Quick Mask
Intro
A D V E R T I S E M E N T
You can think of a mask or
an alpha channel as a more visual way to represent a selection. Think back to
earlier in this lesson when you used the feather command on a selection to
create a soft vignette effect. You could use numeric values for the feathering
amount, but there was no way to see the results of the feathering until you
deleted the background.
Let's get an introduction
to Quick Mask mode by creating a vignette effect a different way. Open an image
and make an elliptical selection.
 The
Quick Mask buttons appear directly under the color palette on the toolbox. The
shortcut key for Quick Mask is Q and this acts as a toggle to turn Quick
Mask Mode on and off.
After making your
elliptical selection, tap the Q key to switch to Quick Mask mode. The
non-selected areas of the image are visible through a red screen.
The red shading indicates
the masked (or non-selected areas). Now we want to feather the selection to
create the vignette effect... but, what's this? The Select > Feather command is
disabled. No fear... instead of feathering the selection, we can use the
Gaussian Blur filter to get the same results. The difference is, we'll be able
to see those results in real time.
 Go
to Filter > Blur > Gaussian Blur.
You may need to click and
drag in the small preview area to bring the edge of your image into view.
However, if you click the preview check box, you can preview the changes in your
actual image.
Since we went into Quick
Mask mode before invoking the Gaussian Blur filter, the effects are only applied
to our mask.
 Now
drag the Radius slider up to a range between 10-20 pixels and observe the Quick
Mask.
OK the Gaussian Blur
dialog.
Tap the Q key to
exit Quick Mask mode.
Invert your selection.
Fill with white.
While this may seem like
more steps than using the feather command, it's better because you can get a
pretty good idea if your blur amount was right before making any drastic
changes. With the feathering method it may take a few tries since it's basically
guess work and you won't know if you guessed right until you fill the
background.
That was the quick intro;
there's actually a whole lot more you can do with Quick Mask. But first, let's
explore some of the Quick Mask options.
 If
you double click either of the Quick Mask buttons on the toolbox, you can change
the options.
If you prefer the colored
area to represent the selection instead of the mask you can change that here. If
the default red overlay color isn't working for your image, you can click the
color square to change it to something that works better. And finally, you can
adjust the opacity of the overlay color. Feel free to experiment with these
options on your own.
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