Image Gamma

What is gamma correction?

Gamma correction is a non-linear operation that adjusts the brightness of an image using a power-law function. Unlike a simple brightness shift that adds or subtracts a constant from every pixel, gamma applies an exponential curve that affects midtones far more than the extremes. A gamma value below 1 brightens the image (lifting shadows), while a value above 1 darkens it (compressing highlights). Gamma correction is fundamental in photography, display calibration and image processing.

This tool runs entirely in your browser. When you upload an image, it is decoded through the Canvas API. As you drag the gamma slider, the tool reads the raw pixel buffer and applies the formula output = 255 × (input/255)^(1/gamma) to each red, green and blue channel. The preview updates instantly, and the result can be downloaded as a PNG file. Nothing is ever uploaded to a server.

How gamma affects images

The gamma curve is steepest in the midtone range, which is why gamma adjustment is so effective for fixing underexposed or overexposed photos. A gamma of 0.5 roughly doubles the brightness of midtones while leaving pure black and pure white unchanged. A gamma of 2.2 halves midtone brightness, mimicking the inverse of the sRGB encoding curve. This non-linear behaviour preserves detail in shadows and highlights where a linear brightness change would cause clipping.

When to use gamma adjustment

Gamma adjustment is useful in photography, design and technical imaging. Common use cases include:

Gamma vs brightness

Gamma adjustment is useful in photography, design and technical imaging. Common use cases include:

• Exposure correction. Rescue underexposed photos by lowering gamma, or tame overexposed shots by raising it.
• Shadow detail recovery. Lift dark regions without blowing out highlights, revealing detail that linear brightness would destroy.
• Display calibration. Match an image to a specific display gamma (typically 2.2 for sRGB monitors).
• Artistic mood. Create moody, dark atmospheres with high gamma, or bright, airy looks with low gamma.
• Pre-processing for vision tasks. Normalise lighting conditions before edge detection or thresholding.

Whenever you need to adjust image brightness in a way that preserves shadow and highlight detail, gamma correction is the right tool.

How to adjust gamma

Adjusting gamma with this tool takes only a few seconds and runs entirely in your browser — no uploads, no sign-up, no watermark. Follow these steps:

1. Upload your image. Click the upload area or drag and drop a JPG, PNG, WebP, GIF or BMP file.
2. Adjust the gamma. Drag the slider from 0.1 to 3.0. Values below 1 brighten, values above 1 darken. The preview updates in real time.
3. Download the result. Click "Download Gamma Image" to save the gamma-corrected PNG.

Because every step runs locally through JavaScript, your image is never sent to a server. This makes the tool completely private and fast.