The Saturation tool tones an image by changing the saturation and contrast of neighboring pixels.
The basic tool settings are shown in the Tool Options panel above the Image Window or by right-clicking on the image. To display the full list of parameters, press the tool icon in the Tool Options panel or use the F5 key. To specify the parameter settings, enter a numerical value in the parameter’s field or use the slider.
Element - in the drop-down list, select the type of the basic element of the brush: Ellipse or Select Shape.
Size (1-5000). Size of the Saturation tool.
Hardness (0-100). The softness of the tool’s edge, where the effect is applied partially. At higher values the boundary between treated and untreated areas is more distinct; at lower values the transition between these areas is processed more smoothly.
Strength (1-100). The strength of the effect. The higher the value, the stronger the change.
Fill (1-100). The intensity of the effect in a single brush stroke. If you hold the mouse button while drawing, the strokes are overlapped and the saturation/desaturation effect increases.
The tool works in two modes: in Saturate mode colors become more saturated, in Desaturate mode colors become less saturated.
In addition to the above-mentioned parameters, you can adjust the advanced settings that affect the shape and position of the brush marks.
Press the Default button to set all settings to their default values.
To change saturation in a straight line, pick a starting point by left-clicking the mouse, then, while pressing Shift, move the cursor to the desired end point and release Shift. If Shift is not released, then a new line will be drawn to each point where the mouse is clicked.