Application of PS Mask tool

Masks in the PS of the application is quite extensive, the mask is the biggest feature can be repeatedly modified, but it will not affect the layer of any structure. If the mask adjusts the image is not satisfied, you can remove the mask original image and reappear. It's a very magical tool.
We usually say the mask mask, in fact, there are several kinds of masks, I know there are four kinds: one is a quick mask, the second is a layer mask, three is a vector mask, and four is a clipping mask. The inner connection between them does not matter to him.
First, Quick mask:

I only use it to create a constituency, look at an example: a lot of grinding in the course of the requirements of the MM facial features to stay out, only to wear facial skin, I use this quick mask. Where is it? Here, press Q is OK.

Below we use it to select the facial skin of MM, point that button, select the brush, the foreground color is black, besmear you want to grind part, tu boundary with white brush tu come back, is it very convenient to go back and forth besmear?

Why is it red? Red is right, the default is red. The following point to create a quick mask to the left of the button, exit the quick mask, press Q is OK.

See the constituency, don't worry, mask mask, just the red part is blindfolded, not we want, the reverse election on the line Bai! Copy and see the effect.