Removing redeye used to be a major requirement for digital photographers, but these days newer sophisticated cameras can minimise it when you take the picture. But for those of you who want to have a go, here's a Redeye removal technique, using Channels - another aspect of digital images.
For this task, we'll use the picture of two young children.
First of all open the 'twokids' image.
Next, as with the cloning task, you should zoom in on the image to help you work with the detail.
Zoom in on the girl's face as shown, using the zoom tool.
Then, in the Layers palette, select the Channels view using the icon highlighted by the red square.
Channels are a useful feature of all digital images. Images are produced by combining pixel layers of red green and blue pixels. With most digital imaging programs you can work with the individual pixel layers.
Step 2 - Select the eye pupil 
This is done by choosing the Elipse selection tool (arrowed) and making sure that the tool is set to Feather, with a radius of around 2 pixels (highlighted by the red box). This will give the selection a 'soft' edge.
Make sure all the channels are visible. Now you are ready try some removal. Bring up the Channel Mixer by using the menu command: FILTER > COLORS > CHANNEL MIXER.
In the mixer try these settings:
Red: 10
Green: 60
Blue: 30
Then click OK to apply and zoom out of the image to check the result agains the unretouched eyes.
If you want to apply the colour change to all the eye pupils at once, you will need to select them first.
To do this you should make sure you click on the 'Add to current selection' button next to the Mode: option in the elliptical selection tool options palette (right):