All About PDF Files

Why do I need to explain PDF files? Everybody knows what a PDF file is. You download Adobe Reader and you get to open a PDF file. But how did it get to be in the PDF format? What exactly is it? It’s worth taking a few minutes to understand what a PDF file is and how it’s created. Then next week, we’ll discuss when and how you can edit a PDF file and when PDFs are helpful to designers, and when they’re not.

What to do?

Say you create a beautiful file in Microsoft PowerPoint, and you want your friend to see it. But your friend doesn’t have PowerPoint, or has an older version. You can take a screen shot and send that to your friend. Or you can print it out and give it to your friend. Or you can create a PDF file, and your friend can read it in Adobe Reader.

When you have a file on your computer, you can click the print button, and your computer sends code to the printer to tell the printed page how to look. You may have told it to print portrait or landscape, make it smaller or larger, print in color or black and white, high or low quality. Your printer interprets the code and renders a picture on the page that looks like what’s on your screen, based on the options that you chose in your print menu. Your printer understands what font to use, what images look like and how the page should be laid out.

PDF Files

Adobe Acrobat is the paid program that creates PDF files. Acrobat uses the code that would be sent to the printer and renders it in a file, instead of rendering it on a piece of paper. So Acrobat interprets the code instead of a printer, and creates a file with the extension of PDF (Portable Document Format.) Now the file can be viewed in Adobe Acrobat on your computer without having to have the program that created it.

And Adobe released Adobe Reader as a free program that would interpret the PDF format and allow you to view the PDF file if you didn’t have Adobe Acrobat.

So, Adobe Acrobat is the paid program that creates PDF files. Adobe (Acrobat) Reader is the free and widely available program that readers PDF files.

Back in the day, wherever you saw a link to a PDF file, you also saw a link to the “download Adobe Reader for free” link. Nowadays, PDF files can be read in browsers, and Adobe Reader comes preinstalled on most operating systems. Many programs even come with built-in options to print or to “save as” a PDF file, even if you don’t have Adobe Acrobat installed on your computer.

Of course, now, a bazillion versions later, PDF files are so much more than they were when they were first created. Now they can be edited, linked and embedded with video. You can fill them out, password-protect them and electronically sign them.

Why did you need to know all this? In another article, we’ll explain how and why and when you can edit a PDF file. We’ll also explain when a PDF file is scalable to any size, and when it’s not. When it can be used by a commercial printer, and when it can’t.