Splitting images into their channels is a useful way to edit designs before printing. Under-colour removal and tonal adjustments can be made to individual channels once they are split from the image. Image channels can also be converted into spot colour layers by renaming and recolouring them.
- Activate the image in the Layers Palette.
- Go to Layer Menu > Duplicate or click on the Duplicate button in the Layers Palette, in order to keep a copy of the image after it has been split into its layers.
- Make one of the images active and choose Separate Menu > RGB to Layers. The active image will be split into three individual layers.
- Activate the three new layers and go to Edit Menu > Invert.
- Rename the layers in the Layers Palette. Doing this will convert them to spot layers.
- Recolour the layers if necessary.
- View each layer individually with reference to the original image to see if they are suitable to use in a separation. The Split Views feature is a good way of viewing the separation against the original artwork. Or you can tile the layers out in the Layout Window using the Tile feature.
- Use the Gamma Window to adjust the tones on the layers if necessary and remove any of the layers which are not needed.
Note: If a layer has a profile set on it, then splitting it into individual layers using the RGB to Layers command sets the colours of the individual layers by extracting the relevant colour from the profile. This is useful since you would expect that the ‘red’ channel for instance should make a red looking layer. This makes it easier to identify the layers as they have the appropriate layer colour.
You can however hold down⌥ (option key) on the keyboard if you do not want this to happen, which changes the menu item to ‘RGB to original Layers’. Doing this restores the original layer attributes (such as colour, transparency etc.) rather than using the profile. The file must be in .ava4 format to do this though.