Color Picker Dialog Box
The Color Picker dialog box is available in many areas of Photoshop. The easiest way to get to it is to click your foreground or background color. There are many choices in this dialog box because there are many different ways to define a color. In this section, we'll cover all the various ways you can choose a color. I'll start off by showing you how to preview the color you're selecting.
Previewing a Color
While you're choosing a color, you can glance at the two color swatches to the right of the vertical gradient to compare the color you've chosen (the top swatch) to the color you had previously (the bottom swatch).
Be sure to watch for the out-of-gamut warning, which is indicated by a small triangle that appears next to these color swatches (Figure 1.21). This triangle warns you that the color you have chosen is not reproducible in CMYK mode, which means that it cannot be printed without shifting to a slightly different color. Fortunately, Photoshop provides you with a preview of what the color would have to shift to in order to be printable. You can find this preview in the small color swatch that appears directly below the triangle icon, and you can select this printable color by clicking the color swatch. Or, you can have Photoshop show you what all the colors would look like when printed by choosing View > Proof Colors while the Color Picker dialog box is open. That will change the look of every color that appears in the picker, but you will still have to click that little triangle symbol, because that's just a preview—it doesn't actually change the colors you're choosing.
Figure 1.21. The warning triangle indicates a color that is not reproducible in CMYK mode. The cube symbol indicates that a color is not a web-safe color and might appear dithered in a web browser.
Choosing Web-Safe Colors
There is a set of special colors, known as web-safe colors, that are used for large areas of solid color on a web site. By using a web-safe color, you will prevent those areas from becoming dithered when viewed on a low-end computer (that is, simulated by using a pattern of two solid colors; for example, adding a pattern of red dots to a yellow area to create orange). So, if you are choosing a color that will be used in a large area on a web page, look for the Color Cube symbol (Figure 1.21). Web-safe colors are also known as colors that are within the color cube—that's why Adobe used a cube symbol for this feature. When you click the cube symbol, the color you have chosen will shift a little to become a web-safe color.
Selecting with the Color Field
Usually, the simplest method for choosing a color is to eyeball it. In the Color Picker dialog box, you can click in the vertical gradient to select the general color you want to use. Then click and drag around the large square area at the left to choose a shade of that color.
Selecting by Hue, Saturation, and Brightness
You can also change what appears in the vertical gradient by clicking any of the radio buttons on the right side of the dialog box (Figures 1.22 to 1.24). In this dialog box, H = Hue, S = Saturation, and B = Brightness. You can use the numbers at the right of the dialog box to describe the color you've chosen. (This can be a big help when you're describing a color to someone on the phone.) So, if you know the exact color you need, just type its exact numbers into that area.
Figure 1.22. Hue.
Figure 1.23. Saturation.
Figure 1.24. Brightness.
Selecting from a Color Library
If you want to pick your colors from a color library (PANTONE, TruMatch, and so on), click the Color Libraries button (Custom button in CS). This will bring up the Color Libraries dialog box (Figure 1.25). Choose the color library you want to use from the pop-up menu at the top of the dialog box, then scroll through the list to find the color you desire. You can also type in numbers to select a specific color (I know, there isn't the usual text field to enter them in, but just start typing), but make sure you type really fast. I'm not sure why it works this way, but this part of Photoshop gets impatient with slow typists. For example, if you slowly type the number 356, Photoshop might jump to a color number starting with 3 and then go to one that starts with 5. This is sort of annoying, but it shouldn't pose a problem as long as you type the number quickly. (You can purchase various color library swatch books at an art supply store.)
Figure 1.25. The Custom Color Picker.
 | Although the Color Libraries are great for users printing with CMYK inks, it's not so hot for those using true spot colors (metallic, fluorescent, and other colors that cannot be reproduced using CMYK inks). If you're going to be using true spot colors, see Bonus Chapter 2, “Channels” on the CD. |