BYTETOOLS

Gamma Correction

Apply gamma correction to any image online. Brighten shadows or deepen midtones with the standard power-law curve and compare before and after live.

Drop an image for gamma correctionProcessed locally — never uploaded

What is the Gamma Correction?

Gamma correction adjusts the midtones of an image with the standard power-law curve: output = 255 × (input ÷ 255)^(1/γ).

  • Standard power-law gamma curve (γ from 0.2 to 3.0)
  • Precomputed 256-entry lookup table, applied per pixel
  • Side-by-side before/after comparison
  • Black and white points stay fixed — only midtones move
  • Lossless PNG export
  • 100% private, in-browser processing

How to use the Gamma Correction

  1. 1

    Upload the image you want to correct.

  2. 2

    Drag the gamma slider — above 1.0 brightens midtones, below 1.0 darkens them.

  3. 3

    Compare the original and corrected versions side by side.

  4. 4

    Download the corrected image as a PNG.

About the Gamma Correction

Gamma correction adjusts the midtones of an image with the standard power-law curve: output = 255 × (input ÷ 255)^(1/γ). A gamma above 1 lifts shadows and midtones without blowing out highlights; a gamma below 1 deepens them without crushing pure black. It is the correct way to fix photos that look too dark or washed out, because black and white points stay anchored.

This tool builds a 256-entry lookup table from your chosen gamma and maps every pixel through it, exactly as image editors and display pipelines do. A side-by-side before/after preview makes it easy to judge the change, and the slider is debounced so even large photos stay responsive.

Processing is 100% local in your browser — the image is never uploaded to a server, and the corrected result downloads as a lossless PNG.

Frequently asked questions

What is gamma correction?

Gamma correction remaps pixel brightness through a power curve, output = 255 × (input/255)^(1/γ). Because 0 stays 0 and 255 stays 255, it changes how bright the midtones look without moving the black or white points — which is why it is preferred over simple brightness for fixing dark images.

Should I increase or decrease gamma to brighten a dark photo?

Increase it. With γ above 1 the curve bows upward, so midtones and shadows get brighter while highlights barely move. For example at γ = 2.2 a middle-grey value of 128 maps to about 186.

What is the difference between gamma and brightness?

Brightness adds the same offset to every pixel, which lifts blacks to grey and can clip highlights. Gamma applies a curve that leaves the extremes untouched and concentrates the change in the midtones, usually producing a far more natural result.

Why is 2.2 a famous gamma value?

Displays following the sRGB standard encode images with an effective gamma of roughly 2.2, a convention inherited from CRT monitors. Applying or removing that curve is how images move between linear light and what your monitor expects.

Does gamma correction lose information?

Mapping 256 input levels through a curve merges some neighbouring levels, so extreme corrections can cause slight banding in smooth gradients. Moderate adjustments are visually lossless, and the output is saved as PNG so no compression is added on top.

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