImage Filters

Auto Contrast — free online auto contrast, contrast adjustment, histogram stretch, brighten photo, auto contrast photo, contrast enhancement. No signup required. Works in your browser.