The Colour Replacement Brush Tool works by replacing the colour of pixels on the current layer with the Primary colour selected on the Colour panel.
The pixels affected by the Colour Replacement Brush are determined by the following:
The colour of the pixel under the tool when you click on your page.
Whether the pixels are within the same selection area.
The pixels are included in the painted stroke.
The tool's Tolerance settings (see below).
The following settings can be adjusted from the context toolbar:
Width—the brush (stroke) size in pixels. Type directly in the text box or drag the pop-up slider to set the value.
Opacity—how see through the brush is. Type directly in the text box or drag the pop-up slider to set the value.
Flow—how fast the brush effect is applied (1% is very slow, 100% is immediate). Type directly in the text box or drag the pop-up slider to set the value.
Hardness—how hard the edges of the brush are. The brush appears softer as the percentage decreases. Type directly in the text box or drag the pop-up slider to set the value.
More—click to display the Brushes dialog to access advanced brush settings.
Force pressure to control size—Click to control brush size with pressure if using a pressure-sensitive device. This overrides brush defaults.
Stabiliser—enables stroke stabilisation using either a Rope stabiliser or Window stabiliser mode; the former drags the stroke end by a 'rope' to smooth the stroke but lets you introduce sharp corners at increasing rope Length (radius) values by redirecting the slackened rope; the latter will smooth the stroke by averaging sampled input positions within a Window whose size is configurable.
Tolerance—sets the range of pixels affected when a pixel is clicked. For lower tolerance settings, pixels must be very close in value to the clicked pixel. For higher tolerance settings, pixel colour can vary widely from the clicked pixel.
Sample continuously—if this option is off (default), the initial click position determines the reference colour to be replaced. When selected, new reference colours are determined as the cursor moves.
Contiguous—when selected (default), only adjacent qualifying pixels under the stroke are recoloured. If this option is off, all qualifying pixels under the stroke are recoloured, even if they are non-adjacent.