Getting to Know Quick Masks in Photoshop CS2
In Photoshop CS2, masking is essentially just another way of making a selection. Instead of defining your selection with a selection outline, masks define your selection with 256 levels of gray, which allows you to have varying levels of selection. Photoshop masks or protects unselected pixels from any commands you execute. Photoshop doesn't mask selected pixels, making them fair game to any executed commands.
Making a Quick Mask
As you can probably guess from the name, the Photoshop CS2 Quick Mask mode enables you to create and edit selections quickly without having to bother with the Channels palette. Although you don't really create an end-product mask per se, the way you go about getting your selection is "mask-like." They are also user friendly in that they enable you to see your image while you're working. You can begin your Quick Mask by using a selection tool or a painting tool. After you have your Quick Mask, you can edit the mask using any painting or editing tool.
Quick Masks are temporary, so if you create one you really like, be sure to choose Select --> Save Selection at the end of the following steps. (Note that you have to be out of Quick Mask mode to do this.) That way, you can save the selection as an alpha channel. With an alpha channel, you can easily load or access the selection repeatedly.
Follow these steps to create your very own Quick Mask:
1. Open a new document and, using any selection tool, select the element you want in your image.
Don't worry about getting the selection perfect. You can fine-tune your selection after you have the Quick Mask in place. Note that you can also just paint your mask from scratch, but starting with a selection is easier.
2. Click the Quick Mask Mode button in the Tools palette.
A color overlay covers and protects the area outside the selection. The selected pixels are unprotected.
3. Refine the mask by selecting a painting or editing tool.
Paint with black to add to the mask, thereby making the selection smaller. Even though you are painting with black, your strokes will show up as a red overlay. This red overlay is a visual carryover from back in the day when artists used Rubylith (red transparent material) to mask portions of their art during airbrushing.
Paint with white to delete from the mask, making the selection larger. Paint with a shade of gray to partially select the pixels. Partially selected pixels take on a semitransparent look, perfect for feathered edges.
4. After you finish editing your mask, click the Standard Mode button in the Tools palette to exit the Quick Mask.
The overlay disappears and a selection outline appears. Your selection is ready and waiting for your next command. The selection outline correlates with the unmasked or selected areas of the Quick Mask. Don't be surprised if the wispy or soft edges you so diligently selected aren't readily apparent when you switch back to normal editing mode. When you composite your selected image with another, your hard quick masking work will be evident.
Changing Quick Mask options
You can change Quick Mask options by double-clicking the Quick Mask Mode button in the Tools palette.
When you add a Quick Mask to a selection, by default a red overlay covers the selected area. The overlay has an opacity setting of 50%.
In addition to changing the color (to provide better contrast with your image, perhaps) and opacity of the overlay, you can also choose whether you want the overlay to represent the masked (unselected, protected) areas or the selected (unprotected) areas.