Chapter 3: Messing with Mode Matters

In This Chapter

  • Editing pixels in bitmap images
  • Understanding Photoshop image modes
  • Working in black and white, RGB, or CMYK

Before diving in to Photoshop, you should first understand color modes and the importance of starting with the most optimum color settings. No matter if you're producing a black-and-white or full-color image, a website, or a video, it is important to consider your basic settings.

Working with Bitmap Images

You may wonder how images in Photoshop show subtle changes in color values. To create those smooth gradations from one color to the next, Photoshop takes advantage of pixels and anti-aliasing. Bitmap images (or raster images) are based on a grid of pixels. (See Figure 3-1.) The grid is smaller or larger depending on the resolution of your image. The number of pixels along the height and width of a bitmap image are the pixel dimensions of an image, measured in pixels per inch (ppi). The more pixels per inch, the more detail in the image.

Unlike vector graphics (mathematically created paths), bitmap images can't be scaled without losing detail. (Refer to Figure 3-2 for an example of a bitmap image and a vector graphic.) Generally, you should use bitmap images at or close to the size you need. If you resize a bitmap image, it can become jagged on the edges of sharp objects. On the other hand, you can scale vector graphics and edit them without degrading sharp edges.

Figure 3-1: You can see the grid that makes up the ...

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