Graphics Tutorials
Quick Mask Tutorial

Thurs, 26 Apr, 2007
Lee Thompson-Herbert

Using Quick Mask mode in PhotoShop to select complex-shaped objects.


This tutorial teaches you how to use PhotoShop's Quick Mask mode to quickly and easily select complex-shaped objects either for clipping or for moving onto their own layers. This method is often quicker and more accurate than using the Background Eraser tool or the Extract filter. And it's far easier than trying to make the Magnetic Lasso actually follow the shape you want, rather than pixel variations that aren't obvious to the eye but fool the program.

I'm starting out with a pretty easy extraction, it's just the object on a white background. However, the reflections on the pen nib will almost certainly cause the Extract filter to delete portions that I want to keep. Therefore, Quick Mode is probably a better method here.

At the bottom of the Tools Pallet, beneath the Foreground/Background Color swatches, you'll notice two buttons. One has a white rectangle with a white circle inside it. That's Normal Editing Mode, what you use most of the time. The other button is a white rectangle with a dark circle. That's Quick Mask Editing Mode, which we're going to explore now. Click the Quick Mask button now.



A dialogue box will appear. Click Selected Areas. Next to the color swatch (it defaults to red, don't worry about it), there's a box labeled Opacity. Make sure that says 75% if it doesn't already. Click OK.



Select the Brush tool. Pick a firm round brush, of a size that will let you trace details easily. Trace around the outside edge of your object. Don't wander out into the background. If you do, the Eraser tool works fine. You just want to get as exact an outline as you can so you won't have to clean up much later.



Fill in the object. You may want to select a larger brushtip at this point. Fill the object completely, leaving no blank spots. Unfortunately, the paintbucket tool doesn't work in this mode. You have to use the paintbrush to fill.



When you've filled the object and are happy with the way the edges look, click the Normal Mode button.



Everywhere you painted over will now be selected.



At this point, you can use the Layer menu to Create New Layer (via Copy or via Cut) if you want the item to float on its own layer.



If your aim is to extract the object, you must go to the Select menu and pick Invert first.



Now everything BUT your object is selected.



Using the Edit menu, pick Cut to delete the background.



Your image is now extracted. You may notice some stray pixels around the edges you don't want. Clean up with the Eraser tool set to a small size.



Your object is now ready to be pasted into another photo.



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