Adobe Photoshop Tutorial. Copyright Michael B. Karbo.

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    21. Quick masking

    Now you will see another smart technique for selection. It is called Quick masking and is actually the opposite of a selection.

    Getting ready

    Start by retrieving the picture honey.jpg from the home page for this booklet.

    1.   Open the picture in Photoshop. Then make a double click on the layer Background in the layer palette:

    2.   Rename the layer to glass. Now we can work freely with the layer’s pixel content. Save the picture as honey.psd.

    3.   The thought with the exrercise is that you are going to remove background, since the glass will be incorporated in a later exercise.

    4.   Select the lasso tool (press l). Then place a casual selection around the honey glass.

    5.   Activate the Quick masking tool by clicking on the button in the bottom of the tool box (you can also use the letter q):

    6.   Now a red membrane appears across the outer areas of the picture. That is the mask, which covers everything that you have not selected.

    7.   The idea is that you need to paint on in the selection, until you isolate the glass completely. Choose black for foreground color and white for background color (press d).

    8.   Select the brush tool (press b). Make a right click somewhere in the picture and choose a soft brush, in size 17. Close the dialog box by pressing Enter.

    9.   Now paint with black as close as possible to the edge of the honey glass. When you paint with black, you reduce the selection. You can see that in the quick mask, as the red area enlarges:

    10. If you get too close to the edge, you need to reverse foregrund and background color (press x). Then paint with white color – that expands the selection, here you need to paint from inside the glass and out.

    Save the selection

    When you think the selection is acceptable, you need to return to the normal mode (without quick masking).

    1.   You can easily turn quick masking on and off. You do that by pressing letter q, which is easy to remember, since it stands for Quick mask. Try that, press q a couple of times.

    2.   Finish by seeing the selection in stead of the red mask.

    3.   Choose a great enlargement. Hopefully you get a selection, which follows the glass closely:

    4.   You can now smooth the selection: choose menu items Select --> Modify --> Smooth:

    5.   Enter the value 10 pixels, and click on OK:

    6.   It is smart to smooth a selection like this, where we have a geometrical well defined selection. When the selection is made with brush in an express mask, it can have somewhat choppy edges. The smoothing takes care of that.

    7.   Now you need to save the selection. The selection has to be stored in the image file, so it can always be read back in. That is easy; you just make a layer mask. Click on the small button in the bottom of the Layer palette:

    8.   Then two things happen. The picture background is removed, and you see a mask icon in the layer beam (see Figure 53).

    9.   Save and close the picture (press Control+s and Control+w).

    Figure 53.The selection is saved as a layer mask.

    Express masking is a real smart function in Photoshop. You work in a special mode, where the non-selected is covered by the mask, which is seen as a red membrane. The selection can be increased, decreased and be worked on in innumerable ways by using various brush tools etc. And while you work, you can shift quickly between editing in normal and express mask mode by pressing q.

    Finally it is smart to convert the selection to a layer mask, so it can be saved in the image file (as long as we stay with Photoshop’s own PSD file format).

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