This method allows you to adjust the brightness, contrast, and gamma value of an image.

Unlike the adjustments that can be made on the Display tab, here the pixel values of the image are changed.

Parameter

Description

Brightness

Adjusts the desired brightness with the slider or input field.

Increases or decreases the value of each pixel by a constant value up to the limits (given by the pixel type). The range of brightness values (i.e. the relative brightness of light and dark areas of the image) remains constant.

Contrast

Adjusts the desired contrast with the slider or input field.

Broadens or narrows the range of brightness values (i.e. the relative brightness of light and dark areas of the image). A high contrast helps distinguish the light and dark areas of the image. Increasing the contrast can cause subtle graduated tones to be lost, whilst decreasing the contrast can cause the image to look soft.

Gamma

Adjusts the desired gamma value with the slider or input field.

Enhances details in brighter or darker image regions. Setting the gamma value causes the value of each pixel to be multiplied by an individual factor. This factor depends on the pixel value (brightness) itself.

  • Gamma < 1:
    • Details in bright image regions reduced
    • Details in dark image regions enhanced
  • Gamma = 1: No change
  • Gamma > 1:
    • Details in bright image regions enhanced
    • Details in dark image regions reduced