Accessibility of documentation


The intention of a technical writer is usually to inform, guide, instruct or perhaps persuade your audience.

This requires that the documents you produce are easy to read and interpret by all those who need access to them. They must have a good level of accessibility.

So, are your documents accessible? Are you sure that you always consider your entire audience?

For example, there are a large number of people who are visually impaired. This number includes those who have no sight at all, and those whose useful sight is limited to some degree by disease or by damage to one or both eyes.

The visually impaired have to deal with all types of media, in the workplace (or at school) or at home, just like anyone else. Importantly, they want to do this as independently and as transparently as possible.

The focus of this submission is those who are partially sighted and have some useful vision, albeit assisted in some way. Total inclusion of those with no sight at all requires a lot more thought, making full use of their fully functioning senses such as sound and touch. If I may, I should like to come back to that subject at a later date.

When dealing with written or printed media, the partially sighted typically make use of hand held, or desktop magnifiers, and sometimes line scanners linked to CCTV.

Screen output can be adapted to improve accessibility for the visually impaired user. The operating systems of the major manufacturers of desktops, laptops, tablets and phones include at least some basic facilities for magnifying the screen output, and for changing screen colours and contrast.

As a producer of documentation such as user guides, manuals, web pages, forms and so on, how can you improve accessibility?

Your aim should be that all your readers are able to read and correctly interpret what you have written, at a reasonable speed and without undue strain or frustration.

Realistically, this can be achieved by extending existing good practice to include a few valued guidelines. You can do this without adapting the content of what you write.

Page layout

The key elements when considering design and accessibility are simplicity and consistency.

When creating multiple pages, keep left and right page margins the same to avoid confusion.

When producing printed media with a stitched centre fold, use a gutter setting that keeps the text well clear of the fold. This makes it easier when using a page scanner or a magnifier that makes contact with the page.

Text is best set aligned to the left, as a ragged right edge is easier to follow on to the next line. Avoid centred text as the ragged left and right edges can be confusing. Also, avoid using justified text as the space between words will be uneven, possibly suggesting emphasis where none was intended.

Using short paragraphs, spaced well apart improves accessibility.

Include plenty of white space to delimit sentences and paragraphs. The space between paragraphs should be greater than that between lines. Indenting of new paragraphs may hinder the reading capability of visually impaired readers.

Always use even spacing between words in a sentence and don’t remove space in an attempt to squeeze text into an allocated space. Keep the use of hyphenated words to a minimum, especially where this forces a line break.

If you want to use columns within your text body, keep the length of the columns short to help those who are using a magnifier, or CCTV. Do not set the columns too close together, and avoid the use of vertical lines as separators.

Overall, use clear signposting to navigate the document will improve accessibility. Avoid too many heading levels, especially when the signposting of the different levels is a subtle change in font size. Make it clear that a page number is meant to be a page number by isolating it and being consistent in where it appears.


Though opinion does seem to vary studies show that, for most visually impaired people, sans serif typefaces are easier to read than those with serifs. Good examples to use are Helvetica, Arial and Futura.

Serif fonts such as Times New Roman, Baskerville and Garamond can work well as headings. Do not use fonts that simulate written script.


Reserve the use of bold text for headings and titles. Avoid overuse of bold text for emphasis within paragraphs, and don’t underline text if it can be avoided.

Also, where you are using a serif typeface, the italic font can be harder to read than the upright font. There is less of a problem using italics with a sans serif typeface.

Another habit to avoid is using all capitals for continuous text. Research shows that this results in less variation between letters in a word, making it harder to read. Capitals work well in headings because, being larger, they stand out therefore improving accessibility.

Font size

The ideal font size to use depends very much on the degree of impairment and how it is overcome. Remember that in many cases, the visually impaired will be using some method of magnifying the original text.

Those registered as visually impaired often get the opportunity to request correspondence in a preferred format so it useful to have agreed standards.

The RNIB uses the term ‘clear print’ and suggests that 14pt text is suitable clear print for most readers. The organisation also identifies ‘large print’ as being in the range 16-22pt.

It is worth remembering that different typefaces vary in apparent size even though you choose the same font size. It is the relative size of the letter x (the ‘x height’) that determines how large or small typefaces of the same font size actually appear.


There are differing opinions regarding the ideal amount of leading to use. The RNIB suggests that the amount of space between lines should be 1.5 to 2 times the amount of space between words.

Other sources suggest that the target leading amount is 2pt greater than the font size you are using. As this is easier to work out and apply then it may be the preferred method.

Colour and contrast

Colours that contrast each other strongly are preferred by the visually impaired. Conveniently, black on white works very well, and so does black on yellow.

If you plan to use reversed colours, don’t mix dark on light and light on dark. Also, it is worth noting that light on dark results in less glare than dark on light.

When you do use reversed out text, increase the point size of the font.


With many sans serif typefaces, some single digit numbers are hard to decipher, for example: 3, 5, 8 and 0. Also the numeral 1 is easily confused, as in these Arial examples: l (lower case L), I (upper case i), and ! (exclamation mark). The recommendation is to write numbers below 10 in full, i.e. one, two, three, and so on.


For double-sided printed media, use a minimum of 100 gsm paper. Thinner paper can show the print from the other side.

Use paper with a matt finish to avoid reflective glare and improve accessibility.

Conclusions on document accessibility

Obviously, the suggestions put forward here are only suggestions. They are not prescriptive, nor are they exhaustive. You may be constrained by physical space or by specific requirements imposed through corporate identity. Nevertheless, inclusion is a part of good professional practice so please give it some thought when considering the accessibility of your documentation.

The information included here has been gathered from the results of research done by various organisations. These include those with in an interest in specific eye problems such as macular disease, and from the extensive work continually done by the Royal National Institute for the Blind.

It is estimated that there are around two million people in the UK living with sight loss. This figure includes 360,000 people registered as blind or partially sighted; of these, 25,000 are children under 16.

Accessibility of documentation

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