5.Next,
we want to select and remove the tower and trees out from the sky. To
do this, let's use the Magic Wand. This tool is useful for selecting
broad areas of color that are very similar, like our sky here. It's not
very useful when the area has lots of color variations, like the trees
in this image.
Note the Options palette for the Magic Wand. Make sure "Anti-alias" and "Contiguous" are
checked. This tool works by selecting all the pixels that are similar
to one another in color and touching the pixel you click on. "Tolerance" determines
how many shades of color it will pick up. Experiment with different
values and clicking on the sky. Try 5, 10, 20 and 70. Note that small
numbers will only select a small area. Larger numbers will select a
larger area, but may also pick up areas you don't want selected, such
as parts of the tower. So, how can we use this tool to select the entire
sky? There are two ways. Let's use both:
Method one: Set your Magic Wand to a moderate tolerance value, say
10. Click in the middle of the sky. Now, hold down the shift key and
click again, this time on an area that wasn't selected before. By repeating,
you should be able to select most of what you want.
Method two: With most of the sky selected, pull down the Select menu
to "Similar." Photoshop picks up all pixels of a similar color. Repeat
until you have the entire sky. Note that this will also pick up areas
that are trapped, like the blue bits showing through the trees. It
doesn't work so well if you have areas of a similar color you DON'T
want selected.
OK, we've selected the sky. But we want the tower and the trees.
How do we get them? Pull down the Select menu to "Inverse." Now, everything
that was selected is released, and everything that wasn't is selected.
In general, by moving back and forth between selection and inverse
selection, and using the Magic Wand, the Marquee tool or the Lasso,
you should be able to select just about everything you want, and leave
out everything you don't.
When we inverted our selection, we lost some of the pixels at the
outside edge of the tower. Pull down the Select menu to "Modify >" and
over to the "Expand" submenu. Type in a 1 and click "OK." We've added
one pixel all around our selection. There are several handy commands
in there for modifying selections.
Let's also apply a little feathering, for a smoother look. Pull the
Select menu to "Feather…" and type in "1" and click "OK."
6. You should have just the tower and trees selected now. Go
to the Edit menu and select "Copy."
7. Now,
pull the File menu to "New." Notice that the dialog box fills in the
size and resolution of the document for you. This is based on the information
you have on your clipboard. Click "OK."
8. Select "Paste" from
the Edit menu, pasting the tower/trees image into your new document.
I think it's about time to save. Select "Save As" from the File menu.
Save the file to your desktop, or a directory you can remember later,
and call it "mydemo2.psd"
Next,
we want to select and remove the tower and trees out from the sky. To
do this, let's use the Magic Wand. This tool is useful for selecting
broad areas of color that are very similar, like our sky here. It's not
very useful when the area has lots of color variations, like the trees
in this image. 
7. Now,
pull the File menu to "New." Notice that the dialog box fills in the
size and resolution of the document for you. This is based on the information
you have on your clipboard. Click "OK."
8. Select "Paste" from
the Edit menu, pasting the tower/trees image into your new document.