Anyone who has read a PDF on their smartphone is familiar with the experience of having to pinch their fingers to zoom in and out and scroll around. Jakob Nielsen, co-founder of the user experience research and consulting firm Nielsen Norman Group, has researched the shortcomings of PDFs for 20 years and the most recent assessment he co-authored is simply titled, “PDF: Still Unfit for Human Consumption, 20 Years Later.”
In the article, co-published this week with user experience specialist Anna Kaley, several reasons are given as to why PDFs are problematic when used for online reading. Some of the usability issues mentioned include a jarring user experience, slow load times, unnecessary content, unnavigable content masses, and the fact that PDFs are sized for paper and not screens.
“The format is intended and optimized for print. It’s inherently inaccessible, unpleasant to read, and cumbersome to navigate online. Neither time nor changes in user behavior have softened our evidence-based stance on this subject,” the article reads. “Even 20 years later, PDFs are still unfit for human consumption in the digital space.”
It’s an opinion Nielsen has held since 1996, when he first wrote about the subject. However, not everyone shares Nielsen’s point of view.
“Nielsen is right about one thing: people often use PDF when they ideally would use HTML,” Duff Johnson, CEO of the PDF Association, told Motherboard in an email. “That’s not really a problem with the PDF format, merely a testament to the ease of creating PDF and its reliability in contrast to available alternatives.”
“For the rest, PDF is not the problem. The format includes a variety of features that address Nielsen's concerns and has done so for almost 20 years. These features require applications to support them. The advent of browsers as mainstream PDF viewers did set back this development for a time, but that’s rapidly changing,” Johnson said.
When it comes to digital and online spaces, Nielsen and Kaley’s article argues that PDFs should be avoided. If it is necessary to present information online through a PDF, an HTML gateway page should be used that summarizes the key points of the PDF and gives users the option of downloading it instead of opening it up in a new browser window.