Tutorials

How To Use the Quick Selection Tool in Photoshop CS3 and Beyond

The most common way that I alter local areas of images is to use Layer Masks. However, in some images you need to control the area of alteration more accurately than can easily be done with Layer Masks. In these situations it is better to use selections. By using selections, you can control more precisely the part of the image that is altered. Once you make your selection, you can use Layer/Adjustments to alter only the selected part of the image. I used to cringe whenever I knew I had to make a selection prior to the introduction of Photoshop CS3. The selection tools were, how shall I say it politely, crummy. Color Range and the Unmagical Wand can sometimes be used if one has to select something like blue sky. Otherwise, good luck with the Magnetic Lasso. However, all that changed with the introduction of the Quick Selection tool in Photoshop CS3. The selection below is difficult because of the close color matches of the duck and water in various places, but this new tool really has surprised me with its power. I still much prefer to use Layer Masks for most of my local changes to images, but sometimes there is no substitute for a good selection. Here's how to do it.

Photoshop Quick Selection Tool Choose the Quick Selection tool by clicking on its icon in the Toolbar folder. If the UnMagic Wand tool icon is showing, make sure you click in the lower right corner if the icon as shown to reveal the Quick Selection tool icon. Anytime you see that black triangle in the lower right corner of a toolbar icon, it means there are more tools that can be revealed by clicking the triangle. If the Auto-Enhance box is checked, the resulting selection will be smoother. Your subject matter will determine which choice works best. Experiment with both settings. A brush with a hard edge should be chosen. Hold the shift key down and hit the ] key 4 times. This will create the hardest edge possible regardless of the previous setting. Increse the brush size by clicking the ] key; reduce the size by clicking the [ key. The brush size should be as small as possible.

After your brush is adjusted, paint just inside the object all the way around (like the green brush outline below). At this point the duck below is not selected very accurately, as can be seen by the dotted lines. To clean this up, press the alt key and drag just outside the areas where the selection is not good (see the red brush strokes below). This will usually result in a fairly good selection. Magnify the image more, and continue to touch up the selection by painting inside the object to add to the selection, and outside the object with the alt key held down to subtract from the selection. At this point there is one area of water still in the selection, which is formed by the duck's head feathers and back. To eliminate this area, press the alt key and paint the inside of the area to subtract it from the selection.
Photoshop Quick Selection Tool

If you are having trouble getting a clean selection as described above, you can try the Refine Edges dialog box. Click on the Refine Edges button in the toolbar menu, just above the photograph. If the edges of your selection are not very distinct, you should try increasing the radius and contrast. I have found that the default Smoothness setting of 3 works well for me when I use Auto-Enhance, but if you need more smoothing, you can increase this value as well.
Most of the time you will not need to use the adjustments in the Refine Edges dialog box. The exception is Feather, which creates a gradual transition between the selection and the surrounding pixels. You should add feathering for every selection. The amount of feathering that you use will depend on the image, as well as the number of pixels in the image. I used a value of about 10-20 pixels for most of my images, which have 21-39 megapixels. For 10 megapixel cameras or less, you can try 3-5 pixels. You can see the effect of feathering by adjusting the feather slider. If you only want to adjust the selected area of the image, but not the area outside the selection, go ahead and set the Feather slider where you want it now. However, if you want to adjust the selected area one way and the nonselected area another way, adjust the Feather slider to 0, so that you can add the feathering separately later for the selected and nonselected area. This is because the feathing will be in the wrong direction for the nonselected area if you feather it now. This will become clearer as you work through the process.

Photoshop Quick Selection ToolOnce you have finished your selection, it should be saved. There are 2 ways to do this. You can go to the Menu bar and choose Selection/Save Selection. Or, you can go to the Menu bar and choose Window/Channels to pull up the Channels palette. Clicking on the second icon from the left at the bottom of the Channels palette (see red arrow) will save the selection as a channel. Either method saves the selection as a channel.
If your selection is still not as accurate as you would like it, you can clean it up by painting on the channel mask. This was almost always required for selections made without the Quick Selection tool. Painting whlte on the mask will add to the selection, while painting black will subtract from the selection. Hit the "B" key to select the brush, and the "D" key to set the background color to white and foreground color to black. The brush will paint with the foreground color, so set it to black or white as desired. The foreground and background colors can be inverted by hitting the "X" key. We'll discuss the use of the brush on masks in more detail in a future tutorial on Layer Masks. Oh, one more thing: you cannot paint on a mask that has an active selection. To delete the selection, hit control + D keys. But make sure you saved the selection first! If you forgot to save it, don't panic, just use the History palette (Window/History in the Menu bar) to undo it.
OK, now we're all set to use our new selection. You can load selections two ways. You do it from the Menu bar (Select/Load Selection), or by holding down the control key and clicking in the rectangular box in the Channels palette that is to the left of the name of your channel mask. In the example above, you would control + click in the rectangle next to "Alpha 1." By the way, Alpha 1 is the default name given to these masks. To change the name, double click on the name and enter any name you like. These channels are often referred to as "Alpha Channels," hence the name given by Photoshop.
Once the selection is loaded, it should be feathered. From the Menu bar choose Select/Modify/Feather and enter the number of pixels based on our earlier discussion above. Then you are free to modify the selection as desired by going to the Menu bar and choosing Layer/New Adjustment Layer/Whatever You Want. "Whatever You Want" can be any of the choices in the submenu, such as Brightness/Contrast (not a good one), Levels, Curves, Exposure, Vibrance, etc.
In the photo above, I wanted to make certain changes to the duck (levels, curves, unsharp mask) that I didn't want to apply to the water. However, I often want to adjust the water in different ways from the duck. How can we do that? Control + click the Alpha Channel rectangle as before to load the selection of the duck. Then go to the Menu bar and choose Select/Inverse (or use the keyboard shortcut control + shift+ I). Now everything but the duck is selected. Feather the selection by going to the Menu bar and choosing Select/Modify/Feather and enter the desired number of pixels. Now you can change the water at will without changing the duck.