Working with the channel mixer pane

The channel mixer pane controls the mixing of red, green and blue to establish the lightness of pixels in the image. The effect of this is most noticeable in the greys of an image, but impart a more subtle effect on colours also.

The pane provides three sliders labelled Red, Green and Blue. Moving a slider to the right will increase the weighting of its respective channel in determining the lightness of a pixel.

The weights assigned to the three channels must always sum to 100% (i.e. the full width of a single slider). Consequently, increasing a slider will automatically decrease the other two sliders, and decreasing a slider will automatically increase the other two sliders. The sliders may appear to become stuck if two are set to zero -- move one of the zero sliders to the right to unstick them. This is normal behaviour.

By default the following mix is used: red (29.9%), green (58.7%) and blue (11.4%).

Use the following table as a guide to the impact of the sliders:

Slider positions Impact
Red Green Blue Lightness Detail
High Low Low Reds lighter Reds high, cyans low
Low High Low Greens lighter Greens high, magentas low
Low Low High Blues lighter Blues high, yellows low
High High Low Blues darker Yellows high, blues low
High Low High Greens darker Magentas high, greens low
Low High High Reds darker Cyans high, reds low