Note: The purpose of step 3 is to show how you can take things a step further, to increase your understanding about channels and masks and how they can work together to achieve your goals. However only step 1 and 2 are needed to understand non-destructive use of the red eye tool.

Notice that our Red Eyes layer is pretty much completely black. When we see something like this we should immediately think about... yes, masks.

So is there a way to use the result of Red Eyes layer as a mask? Yes, by using channels.
Let's look at the channels by clicking on the channels tab:

Notice that it's not only showing the content of our current layer (Red Eyes), but all visible layers instead. So to see only the current layer we have to make the Background layer invisible. First click on the Layers tab and then click on the eye icon in front of the Background layer, which will make this layer invisible. The return to the channels by clicking on the channels tab in your layers palette:

 

Click on every channel and notice how the red channel would be the proper candidate for a mask, which is obvious since we're attacking the red in the eyes:

 

I'm now going to show you how you can turn the content of a single channel into a mask.

First select the Red channel:

Select the content of this channel by pressing Ctrl + A (command + E on the Mac) or by choosing in the menu Select / All.
Copy the content of this selection to your clipboard by pressing Ctrl + C (command + C on the Mac) or by choosing in the menu Edit / Copy.
Remove the selection by pressing Ctrl + D (Command + D on the Mac) or by choosing in the menu Select / Deselect.

Click on the thumbnail of the RGB channel(A) to activate all channels (all will now have a in front of them).
Click on the Layers tab (B) to return to the layers palette.

 

The next step is to make the Background layer visible again by clicking inside the box marked with the arrow (A); the icon will reappear.
Now remove the Red Eyes layer by dragging/dropping it onto the Delete layer icon (B).
Continue by clicking on the Create new fill or adjustment layer icon in your layers palette (C):

 

Select Hue/Saturation...
Click on the OK button to leave the Hue/Saturation window for now.
Rename this layer to Red Eyes Correction and change the color to red (right clicking its eye icon ):

Alt + click (Option + click on the Mac) on the thumbnail of the mask (A in previous screenshot).
Right now your document window should be completely white and that's because we've opened the mask in our document window. Only this method allows us to paste content to the mask.
Now past the content of our clipboard (the content of the red channel of our old Red Eyes layer) to our mask by using the shortcut Ctrl + V (Command + V on the Mac) or by using the menu: Edit / Paste

Now open the Hue/Saturation adjustment window by double clicking on its icon in the layers palette:

 

Enter a value of -100 for Saturation and a value of -100 for lightness and click OK:

 

You'll notice that there's still some red left in the eyes after making this correction:

 

The reason is because our mask doesn't have enough contrast:

We can fix that by using tools like Levels, Curves, Brightness & Contrast, etc.
Let's use Levels for this one; click once on the thumbnail of the layer mask to make it active (it will now have a double border):

Select in the menu Image / Adjustments / Levels...
Move the white slider to the left (A) until it reads 110 in the box labeled with B or just type the value inside that box:

Click OK when you're done.
The contrast of the mask is now improved...

...and the pupils are now black:

Feel free to make a final Hue & Saturation adjustment with new settings.

Red eyes... there are many solutions to correct it and using a hue & saturation layer in combination with a mask like in our Change the color of an eye tutorial is just one of them, although it has become pretty much obsolete for those users of Photoshop CS2, since its Red Eye tool is already doing an excellent job. The advantage of the method shown in step 1-2 of the current tutorial however is that it's non-destructive, meaning that you can adjust the result or remove it completely. Non-destructive editing is all about having full control. Photoshop offers that for example with masks, adjustment layers and layer styles, but some things are more complicated and that's how tutorials like these can hopefully help. Our non-destructive editing tutorial has more examples of non-destructive editing and can help you understand its power. Don't forget that to be successful with non-destructive editing you have to change your mind set, meaning that you shouldn't always try to copy traditional methods that are part of drawing or coloring on paper, but instead you need to try to understand what it is that Photoshop can offer what traditional methods can't. I hope you enjoyed this tutorial.

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