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Control the brightness and exposure of your images with luminosity adjustments. Fix underexposed or overexposed photos, correct tonality issues, or create stylistic lighting effects.

Parameters

brightness
integer
Uniformly lighten or darken the image by adjusting all pixels equally.Range: -100 to 100Default: 0
gamma
integer
Adjust brightness based on each pixel’s current luminosity, affecting bright pixels more than dark pixels.Range: -100 to 100Default: 0

How it works

Bunny Optimizer provides two methods for adjusting image luminosity: Brightness: Applies a uniform adjustment to every pixel. Increases or decreases all pixel values by the same amount, which can quickly clip highlights (lose whites) when brightening or crush shadows (lose blacks) when darkening. Gamma: Applies a non-linear adjustment based on each pixel’s current luminosity. Bright pixels are affected more than dark pixels, which mimics how human vision perceives brightness. This better preserves detail in both highlights and shadows.

Usage

Brightness adjustment

Uniformly lighten or darken all pixels in the image. The adjustment affects each pixel equally regardless of its current value.
Original
https://yourzone.b-cdn.net/image.jpg?brightness=0
brightness=0brightness=15brightness=-15
Original brightnessBrightened imageDarkened image
Positive values lighten the image, while negative values darken it. Useful for quick exposure corrections, though extreme values may lose detail in highlights or shadows.
Lighten significantly
https://yourzone.b-cdn.net/image.jpg?brightness=30
brightness=0brightness=30
Original brightnessSignificantly brightened
Darken significantly
https://yourzone.b-cdn.net/image.jpg?brightness=-30
brightness=0brightness=-30
Original brightnessSignificantly darkened
Brightness adjustments affect all pixels uniformly. High positive values can cause bright areas to lose detail (blown highlights), while high negative values can cause dark areas to lose detail (crushed blacks).

Gamma correction

Adjust brightness based on luminosity values, affecting bright pixels more than dark ones. This creates more natural-looking adjustments that preserve detail in both highlights and shadows.
Original
https://yourzone.b-cdn.net/image.jpg?gamma=0
gamma=0gamma=20gamma=-20
Original gammaGamma increasedGamma decreased
Positive values brighten the image while better preserving shadow detail. Negative values darken while maintaining highlight detail. Ideal for fixing global tonality issues or exposing additional detail in challenging lighting conditions.
Brighten with gamma
https://yourzone.b-cdn.net/image.jpg?gamma=40
gamma=0gamma=40
Original gammaHigher gamma
Darken with gamma
https://yourzone.b-cdn.net/image.jpg?gamma=-40
gamma=0gamma=-40
Original gammaLower gamma
Perfect for correcting images shot in challenging lighting, fixing tonality issues, or creating more nuanced exposure adjustments than brightness alone.

Brightness vs Gamma

The key difference lies in how each adjustment affects pixels: Brightness adds or subtracts the same value from all pixels. A brightness of +20 adds 20 to every pixel value, whether it’s already bright or dark. This can quickly clip highlights or shadows. Gamma adjusts pixels proportionally based on their current luminosity. Bright pixels receive larger adjustments than dark pixels, creating a curve that mimics human vision and preserves more detail across the tonal range. Use brightness for simple, uniform adjustments. Use gamma when you need to preserve detail in highlights and shadows, or when correcting tonality issues in photos with varied lighting.

Combining with other transformations

Luminosity adjustments work seamlessly with other Bunny Optimizer parameters:
Brighten and increase saturation
https://yourzone.b-cdn.net/image.jpg?gamma=15&saturation=10
Darken and sharpen
https://yourzone.b-cdn.net/image.jpg?brightness=-10&sharpen=5
Gamma correction with contrast
https://yourzone.b-cdn.net/image.jpg?gamma=20&contrast=5