Mastering the Magic Wand Selection Tool in PSP 7

Short Tip for November 15, 2001

Wanda, the Wicked Witch of the Toolbox, causes more frustration than almost any other tool in PSP, yet it is one of the essential tools to master for image editing.

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More often than not, people ask for help with the Magic Wand tool. They are on the brink of a digital mental breakdown and basically at a loss as to how to control it.

Just when they think they have her figured out, Wanda pulls some really, really bad magic tricks.

"Peace, sisters and brothers, it's only a computer generated tool, let it not eat you from the inside out," I say. "She will respond to your commands if you understand her and keep her on a short leash."

Let's explore how the Magic Wanda operates.

In PSP, open the file Testgradient.jpg

Web Users:
Right Click the image on the left, save to your hard drive and open in PSP.

PDF Users: Click here to download image from the Net.

This black and white gradient filled image contains 256 shades of grey.

1. RGB Value Match Mode: The RGB match mode picks pixels based on the amount of Red, Green and Blue in them.

Pick the Magic Wand from the Tool box.

On the Tool Options Palette, pick RGB for the Match Mode.

Set the Tolerance to 10, feather 0 and Uncheck Sample Merged.

The Tolerance sets how similar the values of the adjacent pixels must be to the pixels clicked on to be included in the selection.

At low settings, the values must be close. At higher settings the tolerance is greater unleashing Wanda to include more pixels.

Click anywhere in the image and notice the selection created.

Press the Shift key and click again in the image away from the first selection to add another area to the selection.

Do this a third time. Note that the amount of pixels added is about the same amount each time.

Remove the Selection.

Set the Tolerance to 20 and repeat the select and shift select.

Notice how much more of the image is deemed to be worthy of inclusion by Wanda.
Remove the Selection again and change tolerance to 50.
Click once in the image to see how many pixels are selected.
TRICK: When selecting based on RGB value, you may find it almost impossible to select a whole desired area in one pop.

I suggest setting a tolerance of 10 to start. If more pixels are needed in the selection, hold the SHIFT key and click again to add to the selection.

Feel free to change the tolerance setting between clicks if necessary to fine tune the amount of pixels added.

You can also change any of the Selection parameters between shift clicks.

Feel free to change to the Rectangular Selection Tool and any of its variants on the Tool Options Palette, or the Freehand Selection Tool and any of its variants.

Exercise:

Web Users: Open motorbike.jpg in PSP by Right clicking image on the left, saving to hard drive and browsing to and opening in PSP.

PDF users. Click here to download the image from the Net.

Zoom into the orange light on the front of the fender.

Get Wanda.

On the Tool Options Palette, select RGB Value and set Tolerance to 10.

 

Click in the orange light.

Then set the Tolerance to 20 and Shift Click in the adjacent orange pixels to select more of the light.

Using just the Magic Wand, select the whole light. It might take a few clicks or a dozen.

Should you accidentally add pixels you don't want, press Ctrl Z to undo the last selection you made. OR, press CTRL Key and click in the same place to Subtract those pixels from the selection.

Shift+ click adds pixels. Ctrl + click subtracts pixels.

Next engage the Rectangular selection tool.

SHIFT and click drag a box over part of the selection including pixels outside the current selection.

Note how the pixels are added.

Pick the Lasso Tool and using Point to Point Option, CTRL click and remove the pixels that are outside the orange area.

The trick is to carefully outline the orange pixels and wildly choose whatever is outside the selection, then double click to close and subtract.

That's going a bit beyond Wicked Wanda, but I thought it would make your selection life easier. ;)

2. Hue Match Mode of Magic Wand Selection.

With Hue, Wanda selects pixels based on their position in the color wheel of the hues. Let's compare how this works to the RGB Value. Zoom out on the Motorcycle image to 1:1 and remove any leftover selections there.

With Wanda engaged, on the Tool Options Palette change the Type to Hue and set the Tolerance to 100.
Click anywhere in the Yellowy fender to get a pretty decent selection. I discovered the tolerance value by trial and error.

Remove the selection.

Change the to the RGB Match Mode.

Click in the yellow fender again and the results are very bizarre.

Not only is the yellow fender chosen but most of the grey wall and the wheel holder too.

For even more weird and inconsistent results, click in a different area of the fender.

Wanda chooses differently this time.

I believe Magic Wanda Road Rage we talk about comes from this wildness with
RGB Value and high settings. Therefore, when it's a certain Hue you want to select, try the Hue match mode instead of RGB Value, even if the Tolerance needs to be substantially higher than with the RGB.

3. Brightness Value Match Mode

With Brightness, our Wanda selects pixels based on the amount of white they contain. I suggest using Brightness to choose areas of similarly bright pixels surrounded by areas containing pixels with high contrast.

Pick Wanda, set the Match Mode to Brightness and Tolerance to 50 on the Tool Options Palette.

Click in the whitewall area of the tire.

A pretty nice clean selection.

Remove the selection.

Change the Match Mode to RGB value. UGH.

Remove the selection.

Change to Hue with same tolerance settings and try that again. Double Ugh.

Mastering the selection tools is crucial to mastering image editing. Selections allow you to work on parts of an image without disturbing the rest of the image AND they are frequently promoted to layers. In other words, ya jis gotta keep on practicin' , Honey!

That about covers those settings. The other two match modes are based on opacity.

4. All Opaque match Mode: With All Opaque (called All Pixels in previous versions of Paint Shop Pro), Wanda will select only those areas containing pixels. No transparent areas will be added to the selection.
We need an image with a transparent background for this section, so close the motorcycle image without saving.

Go to File and Open then browse to your PSP 7 / Tubes folder. Pick any tube file. I chose Fire.tub.

Notice its transparent background indicated by the grey checkerboard pattern.

With Wanda engaged, pick ALL Opaque from the Match Mode on the Tool Options Palette.

Note that the Tolerance is greyed out. It's not an option with this match mode.

Click in any colored pixel in a tube image.

She picks all pixels that have ANY color to them at all, but NO pixels that are totally transparent.

That's all there is to that, so remove the selection.

5. Opacity Match Mode: Opacity selects pixels based on the opacity (transparency) value of the current pixel compared to those around it. Note that Tolerance is again active on the Options Palette.

Pick Opacity and set the Tolerance to 0.

Click in the transparent part of the image.

Only the pixels that exactly match the opacity of the pixel you clicked on will be selected, which in this case is 100 percent transparent. (On left)

Remove that selection then change the tolerance value to 200. Click in the transparent area.

All the pixels are selected. (Not shown )

Try it again with 100 as a setting and click in the transparent area of the image.

Wanda picks pixels that are about 0 - 50 percent opaque.

Remove selection then click in the colored area of the tube.

The result is approximately the same only it picks pixels that are 100 - 50 percent opaque.

As you can see, the opacity options are good only on layers or images with transparency.

These can be very powerful and quick ways to make selections.

Here is one more neat trick.

Web Users: Save posershovel.jpg on the left by right clicking on the image and saving to your hard drive.

PDF Users: Click here to download the image from the Web.

Browse to it in PSP and open.

This is a rough texture map for a 3D model, not just my bad art.

My goal is to select only the gritty bars on the left side and I am in a hellacious hurry. I want them together in the selection in as few mouse clicks as possible.

Here is how I can get them quickly.

With the rectangular selection tool, drag a rectangle surround the 2 bars.

Change to Wanda using RGB value and tolerance of around 100. ( Brightness works here too)

Press the CTRL and click inside the current selection on the white area. Wham, both bars selected together, all white gone.

A neat way to drop out a plain background eh?

And that about wraps up Mastering the Magic Wand. It's up to you to practice controlling her wild spells.

Good luck!

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