How to use the Quick Mask Mode

original tuto (in french)

This tuto is going to teach you how to extract sub parts of a picture without using the magic wand (which is not precise) and faster than using the pen tool. An example where using the Quick Mask Mode would have been useful : this topic...
The Quick Mask Mode is unfortunately no very used, but after you read this tuto I'm sure you'll use it more often.

Let's take an example : I want to extract the girl in the foreground.

Try with the Magic Wand tool : impossible ! it doesn't work correctly because the caracters around have the same skin and chothes colors...

So what are we going to do ? Here's the solution : use the Quick Mask Mode.
It's very easy to use it, first of all we delete any already present selection by doing Ctrl+D. Then we set the Quick Mask Mode by clicking on the right button in the Toolbar :

We can also press Q.

Now let's select the Brush tool (Diameter depends of the precision you want and Hardness must be at 100%)

Set black in foreground color :

Then the selection starts : we're going to "paint" the zone we want to select (if needed, zoom on the picture to be more precise).
And now, miracle, the brush paints in red
This red trace is actually the zone wich will not be in our future selection.

If needed, we can correct little details with a smaller brush :

Once the trace is done, we reput the Standard mode to use our new selection by pressing Q :

The non-red zone becomes selected :

Well, it's done, we can now extract the part from the picture, change background, etc...
Examples :

Additional remarks :
You can also use this mode in the way normal selection/mask selection (quite useful when you've already started to select in the picture)

You can adjust Brush opacity to change selection opacity :

We can use other tools than the Brush mais this one is the easiest the make standard selections...

PS: I translated the tuto by myself (I'm french), so there can be mistakes (I think there are ) : just tell me

Nice Translation K-net and thank you very much This is what I've been looking for a long period

Well / Wow / Now

teach is better

Selected

Additional Remarks

Edited !

Once more, thank you, Neil

You're welcome K-net

it should be remarks

Thanks again, edited

nice tuto ! thank's you

and one more to k-net          

So nice translation ! Good Work K-Net !  

Thanks

Good translation k-net ! And nice tutorial too !  

nice tutorial!    nice choice of which part to extract too!!