Chapter 4. Pixel Basics

In this chapter you’ll learn how to change an image’s overall dimensions or resolution; sharpen the image afterward; change an image’s canvas size; crop an image; flip an image; and rotate an image.

Note: Changing an image’s dimensions in Photoshop while preserving its current resolution (leaving the Resample Image box checked) causes resampling, which degrades image quality. That’s why it’s always best to scan or create an image at or close to the desired output size. If you have to resample, apply the Unsharp Mask filter afterward to resharpen (see pages 84–85).

Changing dimensions and resolution

To change an image’s pixel dimensions for onscreen output:

  1. Choose Image > Image Size.

  2. Make sure Resample Image is checked , and ...

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