The first selection tool in the Tools Menu is the Marquee Tool. There are four marquee shapes you can choose from. To select a portion of an image with this tool click on the image and drag to create the size of the shape you want. Once you have drawn an area with this tool, you can use the arrow keys on your keyboard to adjust the location of the marquee area before actually making the selection.
To reposition a marquee while you are drawing it, click and drag to start drawing the marquee, keep the mouse button depressed then hold down the spacebar while continuing to drag. You will see that this repositions the marquee. Once the marquee is in the correct position, release the spacebar. You can then continue to drag your mouse to change the size of the marquee. Remember that you will only actually select objects that are in the layer(s) you currently have selected.
As with every tool in Photoshop, a tool bar for the Marquee Tool will appear at the top. This tool bar allows for additional options. Let’s go through this tool bar from left to right. The first icon on the tool bar shows the marquee shape you have selected. This is followed by four selection options. They are New Selection, Add to Selection, Subtract from Selection, and Intersect with Selection.
The default option is New Selection. This means that if you have the rectangular marquee selected and click and draw on your image, it will draw a new marquee rectangle selection area. If you need to deselect a portion of the selected area, choose Subtract from Selection and draw around the area you want deselected. Likewise, Add to Selection increases the selected area. You can also add to your selection by pressing shift while selecting regardless of which option you have active. Intersect with Selection allows you to draw two areas and the overlapping portion will be the selection area. You can continue to draw as many overlapping shapes as you would like until you have the correct area selected. Use these tools in conjunction with each other to easily select portions of your image.
The next option of the menu bar is the Feather option. Feathering the selection allows you to create faded edges around the selected area. Say you decide that you would like to feather the selection by 20px and then draw the marquee on the area you want selected. You may see that the shape of the selected area looks different (smaller and rounded corners if you are drawing with the rectangular marquee), but no changes will be made to your image. You will not see the difference feathering makes until you do something with your selection. If you move your selection or copy and paste your selection you will see the difference feathering makes. Anti-alias smoothes the edges of the selection.
Rectangular Marquee without Feathering
Rectangular Marquee with 20px Feathering
Selection with 20px Feathering
Moving on to style you will see a dropdown menu. Normal allows you to draw your marquee freely. But, say you know that you want your selected area to be an exact size. If you choose Fixed Size and enter the dimensions you want when you click on your image the correct marquee size will appear. You can then move the marquee to the correct location on your image.
Fixed ratio allows you to draw your marquee at fixed proportions. For example, you could enter the width as 1 and height as 2. No matter how large or small you draw the marquee on your image, the height will always be two times the width. Unlike when working with pixels, with ratios you can use numbers with decimals. If you click on the two arrows between the height and width it will switch the numbers.
The Refine Edge button allows you to refine your selection and view your selection against a neutral background so you can more clearly see how your selection will look. Select a portion of your image, and then click on this button. By default when you choose this, everything outside of your selection will appear white so you can more clearly see what you have selected. You can then use the sliders to adjust the selection area. Make sure Preview is checked so you can see the results of your changes.
Radius controls the size of the area inside the selection boundary where the edge refinement occurs. The higher the number the more contracted from the original selection area. Contrast sharpens the edges of the selection. The higher the Contrast number the more defined the edges will be. Smooth controls irregularities in the selection boundary. The higher the number, the more smoothed out the selection boundary will be. Feathering the selection will create a faded transition from the selected area to the area outside the selection. The higher the number, the larger the feathered area will be up to 250 pixels. Contract/Expand enlarges or minimizes the selection boundary. Positive numbers expand and negative numbers contract. This tool in conjunction with others can help fix problems in your selection boundary. For example, if some of the background is still visible around the edge of your selection, contract the boundary. Below the sliders are five options that allow you to adjust how your selection is previewed with descriptions below that describe each option.