What makes a Mac a Mac?  Some would say it’s Apple’s stunning industrial design - copied but seldom (if ever) equaled.  Others would site the Mac’s tight integration between software and hardware.  Still others would claim that the Mac’s “standard equipment” iLife ’08 suite (digital lifestyle applications iTunes, iPhoto, iMovie, iDVD, iWeb, and GarageBand) sets it apart from run-of-the-mill PCs.  I suggest the bedrock of the Mac experience and what defines it is Mac OS X “Leopard” (singled out by Ed Mendelson of PC Magazine as “by far the best operating system ever written for the vast majority of consumers”).

This week I rise to sing the praises of an unsung hero of the Leopard operating system.  It’s one of many helper applications that come standard with Leopard that have “secret powers” that many users never encounter.  Our purpose today is to spotlight the strengths of one such application, called “Preview”.

From the name, one might think you would use Preview to take a preliminary look at the contents of a file.  And you’d be right.  But Preview can take you much deeper inside many different file formats.

For one, Preview is Mac OS X’s default viewer of PDF (Portable Document Format) files.  The PDF file format, created by Adobe, has been around since 1993.  It’s become the defacto standard for creating, distributing, and displaying digital documents.

PDF files are perfect for today’s Internet-delivered digital world because they are appear as the author intended when viewed on any computer, regardless of the operating system installed.  How do they do that (you seemed to ask)?  Each PDF file encapsulates (carries with it) a complete description of the document, including the text, fonts, and images that compose the document.  So you don’t need to worry if someone trying to view a document exactly as you created it can’t because they don’t have a certain font installed on their computer.

OK.  Back to Preview.  Or, actually, back to before Preview.  Before Preview gained PDF capabilities, in order to view PDF files Mac users needed to download Adobe’s Acrobat Reader (today called just “Adobe Reader”).  While Adobe Reader was/is free, it is slower than Preview in opening and scrolling through large PDF documents, especially those filled with images.

Preview in Leopard gives you the ability to modify existing PDF documents.  You can rearrange the order of pages, drag and drop pages in from other open PDF documents, or drag in entire PDF documents.

You can also make annotations to documents, useful when adding comments or doing group editing.  Highlight (as if you used a yellow highlighter marker) text selections, strike through or underline lines of text.  Place an oval or rectangle around a section of the document to place emphasis or designate an area of interest.  Add a “sticky note” to the document containing comments.  When you’re done, select “Save” from the File menu and your edits are part of the document.  You can also easily attach a PDF document to an e-mail message through the File menu.  Finally, you can add Bookmarks to the Preview menu bar (like you would in your web browser) for favorite or frequently used documents to provide easy access in the future.

Preview can also open, edit, and save many types of image files, including JPEG, TIFF, GIF, PNG, and Photoshop files.  It can perform more advanced edits to photos that you can’t do in iPhoto, like extracting an image (called “Instant Alpha”) from a simple background like a clear blue sky, or using “Extract Using Shape” to extract part of an image from a busy multicolor background, like colorful wallpaper.