Although I don't like or use the mask feature in PSP very often, I found a use for masking that I can show pretty quickly and clearly.

Here is the story... ( and there is a moral at the end )

Four of us are working on a image. The base image, shown below, was created by our own HOST Comp Rosy in Poser 4. She send BigBaldo.jpg to me. I used it as a background in Poser 4 over which I positioned and posed a lovely female haggish character and matched the basic lighting directions and intensities with the base image.

I rendered the Old Fat Gal over a neutral grey background in Poser..

I opened both the BigBaldo.jpg and OldFatGal.jpg in PSP. My goal was to composite the OFG into the BigBaldo image making it look like she was always there. Click on the links above or the images above and save the larger images to work in in PSP.

Rendered in the right position relative to where I want her in the final composite, I copied the OldFatGal image in its entirety by right clicking on her title bar and picking Copy from the flyout box.

Then I right clicked on Big Baldo's title bar and picked Paste As a New Layer from the flyout box.

Pick the Magic Wand Selection tool and set the Tools Options Palette to the
following.

Match Mode= RGB Value
Tolerance = 10
Feather =0

Click in the grey background area to select it.

Invert the Selection to select just the figure.

Go to Selections > Invert on the Menu Bar.

We need to get rid of a bit of grey between her thighs and around her hair that should be transparent.

Use the Zoom Tool and drag it around her knee area.

About a 6:1 zoom ought to give you a good view of the left over grey area.

Select the Magic Wand again, and set the tolerance on the Options palette to 18.

Hold the CTRL key on the keyboard and click in the grey area to remove these pixels from the selection.

By increasing the tolerance, a larger range of grey pixels is selected.

Still zoomed in close, press the W key on the keyboard to bring up the Overview navigator.

On this window, click drag bounding box up over the woman's head. Notice that as you move the overview area, the window scrolls to follow.

Hold the CTRL key and click just under the ear on the right side of the image to get rid of the neutral grey pixels still in the hair.

Go to Selections > Modify > Contract... on the Menu Bar.

Set the value to 2 and press
OK.

Go to Selections > Modify > Feather... on the Menu Bar.

Set this value to 2.

Although the selection appears the same, the edges are partly transparent.

WOW.. What is going on?

Fire up your layer palette if it's not visible with the L key on the keyboard.

Notice that Layer 1 has a face beside the eyeglasses icon.

That indicates a Mask is active on the layer.

Since the woman is perfectly positioned, all we need to do is remove the elbow area and part of the legs and feet (Unfortunately, her best assets) and she will look like she is meant to be in this picture.

We will edit the Mask to do this.

First, on the Layer palette on Layer one, click the eyeglass tab on the right panel to get back the merge mode and transparency sliders.

Slide the transparency to about 30 percent so you can see the intersection of the elbow and the fat bald guys head as well as the intersection of the OFGal's legs with the red sweater and the chair.

Selection type = Point to Point
Feather = 0

Uncheck Anti Alias.

Make a selection around Baldo's head where it meets the elbow.

From Selections on the Menu bar, do a Modify contract by 2 pixels then a Feather by 2 pixels.

Let's modify the Mask. Select layer one on the Layer palette

Go to Mask on the Menu bar and choose View Mask.

Note the area that is visible in the image is normal colored and the area we cannot see
on that gal layer is red.

A Mask hides stuff.

Go Back to the word Mask on the Menu Bar and pick Edit Mask.

Caveat: With Edit Mask toggled on you edit only the mask. With it toggled off, you edit the actual layer!

Note that the color palette changes to all greys.

A mask in actually an 8 bit
greyscale image superimposed over the main image where each shade of grey represents a degree of transparency.

Pick the Paint Brush tool. O

On the Tool Palette set the options as follows:

Shape = Round
Size = 17
Opacity = 100
Hardness = 100,
Step = 25
Density = 100.

Set the foreground color to pure white.

When you paint on a mask with pure white, RGB 255, 255, 255, the underlying area, the hidden pixels are exposed 100 percent.

Try painting in the selected area with the brush. Notice how the grey pixels show up again?

That's not what we want!

We want to make the elbow invisible! Press UNDO, CTRL + Z on the keyboard until the area just painted goes back to red.

Switch the Foreground color to pure black and Paint over the selected area. Notice the elbow goes red, meaning its masked, or hidden. Therefore painting with pure Black, RGB 0,0,0 hides the pixels 100 percent.

Toggle the View Mask off by Mask >View Mask from the Menu Bar or by pressing CTRL + ALT + V on the keyboard.

Remove the selection. Zoom out to 1:1. On the layer palette move Layer one's transparency slider to back to 100 percent.

Now the elbow is "behind" the Fatguy's head. More comfortable for him for sure. ;)

1. Slide the layer one opacity to 30.

2. Zoom in on the legs where they hit the shirt.

3. With the Lasso tool, set as before, click a selection around the shirt border and the
chair and around the legs in the shirt and the chair.

4. Contract the selection

5. Feather the selection

6. Turn on View mask

7. Turn on Edit mask.

8. Pick the brush tool set to black for the foreground color.

9. Paint over the whole selected area, until all those legs and feet pixels are totally
red. (Masked, Hidden)

10. Turn off the Mask > Edit

11. Turn off the Mask >View Mask

12. Slide the transparency slider to 100 percent for layer one on the Layer Palette

13. Remove the selection.

That should do it.

The old fat gal is "behind"
the chair and in front of the wall.

Caveat: Save now in the .psp format to save the Mask information with the image!

OK, you ask, how could one do it any other way?

I could have selected the OFG in her own image, then copied that selection and pasted to the BigBaldo image as a new layer. Then I could have positioned her and erased the areas I wanted to hide, either by selecting those areas and hitting the delete key or by using the eraser tool to erase them.

Same effect except for one thing.... and here is why I used Mask today instead of just erasing the parts....

Let suppose the next person to work on this image, like maybe Jinny, wanted to move my girl to the right. If I had just erased the areas here is what would have happened.

But move this layer to the right some?

UGH! Her parts are totally missing! Never to be retrieved again, because the actual layer
has been altered.

With the mask method, however, if Jinny wants to move the gal over, all she has to do is edit the mask with white paint to reveal more of the underlying layer and
voila, saved. :)

The moral of the story is...

If you plan on changing the position of a layer several times, especially after hiding parts, and after saving and closing the image, use masking, as it preserves the underlying layer. Masking is non destructive to the actual layer!

If you know you are not going to move the layer ever ever again, I think its quicker and easier to select the areas you want gone and do an edit clear. After you save and close the image, that layer information is gone, permanently changed.

Your choice. See finished image below.

You can go on with this to add a perspective shadow if needed to make the image more realistic using a third party plug in like EyeCandy 4, Shadow lab.