Getting To Grips With Photoshop CS4’s Magic Wand Tool
The Magic Wand is one of three tools in Photoshop which are dedicated to making selections. When I run courses on Photoshop, tools like the magic wand and the clone tools are usually the ones which everyone finds the easiest to start using because they give such immediate results. The Magic Wand works by selecting colours within the image adjacent and similar to any pixel that you click on. Pixels of dissimilar colour act as barriers to selection and so the selection ripples outwards from the point you click on.
Naturally, it’s quite rare to get a “hole in one” when you are using the magic wand to make selections. Typically, you will select part of the area that you want and you will then need to add and subtract from the selection, perhaps switching to the other selection tools from time to time. Photoshop offers you two ways of modifying a selection: you can either use modifier keys on you keyboard or activate the modifier icons on the options panel normally displayed below your menu bar.
To subtract from the selection, hold down the Alt key and click on the part of the selection which you wish to deselect. To add to a selection, hold down the Shift key while clicking with the Magic Wand on a part of the image which is not yet selected. The selection modifier icons are situated on the left of the options panel at the Photoshop interface. There are four of them: new selection, add to selection, subtract from selection and select intersection. These icons effectively allow you to change selection mode on a permanent basis. Thus, for example, you could click on the second of the four icons when using the Magic Wand and click continually on different parts of a subject until it was completely selected.
If you want to select a subject against a uniform background such as a wall or the sky, a simple trick is to use the magic wand to select the background and then invert the selection by choosing Select – Inverse. A slight variation on this technique is to make a rough selection which completely encloses the subject as well some of the background and then to use the Magic Wand in subtract mode to remove the background from the selection.
You can control the number of pixels which the Magic Wand selects when you click on part of the image by changing a setting called tolerance. Tolerance determines how far a pixel can vary from the pixel that you click on and still be included in the selection. The default tolerance is 32 and the maximum is 255.
