Sizing Digital Images in Adobe Photoshop CS4
Once you’ve acquired your digital images, you’ll need to size them for your project (as well as ultimate output). For many Photoshop users, such as photographers, this may be as straightforward as cropping and sizing. This chapter explores several techniques for sizing your images. You’ll learn about the concept of resampling, which addresses how the computer adds or subtracts information from a digital image while trying to retain detail and clarity.
Chapter 3 looked closely at the process of acquiring digital images. If you skipped ahead or just skimmed that chapter, go back—a solid understanding of those concepts is required. Quite simply, you must know the capabilities of your scanner or digital camera to process information.
This photo was scanned at two different resolutions. The image on the left was scanned at 300 spi, and the image on the right was scanned at 72 spi. Examine the detailed enlargements to see the impact of different scanner settings.
Previous chapters also briefly discussed output requirements for different formats. The second part of the image-sizing puzzle is a clear understanding of these output requirements. What resolution does your printer need? Are you sending the image to a service provider such as a developer or commercial printer? You’ll need to make lots of choices, but they should be based on where the image needs to end up. Do not make assumptions when starting a project. Know the destination of your image so you’ll know which path to take.