Working with Selections

Selections are especially important in Photoshop due to the pixel-based nature of the program. With the exception of text and vector shapes, everything in Photoshop is just a mass of pixels. If you have a photograph with a blue sky, don't think of it as a sky that's colored blue, but rather many, many blue pixels that together form the image of a sky. If you want to change the sky to a different color, you can't just select the sky; you have to select all the individual pixels that form the sky. At a basic level, if you want to manipulate only part of your image, you need to isolate that part so that other parts of your image aren't affected (see Figure 5.11).

Figure 5.11. A file with one area of the image selected.

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Selections can also be called masks. When professionals used an airbrush to edit photographs in the past, they didn't want to accidentally affect other parts of the photo as they worked, so they cut masks (called friskets) that allowed them to use the airbrush on a specific part of the photo.

It might all sound a bit confusing, but as we go through the individual selection tools and the methods used to work with selections, everything will begin to make sense.

Marquee Selection Tools

In the basic introduction to making selections back in Chapter 4, we discussed the Marquee selection tools. These are used whenever you want to select a rectangular or elliptical range of pixels. For example, say that you want to darken a rectangu-lar area of a photo so that you can overlay some text. You would use the Rectangular Marquee tool to select an area that you will darken.

You have various options when using the Marquee tools:

• Holding the Shift key while dragging constrains the marquee area to a square or a circle.

• Holding the Option (Alt) key while dragging draws the marquee out from the center of where you clicked rather than from the corner of where you clicked.

• Holding the spacebar "freezes" the marquee and lets you position it anywhere in your image.

The options for the Marquee tool can be found in the Tool Options bar. By default, if you currently have a selection on your screen and then you draw a new marquee, you get a new selection and the previous marquee is discarded. You can change this behavior by choosing from the options Add, Subtract, or Intersect (see Figure 5.12). For example, if you draw your first selection, then click on the Add button, and then draw another marquee, both areas will become selected simultaneously. If your new marquee overlaps the previous one, they will be joined together to form a single larger selection.

Figure 5.12. Choosing marquee options from the Tool Options bar.

Did you Know?

I personally find it tedious to have to navigate up to the Tool Options bar to specify Add, Subtract, or Intersect mode, so naturally, I use the keyboard shortcuts. Holding the Shift key adds to your selection, holding Option (Alt) subtracts from your selection, and holding both Shift and Option (Alt) together uses the intersect mode.

Notice that the Marquee icon in the Tool Options bar is actually a pop-up menu button in itself. See the sidebar "Tool Options for Everyone," later in this section.

At times you might want to draw a marquee that is a specific size. Rather than guessing as you draw the marquee, you can choose one of the options from the Style pop-up menu in the Tool Options bar: Fixed Aspect Ratio (which resamples the file) or Fixed Size (see Figure 5.13). When either of these two options is chosen, you can enter a Width and Height value, and you'll notice that as you draw with the Marquee tool, your selection will be created or constrained to the dimensions you've specified.

Figure 5.13. Choosing the Fixed Size setting in the Tool Options bar.

After you've drawn your selection, you can move the selection around as you like by positioning your cursor anywhere inside the marquee and then dragging it. You'll notice that only the selection itself moves, not the pixels that are inside it. To move the pixels, switch to the Move tool or press and hold the Command (Ctrl) key before you start dragging the selection. To drag a copy of the selected pixels, press and hold the Command (Ctrl) and the Option (Alt) keys before you click and drag.

Lasso Tools

Although the Marquee selection tools can be quite helpful, chances are, there will be plenty of times when you'll need to select something that isn't rectangular or elliptical in shape. The Lasso tool enables you to make irregularly shaped selections.

Simply choose the Lasso tool and press the mouse button. As you drag, you'll see a line appear. When you release the mouse button, Photoshop closes the path and turns it into a selection (see Figure 5.14). All the options we spoke about for the Marquee tools (adding, subtracting, moving, and so on) are available here as well.

Figure 5.14. A selection created with the Lasso tool.

If you're not as comfortable using a mouse, it can be difficult to make clean selections using the Lasso tool. Don't fret, thoughPhotoshop has two variations of the Lasso tool that might help:

• Polygonal Lasso tool I personally use this selection tool more than any other, and I find it extremely useful for many tasks, including creating silhouettes (which we discuss later in the chapter). Instead of having to press the mouse and drag it all over your screen, you can click once and then move your cursor to the next spot and click again. A "rubber band" follows your cursor around to give you visual feedback of where your selection path will be drawn (see Figure 5.15). You can either click on the original point to close your path and turn it into a selection or simply double-click to have Photoshop automatically close the path for you.

  Figure 5.15. Making a selection using the Polygonal Lasso tool.

  
  
  

  Did you Know?

  Holding the Option (Alt) key while using the regular Lasso tool makes it act just like the Polygonal Lasso tool.

  
  

• Magnetic Lasso tool You spent enough money on your computer and on the software you're using, so why are you left doing all the work? Shouldn't the computer be doing the work for you? Well, the Magnetic Lasso tool does its part: It automatically detects edges as you use it. An edge here is defined as a shift or change between one color and another. As you drag along an edge with the Magnetic Lasso tool, it automatically detects the edge and draws a path along it (see Figure 5.16). Double-clicking with the tool automatically closes the path and turns it into an active selection.

  Figure 5.16. Making a selection using the Magnetic Lasso tool.

  
  
  

If you look at the Tool Options bar when you have the Magnetic Lasso tool selected, you can see various options that control the sensitivity of the tool (see Figure 5.17). Width refers to how far the tool will look for an edge from where your cursor is. Edge Contrast controls how sensitive the tool is with regard to differences in color. A higher number finds only an edge that is a high-contrast one, whereas a lower number looks for more subtle shifts in color. The Frequency value determines how many points the tool uses to draw out the path. A higher number yields a path that is more precise, and a lower number results in a smoother path. The button at the far right enables you to use a pressure-sensitive tablet to change the width.

Figure 5.17. The settings for the Magnetic Lasso tool.

Did you Know?

With Caps Lock turned on, Photoshop displays the cursor for the Magnetic Lasso tool as the size of the Width setting, making it easier to trace over edges of color. Pressing the right or left brackets on your keyboard increases or decreases the Width setting by 1 pixel.

Magic Wand

For selecting areas of similar color, you can use the Magic Wand tool. By default, the Magic Wand selects all pixels of similar color adjacent to the area that you click on. Simply click on an area of your image. If you uncheck the Contiguous option in the Tool Options bar, Photoshop will select all similarly colored pixels throughout the entire document.

You can control how sensitive the Magic Wand tool is by adjusting the Tolerance setting in the Tool Options bar (see Figure 5.18). A low tolerance number means the Magic Wand will select only pixels that are closer to the color that you clicked on. For example, if you click on a dark blue color with a low tolerance, the Magic Wand will select only dark-blue pixelsbut with a higher tolerance, other shades of blue will be selected as well (see Figure 5.19).

Figure 5.18. The Tool Options bar for the Magic Wand tool.

Figure 5.19. A selection made with a high tolerance setting (left) and a selection made with a low tolerance setting (right).

Did you Know?

If you don't see the Tolerance setting in the Tool Options bar, it means you haven't selected the Magic Wand tool from the toolbox.

As with the other selection tools, you can use the Add, Subtract, and Intersect options with the Magic Wand tool.

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Another way to make a selection is by using a feature called Quick Mask, which we cover later in the chapter.

Selecting a Range of Colors

Although the Magic Wand tool is cool, it doesn't really provide the user (that's you) with any useful feedback. It's basically hit and missyou click, see what gets selected, deselect, change the tolerance level a bit, and then try again.

Let me direct your attention to the Color Range feature (Select, Color Range). Here you can use an eyedropper tool to click on parts of an image and get a preview so that you can see what will be selected before you actually make the selection (see Figure 5.20). Above that, you have options such as Fuzziness, which can control how sensitive the feature is to color shifts. Using the Select pop-up menu, you can choose to automatically select ranges of predefined colors, highlights, shadows, midtones, and even out-of-gamut colors (see Figure 5.21).

Figure 5.20. Using the Color Range dialog box.

Figure 5.21. Choosing from various selection options in the Color Range dialog box.

For even better previewing, you can choose to preview your document window itself with different viewing options that are found in the Selection Preview pop-up menu.

Clicking on the OK button closes the Color Range dialog box and returns you to your document, with your new selection waiting for you.

Feathering

Ever see a nice vignette photograph with a soft edge (see Figure 5.22) and wonder how they did that? Wonder no more. Until now, you've been creating selections that have hard edges. Using a technique called feathering, you can specify a gradual edge for your selection instead of a hard one. You can specify how soft your edges are by indicating how many pixels you want your feather to be. For each of the selection tools, you can specify a feather amount in the Tool Options bar. Doing so applies the feather to your selection as you make it. Alternatively, you can apply a feather by making a selection, choosing Select, Feather, and then entering a feather radius (see Figure 5.23).

Figure 5.22. A photograph with a vignette.

Figure 5.23. Choosing to specify a feather for your selection.

When you apply a feather to a selection, it stays until you discard the selection. Additionally, the feather isn't editable, meaning that you can't change the value. So if you apply a 5-pixel feather to a selection, you can't then decide to change it to an 8-pixel feather. You basically have to discard the selection, create a new one, and then apply an 8-pixel feather.

Did you Know?

When you're unsure how much of a feather you want, save your selection before you apply a feather (saving selections is covered later in this chapter). This way you can always reapply the feather, if necessary.

Here's an important fact: Feathers are calculated using pixels, not units that are absolute. Because the size of a pixel is dependent on the resolution of your file, a 10-pixel feather might be very soft in a 72ppi file, yet barely recognizable in a 300ppi file (see Figure 5.24). As you get experience in working with feathered selections, you'll get a better feel for how much is right for each file.

Figure 5.24. A 10-pixel feather in a 72dpi image (left) and a 300dpi image (right).

There are many uses for feathering selections. As we mentioned earlier, they can be used to help create soft-edged masks to create vignettes. They can also be used for creating soft cast shadows, for glow effects, for blending photos into each other, and more. I find that they are most useful for selections that you make for purposes of photo retouching. If you have an area that needs an adjustment such as a color shift, doing so with a regular selection creates a visible line that shows where you made the correction. Using a feathered selection, however, results in a seamless correction that no one will be able to see (see Figure 5.25).

Figure 5.25. The paint dab in the middle was adjusted in this photo. The image on the left had a feather applied to the selection before the retouching was done, and the image on the right did not.

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Tool Options for Everyone

The Tool Options bar is pretty handy and gives quick access to the most commonly used options for each Photoshop tool, but the most brilliant part of it is something called Tool Presets, which enable you to save different settings that you use often. For example, say you often use a feathered 4x5 aspect ratio setting for your Rectangular Marquee. You can save that as a tool preset and access those settings with one click of a button. You can store many of these tool presets, saving you valuable time as you work on your files.

Of course, these presets aren't limited to the selection toolsyou can save tool presets for just about any Photoshop tool. You do so by choosing the settings you want in the Tool Options bar, clicking on the tool icon (the one that looks like a pop-up button), and then clicking on the Create New Tool Preset button. Alternatively, you can choose New Tool Preset from the flyout menu (see Figure 5.26). Give your new tool preset a descriptive name (otherwise, you won't remember what each one is), and it will appear in the list from now on (these are application preferences, meaning that even if you close the file you're working on or open a new or different file, your tool presets will still be present).

Figure 5.26. Defining a new tool preset.

Modifying Selections

You can modify a selection after it's created in several ways. One of the most useful is by using the Select, Inverse command or pressing Command+Shift+I (Ctrl+Shift+I), which basically selects whatever you don't have selected (and deselects everything that was selected). Sometimes it's easier to select the one part of an image that you don't want and then invert your selection (see Figure 5.27). You can also transform your selection. These transformations that you make (by choosing Select, Transform Selection) apply only to the selection itself, not the pixels inside them. For example, you might use the Rectangular Marquee tool to create a square selection, and then use the Transform Selection command to rotate the square (see Figure 5.28) to effectively get a diamond-shape selection.

Figure 5.27. Choosing to invert your selection.

Figure 5.28. Transforming a selection.

Under the Select, Modify submenu, there are four additional ways you can adjust your selection. All of them are useful, and it would be a good idea to experiment with them to fully understand what each one does. In each of these cases, you'll lose your original selection, so you might want to save it before you modify the selection. These are the additional options:

• Border Use the Select, Modify, Border command to specify a pixel width for just the edge of your selection (see Figure 5.29), similar to adding a stroke. This command yields a round-cornered selection, which is not appropriate in all cases.

  Figure 5.29. A selection with the Border modification applied to it.

  
  
  

• Smooth Not everyone can draw with a mouse as well as they can with a pencil (myself included), so when you're creating selections with the Lasso tools, it's nice to know that you can smooth out your selections by choosing Select, Modify, Smooth. This is also useful when you're making selections with the Magic Wand tool because it can sometimes create selections with jagged or uneven edges.

• Expand At times you will want to enlarge or expand your selection by a specific number of pixels. One such example is if you want to have a border or background around the edges of text. Although you can instead scale your selections using the Transform Selection command I mentioned earlier, many times simply scaling your selection won't work (especially with odd-shape selections).

• Contract Rather than expanding your selections, sometimes you'll want to contract them. You can do so by choosing Select, Modify, Contract and then specifying the number of pixels you want your selection to shrink.

Saving and Loading Selections

A quick selection is easy enough to make, but many times getting just the perfect selection for your needs can take quite a bit of time (and a double dose of patience). The last thing you want in that case is to accidentally click somewhere and lose your selection. Or you might want to continue to make adjustments to that selection later. You can save your selections so that you can retrieve them later by choosing Select, Save Selection (see Figure 5.30). It's best to give your selections a descriptive name; otherwise, if you have several of them, it might be difficult to find the right one when you want to load one.

Figure 5.30. Choosing to save your selection.

Did you Know?

If you want to access the last selection you made, choose Select, Reselect.

In general, it's a good idea to name things carefully because one day you'll have to edit the file, and you'll go crazy trying to remember what you named it. You also never know who else will be working with your file (a co-worker, prepress operator, or client, for example), so naming things that will help people quickly find what they are looking for is important.

When you have selections already saved in a file, you can either continue to save new selections or add to or modify existing selections (see Figure 5.31). You'll probably get a much better understanding of how selections work when you learn what channels are. Oh, look at thatthe next section is about channels!

Figure 5.31. Choosing to modify an existing selection.

Channels

Also called alpha channels, channels can be thought of as selections because, in reality, that's what they are. You can find them in the Channels palette.

Every file has at least one channel by default, and three or more if it is a color file. For example, an RGB file starts with three channels: one each for red, green, and blue. Photoshop also displays a composite, one for all of the channels combined, although this composite isn't actually a channel itself (see Figure 5.32). You can view and edit each channel individually, giving you total control over your image.

Figure 5.32. The channels of an RGB document.

But the real strength here is that you can create your own channels. When you save a selection (as mentioned earlier), Photoshop is creating a channel, and that is how the selection is stored (see Figure 5.33). Channels that you create can contain 256 levels of gray. Certain file formats can use the information in channels as well. For example, you can specify that a channel should be a transparency mask when you export a file as a PNG from Photoshop. In contrast to clipping masks (which we discuss later in the chapter) that you might save in EPS format, an alpha channel transparency mask can utilize 256 levels of gray.

Figure 5.33. A file with several channels saved.

Rather than having to load selections via the Select menu, you can simply Command+click (Ctrl+click) on a channel (in the Channels palette) to load that selection. This is true with any layer, actuallyyou can create a selection based on all of a layer's contents this way.

Paths

If you've used Illustrator before, you know what a Bézier path is. You'll learn more about it in Chapter 7, "Using Adobe Illustrator CS2," but at a basic level, it's an object-based path that you can draw using the Pen tool (see Figure 5.34). It just so happens that Illustrator, InDesign, and Photoshop all have Bézier Pen toolsmainly because these tools are basic drawing tools.

Figure 5.34. Drawing a Bézier path with the Pen tool.

The selection tools we've discussed until now aren't really precise drawing tools at all. When you want to draw a high-quality selection, the Pen tool is the way to go. You can also use a variety of vector shape tools to create paths, including the Rectangle and Ellipse tools. When you select one of these Shape tools, you need to be aware of three options in the Tool Options bar that control the behavior of the paths you draw. The Shape Layers option creates vector layer masks (covered later in this chapter), the Paths option creates free-standing vector paths, and the Fill Pixels options (not available for the Pen tools) immediately commits paths to pixels as you draw (see Figure 5.35). For making selections, the Paths option will give you the results that you expect.

Figure 5.35. Choosing the Paths option for drawing with the Rectangle tool.

As you draw a path, you'll see it appear in the Paths palette. From the Paths palette, you can choose Save Path from the palette flyout menu to save the path for future use. At any time you can also Command+click (Ctrl+click) on the path in the Paths palette to create an active selection from the path.

You can also use paths in the reverse context. You start by creating a selection using any of the methods we've discussed. Then, with the selection active, choose Make Work Path from the Paths palette flyout menu (see Figure 5.36) to turn that selection into a vector path; at that point, you can use the Pen tools to further edit that path, if necessary.

Figure 5.36. Creating a work path from a selection.

Creating a Clipping Path

A clipping path is basically a mask for an exported EPS image (although the newer TIFF format supports clipping paths as well). You can save a path with an image that will define how the image appears in a page-layout application, such as InDesign or QuarkXPress (see Figure 5.37).

Figure 5.37. An image as it appears placed in InDesign, with (left) and without (right) a Photoshop clipping path applied.

Back in Chapter 3, "The Game Plan: Developing a Workflow," we discussed how InDesign can understand Photoshop's native transparency, so clipping paths aren't really necessary in a full Adobe workflow. Regardless, it's important to know about clipping paths in case you need to work with QuarkXPress or send files to other people.

Begin by creating a path. If you're uncomfortable using the Pen tool, use the reverse method mentioned earlier, in which you start with a selection and then convert it to a path. After the path is created, save it. Then choose Clipping Path from the Paths palette flyout menu and choose the path you saved. I normally use 2 for my flatness setting (see Figure 5.38).

Figure 5.38. Specifying clipping path settings.

Finally, for the path to be recognized in a page-layout application, choose to save your file in either Photoshop EPS or TIFF format. See the discussion later in this chapter for information on how to save files.