Colorize Channel converts the image to gray scale and then maps the gray values to the selected colors.

Tints.

Converts the image to gray scale using the red channel.

Converts the image to gray scale using the green channel.

Converts the image to gray scale using the blue channel.

Converts the image to gray scale using the alpha channel.

Converts the image to gray scale using the luminance of the image.

Determines whether or not the color contributes to the gradient.

Picks the color that the image will be colorized with. Select the desired color using the color picker.

Determines where the colorization is applied to the image. By default, Shadows are set to 0, which is the shadow areas. A value of 50 would be the midtones, while 100 would be highlights.

The Midtones controls are the same as the controls for the Shadows, except by default, the colorization is applied to the midtones of the image.

The Highlights controls are the same as the controls for the Shadows, except by default, the colorization is applied to the highlights of the image.

You can optionally use a gradient that limits where the node is applied. Grad is the transition area that goes from the colorized image to the original image. Its direction, corners and size can be adjusted. Go to the Grad section of Common Node Controls to see how the Grad controls work.