If you have flat areas of colour or masks on an 8 bit layer, you can convert them to tone by using the Retone options.
Retone copies the tonal range from the image using the shape of an existing mask and puts the tone on the active layer. It works best when used in conjunction with Automatic Tonal Separations.
Note: You can retone several layers at one time.
Retone
This method assumes that black is always the most saturated colour possible, and applies tones to mask layers in relation to this theory.
- Follow the Automatic Tonal Separation method (for creating continuous tone layers) to create flat masks for each colour in the separation. Alternatively, draw a solid shape on your layer by hand to mask the area.
- Make sure your mask layers are 8 bit depth and make them active but invisible in the Layers Palette.
- Make the image visible, but not active.
- Go to Separate Menu > Retone.
- The flat areas of colour on the layers will change and become smooth, continuous tones and will look similar to the original image.
If the resulting tones on your layers do not look similar enough to the original, try using the Gamma Window to adjust them. Also, it may help to adjust the colour of your layers slightly to get them looking closer to the original image.
Retone Spot
This method separates the colour of the active layer as if that colour was the most saturated colour in the design.
The picture above compares the original image (left) with a layer created with Retone (in the middle) and a layer created with Retone Spot (on the right). The same layer colour was used in each case but the tonal values of the two results are different – particularly in the lower tone areas in this example.
Hold down ⌥ (option key) and choose Separate Menu > Retone Spot to separate any masks on the active layers using the chosen layer colours as the starting point for the separated tones.