Selection Tool Tutorial

Using Photoshop's Lasso, Polygonal, Magic Wand & Marquee Selection Tools

Selection Tool Tutorial

Photoshop Filter and Tool Tutorials

Curves | Color Balance | Channels | White-Point | Burn & Dodge | Color Picker | Clone Stamp | Noise Filter

All Tutorial Text & Images - Copyright © 2011 KHI, Inc.

Using Photoshop's Lasso & Polygonal Lasso Tool Selection Tool

This Photoshop tutorial is designed to instruct in the use of Photoshop's Selection Tool suite used to copy-and-paste, or drag and drop a selection into a new layer. This arsenal of selection tools is used to define an area to be painted, erased, filtered or retouched, then blending and merging this modified area into the surrounding area or background layer.

There are five methods for selecting an area: the Lasso Tool (L), the Polygonal Lasso Tool (L), the Magnetic Lasso Tool (also L), the Magic Wand Tool (W) and the Marquee Selection Tool (M) which contains the Rectangular Marquee, Elliptical Marquee, Single Row Marquee and Single Column Marquee Tool iterations. You can also make a selection of any pixel date on a given layer by using the Command>A "select all" keyboard command. Even though the "select all" command will create a selection of the entire art-board window, you can force the marching ants to constrain around to pixel data by nudging the selection by one increment by using Command>V and the arrow keys. The you nudge it back by one increment and it is back to its original position. You can also Command>Click on a specific layer in the Layers palette to create a constrained selection of the pixel data.

Cloning Objects with the Selection Tool

Rather that using Photoshop's clumsy Clone Stamp Tool which can have a noticeably obvious stepping-effect, a more effective way is to "clone" an object is by selecting, pasting, and blending the object on its own layer. This will have a significantly more realistic result than with the clone tool, and it is infinitely adjustable, editable, and reversible.

In this tutorial we will retouch or remove all of the people from the original photograph's background. To accomplish this task we will need a photograph of the grass area taken from another angle. If that photo also contains unwanted elements, we will use the Selection Tool to remove them.

Photoshop Photo Composition Sample

To retouch out the unwanted objects we you would draw a selection of a small area of grass, making the selection as random and rough as possible. The jagged edge of the selection will disguise any obvious cloned edge. Use the 'Feather' command (Select>Feather) to soften the selection by 1 pixel. Now drag the selected area while holding the Option and Command keys simultaneously (this will create a double cursor). Continue the process, making selections from a variety of areas so that there is not too much repetition.

If you are moving a selection from a foreground area (lower in the photo) to an area that is further away (higher in the photo) you must also scale its size down to match the surrounding image. You can accomplish this by using Photoshop's Free Transform tool (Command>T).

Cloning with the Selection Tool

Once our lawn area is totally free of any unwanted objects, we will make any necessary color corrections so that the new background matches the old one. To do this we will use Photoshop's Curves, and Color Balance tools.

Tracing with the Selection Tool

The first step in assembling our final image is to 'Command>Shift' click the Background layer in the Photoshop Layers palette, or use 'Command>A' to "select all." Copy the Background layer, and past to a new layer.

The second step will be to copy and past your separate lawn photo into a new layer, and place that layer underneath the copy of the Background layer you created in step 1 above. Now you will use the 'Polygonal Lasso Tool (L)' to carefully draw around the foreground motorcycle.

Zooming with the Selection Tool

You can zoom in a couple of hundred percent to make an accurate tracing. To zoom in while in the Polygonal Lasso Tool mode, simply press the Command and Shift keys. This will change the cursor into a 'plus' magnifying glass. To zoom out while in the Polygonal Lasso Tool mode you would simultaneously press the Option, Command, and Shift keys which will change the cursor into a 'minus' magnifying glass.

Technical Note: You can use the standard Lasso Tool (L) in the same way as the Polygonal Lasso Tool (L) by simply holding the Option key while you are clicking point-to-point. At any time during your first past you can drag your pen in the same way as you would for the Lasso Tool. Once you release the selection the tool function reverts to the Lasso Tool, and does not have Polygonal Lasso Tool functions. The zoom function does not work while you are in the standard Lasso Tool mode.

Photoshop Photo Composition Layers

When you are finished with the selection you can use the Selection Tool's 'Smooth' function (Select>Modify>Smooth) to smooth out any rough edges. Now comes the most important step - using the 'Feather' command (Select>Feather) to soften the selection by 1 pixel. Now use the Select>Inverse command in the menu-bar to reverse the selection. Everything but the foreground object should now be selected.

Once your selection is made, make sure you are working on the top layer containing the original background with the people, and erase away the unwanted background. This will reveal the desired lawn area on the lower layer.

Replacing a Photo's Background

You can use the same technique to replace the existing background in your photo with an entirely new background from a different photograph. However, to pull this off, it is important to keep several things consistent. The lighting (time of day) and direction of the sunlight should be the same, and the lens you use should also be the same. In addition, the perspective and location of the horizon must match. In the example below, the horizon line in relation to the car is the same even though the car has been reoriented and relocated to a lower position in the photo.

Before & After Replacing Photo Background with Photoshop

Focus (depth-of-field) should also be consistent, so if the background is out of focus in your main photo you should make sure the same f-stop is used in your secondary photo.

Technical Note: Don't bother with auto-tracing functions, or the 'Magic Wand Tool (W)' to do the work for you. These tools never produce a good result, especially if your foreground object has similar tonal value to the background you are separating it from. It may take time and patience, but the end result will be realistic and convincing.

Note: The following hardware and software was used in this tutorial: An Apple Mac Pro desktop computer, a Wacom Intuos 6x8 drawing tablet, Adobe Photoshop CS-CS5 photo editing software and a properly calibrated monitor.

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