The Darken tool tones an image by decreasing the brightness of colors. The effect is increased with each successive brush stroke.
The basic tool settings are shown in the Tool Options panel above the Image Window. To display the full list of parameters, press the tool icon in the Tool Options panel, or right-click the image. 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 Darken brush.
Hardness (0-100). The degree of softness of the tool's edge. The higher the value, the sharper the tool's edges are. At values near 100%, the boundary between the darkened area and untreated area is more distinct; at lower values there is a smoother transition between these areas.
Strength (1-100). The amount the image is darkened. At a Strength value near 100% the colors are darkened near maximum.
Fill (1-100). The intensity of darken effect with a single brush stroke. If you hold the mouse button while drawing, the strokes are overlapped and the darken effect increases.
The drop-down menu Range provides three methods for darkening an image:
Shadows. Dark areas are processed more strongly than light areas.
Midtones. Dark and light areas are processed equally.
Highlights. Light areas are processed more strongly than dark areas.
Beside the above-listed settings, some additional parameters are available for this tool.
Press the Default button to set all settings to their default values.
To darken colors in a straight line, first select a starting point for the line by left-clicking over the desire point, then, while pressing Shift, move the cursor to the desired end point and release Shift. If Shift is not released, additional lines will be drawn to each point where the mouse is clicked.