Adjusting Brightness and Color in Photoshop CS4
This chapter is from the book
This chapter is from the book
This chapter is from the book
WHAT YOU’LL LEARN IN THIS HOUR:
- Evaluating Your Color Adjustment Needs
- Adjusting by Eye with Variations
- Making Other Adjustments
- Preserving the Original with Adjustment Layers
- Understanding Channels
- Making Spot Fixes
- Converting Color to Black and White
Messing around with color—and I do use the term “messing around” advisedly—is a little bit science, a little bit art. You can make some adjustments “by the numbers,” such as darkening an image’s darkest points so they’re true white, but others have to be made by eye. When it comes right down to it, color is really all in your head—and that’s a good thing. In this hour, we look mostly at ways to “fix” the color in your pictures, making it more lifelike and true to the original. Of course, you can use the same methods for more nefarious purposes; if you want to make the sky green and the grass purple, that’s well within your reach using Photoshop.
Photoshop includes a full set of tools for making color adjustments, located on the Image, Adjustments submenu (see Figure 5.1). Some of these terms, such as Brightness/Contrast, might be familiar to you; others might not. Don’t worry; you’ll learn about them all in this hour.
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Figure 5.1 The Adjustments submenu gives you all the tools you’ll need to produce a more (or less) true-to-life image.
Evaluating Your Color Adjustment Needs
Before you start to adjust color, you need to make sure the image uses the right color mode; to do that, you have to evaluate what kind of color the picture contains and how you’ll eventually use the image. You learned about color models and color modes in the last hour, so you know that RGB mode is the way color is displayed on computer screens, and CMYK mode is the way color is printed. Because image colors can shift when you switch from one mode to another, it makes sense to adjust the color in a picture according to the way it will be displayed. For a picture that’s going on a web page, you should work in RGB mode. If your picture will be printed on a four-color process commercial press, work in RGB to start with, but make your final adjustments (if any are needed) after you convert the image to CMYK mode. If you’ll be printing on a home/office inkjet printer, stick with RGB, even though your printer uses CMYK inks. The software drivers for desktop inkjet printers are designed to convert from RGB to CMYK internally. Other kinds of color printers, such as color lasers, work fine with CMYK mode. On the other hand, if the picture is destined to be output or displayed in grayscale, forget about trying to make the sky a perfect blue; change the color mode to Grayscale and make the brightness and contrast perfect instead. Just keep these few rules in mind, and you won’t go wrong. Table 5.1 helps you keep your options sorted out.
Table 5.1. Color Adjustment Matrix
|
Adjust Color In |
If Output Is |
|
RGB |
Computer screen, the Web, or inkjet printer |
|
RGB first, and then CMYK |
Process color printing |
|
Grayscale |
Black-and-white printing |