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slejhamer
27th of March 2003 (Thu), 06:08
There have been a number of posts recently on how to isolate a subject in an image. In Photoshop, there are various methods to achieve the end result (layer masking, the lasso tools, the magic wand, etc.,) each with varying degrees of complexity and precision.

One that is often overlooked, but which can give you the greatest amount of control, is the pen tool. You can easily make selections right down to the pixel, and you don't need a Wacom tablet or other special hardware.

Once understood, the pen tool is as easy to use as any of the above-mentioned techniques. In fact, it is harder to explain than it is to use. (Note: I don't know if the pen tool is available in the "lite" versions of Photoshop, so this technique may only be available to users of the "full" versions.)

1. Make a duplicate layer so you don't mess up your original. (You shouldn't be working on your original anyway... )

2. Zoom in as much as needed, until you get the level of edge detail you want. 400% is useful, but you can go further if necessary.

3. Click on the pen tool. When you use this initially you will create a "path," not a selection, but we'll deal with that later.

4a. Click around the edge of the subject you want to isolate. Use small spaces between clicks for curved areas with fine detail, or large spaces between clicks for straight edges. Easy so far.

4b. If you click in the wrong spot, hit ctrl-z to undo the last click. (Sorry, I don't know the Mac code, but it's edit > undo on the menu.)

4c. A big advantage over the lasso tools: if you get to the edge of your window, simply move the window slider over. The pen tool waits for the next click, unlike a lasso which will extend out of the window if you drag it there.

4d. When you complete the selections and reach your starting point, the path completes itself as a solid line around the subject.

5a. In the Layers/Channels/Paths palette, click Paths.

5b. At the bottom of the palette are a series of buttons; click the third button (gray circle) from the left which is tagged "load path as selection."

5c. Your path now becomes a selection with the famous marching ants.

6. If desired, feather the selection a pixel or two. I find that feathering 1 pixel twice is better than feathering two pixels once, but the amount you use depends on your image resolution and the amount of edge softness you want to achieve.

7. Now that you've made a precise selection, what you do with it next is up to you!

Give it a try and let me know if this is helpful.

dtrayers
27th of March 2003 (Thu), 07:33
I have PS Elements 2, which doesn't have the Paths palette, but I was able to find a workaround.

I followed steps 1 - 4 as you did, but I did my drawing with the pen on a new layer with no background.

For step 5, I then used the paint bucket to fill the outline with a solid color (doesn't matter, just make sure the paint bucket option is set to "contiguous" and "all layers" is not selected. You now have a solid colored "mask" of your outline.

Then just CTRL-click on the layer, and it will create a selection of the outline of the shape you just filled.

You can then save the selection, or use the selection as part of a layer mask.

Thanks for the useful tip.

lziering
27th of March 2003 (Thu), 07:47
If you are tying to isolate the subject from the background to create a composite then what you have suggested is one of the most difficult ways to isolate a subject. Next time try the "Extract" command under the filter menu. It will take about 1/10 the time.

slejhamer
27th of March 2003 (Thu), 08:52
lziering wrote:
If you are tying to isolate the subject ... Next time try the "Extract" command under the filter menu.


A good suggestion, lziering, very similar in function to (and maybe better than) Procreate's "Knockout" plug-in.

I agree with you entirely that the pen tool can be the most time consuming, though I wouldn't call it "difficult." (I go out of my way to avoid things that are difficult. :) )

I have tried extraction - only once, admittedly - but found it lacking in areas of low contrast. Even the "smart highlighting" option suffers when the selection area is not of high contrast and sharpness, requiring lots of use of the edge touch-up and clean-up tools. With the pen tool I can select what I want the first time, with the precision of a hardware pen tablet.

Also, after all the fine-tuning, I found extraction to take a little less time, but not 1/10th. That may have been because it was my first time and I was not familiar with it, but the pen tool also gets easier/faster the more you use it.

That said, as I think about it further, extraction may be superior for hair and other wispy parts of the main subject. I will give it another try, and thank you for reminding me that it's there.

PS: For anyone interested, there's a great tutorial on the extraction filter, which also comments on the pros and cons, here:
http://www.peachpit.com/content/downloads/peachpit/wow_downloads/ps6.wow.book.extract.pdf

Kevin Connery
27th of March 2003 (Thu), 15:49
Selection method is highly dependent on the subject content.

Using the pen tool to isolate, for example, edges of grass or hair, or other similarly 'fuzzy' items is an exercise in masochism; using a lasso or other pixel-based tool to outline a car against a comparable colored background is similarly silly.

Color Range, Magic Wand, using the individual color channels (remember; you can use R, G, B, C, M, Y, K, L, A, or B as the starting point for ANY selection), the pen tools, the lasso tools, the marquee tools; they're all available, and can be mixed to suit your needs.

"Tools are for using."