PDF was initially released over 23 years ago, it solved a very important problem. How could you provide an electronic equivalent to paper?
As a standard, like most things evolved over decades, it’s actually pretty awful. The specification reads like it was designed by an army of people who seldom spoke and had no long term plan.
That said, it is without a doubt still one of the most important file formats on the web. Its issues are a direct result of the era it was designed in, open standards were far from the norm, the desktop was king, and the internet was primarily used for email.
A lot has changed since then, but PDF itself, though it has had more features added to its specification, has not materially changed much. Some of the larger issues with the format include:
- They are often bloated large documents making them slow to download and render,
- The layout is generally fixed and not responsive making them awkward to read on a mobile device,
- They are often collapsed into images making text selection, data extraction and commenting difficult,
- Modern developer toolchains seldom have robust (if any) support for working with the format,
- Commercial toolkits are available for some languages but they seldom support all of the options in the format which are in common use,
- The specification is complex but there is no decent interopability test suite for implementations to target,
- The security protections offered by the format are generally poor, based on weak cryptographic constructions and in some cases rely on security by obscurity,
- The complexity of the format has lead to many vulnerabilities in the applications that support it.
Beyond that, user expectations have also changed when it comes to content consumption, gone are the days of glossy flyers describing products or services. Today the expectation is that you have rich interactive web content.
To me, that sounds like a pretty dire situation, if so why is it PDF is still so popular?
The main reason, beyond market share, is it solves a real problem that we still experience. That is, that it provides an interoperable digital format that approximates paper (and prints reliably).
While increasingly more business processes are being brought online, there will still be a need for paper forms, invoices and contracts for the foreseeable future.
Additionally in the case of forms, being able to have one form that works both electronically and physically has a lot of value.
Contracts and invoices on the other hand, often need to be enforced for years, sometimes decades, well beyond the typical technology lifecycle and PDF has proven to be a decent as a format for these Long-Term Document Archival cases.
While there have been contenders to replace PDF (XPS, OXPS and EPUB being a few examples), some of which being clearly superior, PDF has continued to hold onto its reign as the king for these two use cases and that doesn't seem likely to change anytime soon.
Ryan