Q: So how does it work?

A: Well, if you’ve been using computers for long enough, you might remember the days when a word processor was just that; you could write text with it, and nothing more. Illustrations were drawn using a vector graphics program and it was all put together using DTP software.

But with the advent of GUIs, word processors started getting graphics functions, desktop publishers started getting better text editing tools and the overlap between the various applications has been very significant for decades.

Despite this, each program uses a different internal model and you can’t just open a Word document in InDesign to make fine typographical adjustments, as they are not even supported in Word’s model.

So, the first part of Editable PDF is to standardize these models; instead of a Word text box, an InDesign text frame and a Scribus text frame, you have a standard Editable PDF text frame which is fully specified and documented, just like PDF is today.

The second key component of Editable PDF is its robust typography.

As I mentioned above, technical issues between platforms can cause text to reflow differently, causing major changes in the layout. PDF, on the other hand, stores the position of each character and each line break explicitly, making it possible to average out any differences in character width across the whole line when editing the text on a different platform.

Furthermore, if a font is completely missing, PDF has a mechanism to synthesize a replacement font with exactly the same metrics, which enables non-destructive editing. This means that even documents using licensed fonts, such as most corporate fonts, can be shared with collaborators outside of the organization; they will simply see a different font, but everything will still fit the same way as before.