This month,Dr Scott Hollier goes through tips and tricks to help streamline the PDF accessibility process, some good resources being created by the W3C and the extremely useful PDF/UA in providing support to software developers.
Oh, Portable Document Format – or PDF as we generally refer to you — how we wish your accessibility issues weren't so complicated. As a person with a vision impairment, the letters P, D and F immediately create an atmosphere of impending doom: opening said file format will likely result in a frustrating battle to the death between my high contrast colour scheme, screen magnifier, the PDF reader's zoom feature and the screen reader.
Who will win this time? Will it turn out to be a good PDF in which I can find the information easily, or will it be a low-contrast, multi-column, scanned nightmare that renders my assistive technology useless? The mystery awaits with every email attachment, often followed by cursing and violence unfairly directed towards the computer or mobile device being used at the time.
So why does this happen, and does it really have to be like this? These are common questions asked by people with disabilities the world over. To address the second question first — at the risk of having a mob of angry people with disabilities form around me — there are circumstances where PDF is deemed the best file format to use, and in some of those circumstances, making it accessible is tough.
For example, PDFs for magazine publications that are specifically for print will always be an uphill battle to make accessible. Likewise, there are occasions for legal reasons — happily, very rare occasions these days — where a PDF has to be scanned to preserve a signature, or for archiving purposes. While many people with disabilities advocate for the abolition of PDF files, I disagree and acknowledge that there are important reasons why PDF files exist and some of those reasons will lead to inaccessible documents.
However, it's important to recognise that these scenarios are rare, and insignificant when compared with the sheer volume of PDF files created every day, which could be easily made accessible, but are not — such as those created from Word documents.
This month, I'll go through a few tips and tricks that have been shared with me over the years to help streamline the PDF accessibility process, some good resources being created by the W3C and the extremely useful PDF/UA in providing support to software developers.
Why are PDFs so difficult?
At its core, the idea of a PDF is very useful: take a really big unwieldy document, shrink it into a more manageable size for online publishing, ensure uniformity in presentation across different platforms and add security features to make sure that the file can't be easily be changed. To appreciate the effectiveness of a PDF file, you only have to look at the Microsoft Office suites on Windows and Mac, and see what happens when you create a document in one and open it in the other. PDFs aren't perfect but they do have their uses and they're here to stay.
The problem is that the things that make PDFs great are also the things that make them so hard for people with disabilities. With PDFs starting out as a proprietary, locked-down file format that continues information difficult or in some cases impossible to change, accessibility becomes very hard: if you need to make the fonts a bit bigger or change the colours, you can't so it easily or directly like in Word, you have to get the PDF reader to try and put its colour scheme on the document. In many cases, they don't work very well.
Trying to juggle the PDF reader's zoom with a third-party magnifier to avoid a pixelated mess has improved over the years but it is still a challenge, and screen reader compatibility varies wildly depending on how the document is formatted and how PDF support is implemented on the particular device.
People with mobility impairment are also often frustrated by the rigid document format in getting to particular sections of the document. In short, PDFs can be tough going in many cases. While PDF became a publicly available standard in 2008 and compatibility with assistive technology is always improving, many of the issues still remain.
Do I really have to try and make my PDF accessible?
While PDF accessibility is hard for people with disabilities, it's not always easy for content producers either. Given that navigating the waters of PDF accessibility is initially viewed as a bit daunting, it's not unusual to be asked whether or not it actually has to be done. Fortunately, these days the answer is generally yes, and many countries provide some guidance around PDF accessibility requirements.
Here in Australia, the government has stated that:
"PDF does not yet have approved Sufficient Techniques to claim WCAG 2.0 conformance, so it cannot be 'relied upon' in the provision of government information. At least one other format must be provided with all PDF documents."
Recommendations by the Federal government include:
- Always tag PDF files;
- Work with properly structured source files; and
- Avoid scanned PDFs, or at least optimise them for accessibility (e.g. using Optical Character Recognition).
While polices will differ from country to country, there is a general consensus that PDFs are challenging and that accessibility needs to be considered in their production.
The good news is that while PDF accessibility can seem a bit tricky, there are a number of helpful tips that can make the process much easier and make PDFs as accessible as possible.
Does my document have to be a PDF?
While chances are you've already considered this question, it can be helpful to stop and think about the audience of the document you're creating. Does it really have to be in a PDF format? Would HTML or an editable document still achieve your purpose? Sometimes PDFs are created out of habit rather than necessity and it is worth considering this question when creating PDFs.
Make the source document accessible
There's a good chance that the PDF you are creating is being exported from another file type, such as a Word document. If this is the case, look at how best to make that source document accessible before turning it into a PDF.
Microsoft has published a guide for creating accessible Word documents that includes accessibility tips such as adding text labels to images, marking up the document with correct styles and headings and avoiding using blank cells. Word 2010 and later versions also have an accessibility checker that can further help prepare the source document before it is converted into a PDF.
If accessibility is considered at the source, there's a much better chance that the PDF document will be accessible.
W3C PDF Techniques for WCAG 2.0
The W3C Web Accessibility Initiative Education and Outreach Working Group (WAI EOWG) continue to build up a comprehensive resource around PDF accessibility techniques as they relate to WCAG 2.0.
The techniques include items such as:
- Adding alternative text to images in PDF files
- Ensuring a correct tab order
- Effective link text
There are currently 23 techniques, which I highly recommend incorporating into your work practices. Adobe also has some good PDF accessibility resources.
Auditing a PDF file
The techniques document referenced above also provides a comprehensive list of PDF accessibility checkers that can be used to verify whether your PDF is accessible, before it gets distributed or published.
PDF/UA for software developers
PDF Universal Accessibility (PDF/UA) is an ISO Standard PDF/UA (ISO 14289-1:2012. Essentially, the standard is a set of guidelines for software developers providing guidance including an individual developer, PDF generator, or PDF viewing agent. PDF/UA also specifies the rules governing the behaviour for a conforming reader. While content producers rely more on the techniques described above, PDF software creators should be aware and implement the standard. Access iQ™ also interviewed Duff Johnson when PDF/UA became an ISO standard.
Providing an accessible alternative
One of the best tips for ensuring accessibility is to include an accessible alternative format. There is some debate as to which format is best, with examples including Microsoft Word (.doc), Rich Text Format (.rtf), or even a HTML webpage. Ultimately, as long as the alternative contains the same information as the PDF and is accessible, it'll be of great benefit to people with disabilities.
So while the reality of PDF is that it's here to stay, and the frustration and gnashing of teeth is likely to continue for people with disabilities, in most cases you have the power to make a difference on the accessibility of PDF files. Please take these considerations on board, as well as the many other suggestions on PDF accessibility out there; not only will you help people with disabilities get access to information, you will also help to protect the many computers and tablets that meet an unexpected demise as a result of PDF frustration.