Use magnifier tool in Preview to examine fine print in document

use-manifier-tool-in-preview

Preview in OS X comes with a Magnifier tool that lets you zoom in and get a closer look at the fine print of a document. Select from menu Tools > Show Magnifier to display the zoom tool on the screen, or use the shortcut key ` that is located under Esc. Pinch to increase or decrease the zoom of the magnifier.