Gamma is an important but seldom understood characteristic of virtually all digital imaging systems. It defines the non-linear relationship between a pixel's numerical value and its actual luminance. Without gamma, shades captured by digital devices wouldn't appear as they did to our eyes (on a standard monitor). Understanding how Gamma works can improve the image visualization and the details visibility. Our eyes do not perceive light the way the acquisition devices do. With an acquisition device, when twice the number of photons hit the sensor, it receives twice the signal (a "linear" relationship). That is not how our eyes work. Instead, we perceive twice the light as being only a fraction brighter — and increasingly so for higher light intensities (a "nonlinear" relationship).

Compared to an acquisition device, we are much more sensitive to changes in dark tones than we are to similar changes in bright tones. There is a biological reason for this peculiarity: it enables our vision to operate over a broader range of luminance. Otherwise, the typical range in brightness we encounter outdoors would be too overwhelming.

Below are some examples to clarify practically the Gamma concept:

Gamma = 1.0

A "linear" transfer function.

This is the default value.

Gamma = 2.0

A “non-linear" transfer function.

The dark part of the range is expanded.

Gamma = 0,5

A “non-linear" transfer function.

The bright part of the range is expanded.

The Gamma value can be modified dragging the gamma slider left or right or directly inputting the value into the text box.

The curve shape can be also modified.

Gamma = 1.0 - "linear".

Gamma = 0,5 - “non-linear" The bright part of the range is expanded.

Gamma = 1,98 - “non-linear" The dark part of the range is expanded.

The Color Settings parameters can be exported / Imported as file.