Adobe Photoshop : Selecting

One of the most fundamental skills of digital image editing is the ability to efficiently and accurately select portions of an image you wish to edit. In selecting, you use a certain set of tools to tell Photoshop to isolate a particular portion of your image. In theory, the process is identical to highlighting text in Microsoft Word. The tools, however, are different.

Photoshop provides you with several tools to define selections. The most important are the Marquee, Lasso, and Magic wand (it might be helpful to experiment with them as you read this section!).

The Tool palette

Tools with a small arrow in the lower right hand corner contain more than one option. To access these options, click and hold on the button, then slide your mouse over until the option you want is highlighted.

Marquee: Located near the top of the tools palette, the marquee tool enables you to define a variety of geometric selection outlines. With its four options -- rectangular, elliptical, single row, and single column -- you can select regular geometric portions of any image. The Marquee tool is useful for cutting large parts of an image, but in general it is less useful for selecting more organic shapes.

Lasso: Situated just below the Marquee, the Lasso tool allows you to create freeform selection outlines. Generally speaking, you use the Lasso by dragging it in a freeform path around the object you want to select. In those cases where you might want to outline a selection with straight sides, a polygonal lasso option is available as well. You can use the polygonal lasso to define a straight-sided selection without being limited to only four sides by the rectangular Marquee. The magnetic lasso can be a really usefull tool for selecting objects that have a strong contrast with their background.

Magic wand: Conceptually, using the Magic Wand tool is easy: you just click on the image with the wand and it selects all the neighboring pixels whose brightness values fall within a predetermined range. In practice, it takes some finesse and trial-and-error to get the results you want. Try it out on your own. If you want a more in-depth explanation of how the magic wand selects pixels, click here.

Building selections

With most selection tools, you can add to a selection you've already defined by holding down the Shift key and then clicking on another part of the image. This lets you build a complex selection incrementally (in case you don't grab everything the first time) and is especially helpful when using the Magic Wand. To subtract from a selection, use the Alt key.

Ctrl-D (Deselect) is a usefull for shortcut for disappearing your current selection (but not the content inside the selection).