• Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint
Share this Page URL
Help

Chapter 21. Output > PostScript and Image Resolution

PostScript and Image Resolution

It's almost impossible to talk about PostScript rendering of images without talking about image resolution. Many readers have written to me in past years asking me what the input should be for a particular image, and I always have to respond with a question: What is your intended output for the file? It makes very little sense to choose an input resolution without first knowing whether the image is going to press, going up on the fridge, or going across the World Wide Web. Let's take a brief look at PostScript technology, and then get involved with resolution—both its meaning and how to calculate it.

PostScript as a Halftone Dot Shaper

Using PostScript to render a continuous tone image, you can expect the most faithful of halftone renderings possible today. Other printing technologies put different-sized dots on a page, but they are not organized in screen lines that pressmen use. In Figure 21.5, on the left is a (nearly <g>) continuous tone image of a duck. On the right is a PostScript halftone rendering of the same image. I've used only 30 dots per inch (dpi) on the PostScript duck, which is a foolishly low resolution, but it helps display the individual dots better. Can you see how every tone on the left duck has corresponding-sized dots that, together, represent the continuous tones?


PREVIEW

                                                                          

Not a subscriber?

Start A Free Trial


  
  • Creative Edge
  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint