You are going to need Photoshop for the Mac. The EXTRACT filter is the best way to do this, though it takes some practice and some knowledge of some tricks. Here is how to use Extract in Photoshop.
1. Open your photo in PS....
2. Also open the photo or background you want to use as your backdrop. If you do not
have a photo, just create the color or whatever you want with a new
canvas (File - New). Unless it is a solid color, I like to have the
background larger than my extract so I have room to play with it, but at
any rate, be sure the resolution of your background and extract photo
are the same.
3. Minimize your background photo so only your photo you want to extract
from is visible.
4. Go to Filter - Extract
5. Oops... nearly forgot, the extract filter only works on 8 bit files,
(at least in CS, newer versions of PS might support 16 bit with extract,
I don't know).
6. Ok.. you now have the extract dialog workspace open with your photo
displayed. You will be using the Edge Highlighter tool, it is the top
tool on the toolbar.. it looks like a marker. You will be tracing around
your subject(s) that you want to extract. Be sure and watch for any
spaces inside, such as between legs, that you may need to trace around
also. The object is to have half the edge of the trace, (it is green on
my PS.. I think that is the default color), inside your object you want extracted, and the other half on the background you want to remove. In
other words, the edge of your object will be inside the trace line. It
acts just like a highlighter so you can see your object edge inside the
green extract path. Here are some tips that will make your trace do a
better job. You want to use a small brush size for sharp, well defined
edges, such as along clothing. You want to use a larger brush for less
well defined edges.. such as hair. You will find it much easier to work
if you zoom in on the photo. If you try to do the trace with the photo
at the smaller size in the display, you will actually be using a brush
MUCH larger than needed. So zoom the photo up larger. It kind of makes
it a hassle moving the photo around as you trace, but it is necessary.
7. Now when you have traced all around your subject, you can zoom back
out so you can see the entire photo. Your trace line should appear quite
small around most edges, a little larger around hair.
8. You will now fill the selection. This is done with, you guessed it,
the Fill tool. It is the bucket looking tool, the second tool from the
top of the tool bar, directly under the Edge Highlighter tool you have
been using. Place the fill tool inside your trace and click once. Your
trace should now fill with a light blue tint. If you see any blue tint
spill out of your trace, then you did not completely enclose your
subject. If you see that, do a Command Z (Control Z on Windows) to undo,
and retrace the area you missed. Then Fill again.
9. With a good blue fill inside your trace, you can click the Preview
button to see how the extract will look. If you feel you want to keep
working with the trace you can, but it will never be perfect, but it can
pretty well be fixed later. If the extract looks fairly good in Preview,
go ahead and click OK to perform the extract.
10. The extract box will disappear and you will have your extraced
subject(s) on a transparant layer. You usually always will have to do
some repair.
11. One of the first repair steps is to simply duplicate the layer.
Press Cmd. J (Cntrl. J on Windows) to duplicate the layer. This will
help to get rid of lots of the "junk" from the extraction. Then press
Cmd. E (Control E on Windows) to merge the two layers.
12. Now to work on some of the other dropouts you may see. Use the
History Brush (the brush with the little curved arrow on the top of it.
The history brush will paint back in any part of your extracted subject
that may be dropped out.
13. Ok.. still with me? :-) Now open your background photo that you
minimized earlier. It is best to drag this background photo onto your
extracted photo. The reason for this is it still allows use of the
history brush if needed later.
14. The background is now all you will see. What you do now is go to the
layer palette, (you must have your layer palette open), and drag the
layer with your background photo behind the layer with your extracted
photo. Your extracted person will now appear in front of the background.
15. Now is where it can get tricky. There will usually be some "junk"
you will need to clean up.. kind of weird looking squiggles around the
subject and such. You should zoom into 100% to closly inspect the photo.
You will notice in your layer palette that one of the layers in numbered
"0". You will need to click on the 0 layer and select the Eraser tool.
This is where you will be doing work around hair also. You will set a
soft brush and at a very low opacity.. maybe around 5%. You will then
brush around hair to very gradually replace hair with background. If
hair is excessively fly away, there is still not much choice but to
totally erase away some of it. You can work with opacity as needed. In
other areas of the photo, you can usually set opacity to 100% to erase
away junk around the extracted subject. With the eraser selected, you
can select an air brush from the brush drop down menu to work around hair... sometimes it makes a better blend of hair and background.
16. When you are happy with the extraction just flatten the layers.
steve