In Photoshop, a selection is a defined part, segment, or region of an image that is purposefully chosen for editing or modification. A selection can contain an entire image, or a very small part of an image. As a matter of fact, a selection can be made in any number of shapes and sizes.

Selections are so important in Photoshop that there are three lessons (lesson 3.1, 3.2, and 3.3) dedicated to exploring selections in detail. However, before you get into the details of working with selections, you should have a basic familiarity with the tools used to make selections.

The simplest selection tools are the marquee tools. Marquee tools are used for making selections in the form of standard predefined shapes. The default marquee tool in the Photoshop toolbox is the rectangular marquee.

As one would expect, the rectangular marquee tool is used to make rectangular selections from an image. To use the rectangular marquee tool, click on it, and then put your mouse pointer on the image you are editing. Hold your left mouse button and drag your pointer to create a rectangle from light and dark flashing dashes. The area bounded by the dashes is a selection.

The small dashed rectangle visible on the dune defines a selection.

To access the other marquee selection tools, click and hold the rectangular marquee button (notice that the button has a small triangle in the lower right indicating a menu of tool variants).

The sub menu contains the following variants on the marquee tool.

The marquee variants work much like the rectangular marquee. Click on the marquee tool of your choice to select it and then click and hold your left mouse button on the image to control your selection.

The lasso selection tools are used for making selections in the form of varying shapes that cannot be made with the marquee tools.

To see the lasso tool variants, click and hold down the lasso tool button.

The lasso tool variants are:

The magic wand selection tool has no variants. It is used to make selections based on shades of colour. You can set a tolerance ranging from 1 to 255 that will influence the selection. A lower number will allow you to select only colours that are close to the colour you specify for a selection. A higher number will allow you to select a range of colours that varies further from the colour you specify for a selection. The tolerance option for the magic wand can be set up in the Photoshop options bar.

Whenever you use a selection tool, there will be selection option buttons available in the options bar. The first button on the left (the white square with the grey square inside it) is the new selection button. If you click this button, any existing active selection will be deactivated when you make a new selection and only the new selection will remain.

Moving right, the next button is the Add to selection button, which will allow you to add to an existing selection. The third button from left to right is the Subtract from selection button, which of course lets you subtract from, or remove part of a selection.

Finally, the last selection button is the Intersect with selection button, which will allow you to select the region formed by the intersection (overlap) of two selections.

You can combine the selection tools with the buttons on the options bar to help you select the precise regions of the image that you require.

The crop tool is included in the discussion of selection tools, because it works in a similar way. First you select the crop tool from your toolbox and then you use your mouse to make a selection in the same way that you would use the rectangular marquee. When you stop holding your left mouse button, the region of the image that will be cropped will have dark shading over it.

The light part of the image will be retained. You can resize a cropping selection by using the move handles (small squares located around the selection perimeter). You can also drag your mouse pointer just outside a selection to rotate it clockwise or counter clockwise (rotation is in the direction you drag your pointer). To crop the image, press the Enter key.

Before you commit to cropping an image you can right click on the light area inside the cropping selection (the part that will remain) to display a pop up menu. This menu will consist of two items, cancel and crop. If you click cancel, the cropping action will be cancelled. To crop the image, click the crop menu option.

As with the other tools in the toolbox, when you select the crop tool, options pertaining to its use will appear in the options bar.

The move tool will allow you to move a selection by dragging it with your mouse or by using the arrow keys. The arrow keys will only move a selection in small increments, unless you press shift at the same time. When you click the move tool, options for its use will appear in the options bar.

You can use the slice tool to divide an image into smaller rectangular regions. If you click and hold the slice tool button, you will be able to choose the slice select tool. This tool allows you to move and resize slices with your mouse pointer.

The slices you make can be saved as individual files, which is advantageous for web site design. The slices can be used to make web images load faster, or to make different parts of an image link to different locations in a web page or website. Again, when you click the slice tool button, options for using the slice tool will appear in the options bar.

This image has been divided into rectangular sections with the slice tool.