Examples of text customized

black text on white backtround. added space before headings. increased line-spacing
brown text on tan backtground. large main text in serif font. small headings in different fonts, colors, and borders.
black background. main text: yellow and sans serif font. heading text: large, lavender, serif font, and indented

Understanding Users' Needs to Customize Text Display


Some people with low vision, dyslexia, and related conditions cannot read normally-formatted text in books, newspapers, manuals, web pages, PDF documents, etc. (even with reading glasses) because the text is too small, the colors are too bright or too pale, the letters are hard to distinguish, etc. However many can read text that is formatted differently, for example, with larger text, different font, more spacing, etc.

In order to read, some people need to change the way text is formatted; they need to be able to customize the text display aspects.


This page explains users' needs for customizing text:

Who needs to customize text (user group)

Millions of people cannot read normally-formatted text, and millions more will not be able to in the coming years as their vision declines due to aging. An estimated 15–20% of the population has symptoms of dyslexia, and 246 million have low vision (compared to 39 million who are blind). [stats]

Text customization is needed by the largest groups of people with "print disabilities"[print]: those who can see and can read, but have difficulty reading normally-formatted text and need change the way text is displayed in order to read effectively; including:

The needs of people with declining abilities due to ageing are becoming more and more of a priority for software design.

(While some people need text customization, others with 'situational limitations'[note] can benefit from it, for example, people without disabilities reading in a car with low light when they are tired.)

Readability beyond legibility

In order to understand the needs of people to customize text for reading, it is important understand the distinction between legibility and readability. Legibility is related to perceiving text by distinguishing letters. Readability is related to reading and comprehending textual information. [readability] Thus text could be somewhat legible to a user, yet not functionally readable. That is, with effort a user could distinguish one letter from another, but could not effectively read sentences because of the text formatting.

For example, in a User Research Survey, respondents commented to the question, "What happens when you read "normal" text, such as a newspaper, or text on a computer that is not displayed how you like it, such as a pale text on a bright background?":

When text is not customized

Some people cannot read normally-formatted text at all. Some people can read it with varying difficulties. For some (such as Ben), being able to customized text is a convenience; for others (such as Ramón and Angelita), being able to customized text is a requirement.

When asked what happens when people read "normal" text, or text on a computer that is not displayed how they like it, User Research Survey respondents said they experience:

Sometimes people give up. More than half of the survey respondents "quit reading information from the computer (such as an article on the web or instructions in PDF) and not finish it, just because the text is too hard to read comfortably" often every day or a few times a week.

Please see When Text is Not Displayed Well for enlightening comments and survey data.

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Without customization there are conflicts

There is not a single text format that will meet most users' needs. Research results and published guidelines have different recommendations for specific aspects of text format. For example, leading/line spacing recommendations for people with low vision, dyslexia, or who are older, range from 1.25 to 2.0. [guides] A study of user style sheet settings found that some people (7) set a sans-serif font; some (3) set a serif font, and some didn't set the font at all. Font-family settings were: sans-serif, Verdana, Arial, Helvetica, Trebuchet MS, Times/Times New Roman, and APHont.

Without customization, a user's needs can conflict with general best practice. For example, in a study on how people customize text with RTF and PDF files, a participant with dyslexia said, “I write and read a lot better in all upper case”; whereas, all guidelines I've found suggest avoiding all caps, for example, those listed in the references.

Without customization, a user's needs can conflict with visual designers' aesthetic choices. For example, respondents to the User Research Survey commented:

Without customization, one user’s needs can conflict with another user’s needs. For example, many people with declining eyesight due to ageing need high contract between text and background color; whereas many people with dyslexia and other reading impairments need low contrast. [contrast] Most text is displayed as dark text on light background; however, some people cannot read with bright backgrounds and need light text on dark background. User Research Survey comments included:

The study of user style sheet settings found that people set conflicting colors. Of those analyzed, 6 set dark text on light background; 5 set light text on dark background; (some didn't set colors). Most color settings were high contrast (21.00:1) black and white. One global style sheet set low contrast of 4.75:1.

Not only are there differences between users, individual user’s needs are sometimes different depending on their situation. Participants in the RTF-PDF Study and respondents to the User Research Survey reported that their needs varied depending on the amount of text to be read, the time of day, fatigue, and the complexity of the information.

All these potential conflicts clearly point to the requirement for users to be able to customize text according to their specific needs at a given time.

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Adaptive strategies fall short


Some people who need larger text use screen magnification software to increase text size (and images and everything else), change colors, and sometimes read text aloud. However, screen magnification has drawbacks. Angelita says:

"I absolutely hate using the leading adaptive screen enlargement programs like Zoomtext and Magic because they tend to enlarge every image equally and waste a lot of space on the screen."

Screen magnification software often requires people to scroll horizontally to read lines of text; however, some people cannot effectively read text that requires horizontal scrolling. Survey respondents commented that horizontal scrolling with screen magnification software made them nauseous, disoriented, and frustrated.

Screen magnification does not allow users to customize many aspects of text display.

Screen magnification software is not a viable solution for some people because of insufficient functionality, complexity, availability, cost, or other factors.

Copy, paste, customize

When people are using a program that doesn't support text customization (or it's too hard to figure out), a common strategy is to copy text (e.g., from a web page), paste it into a word processing program, and customize the text there. For example,

Copy and paste also has limitations. Often the semantic markup is lost in copy and paste, for example, headings and lists are not preserved so the paste looses formatting to distinguish elements.

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Referring to this material

Please be careful in referencing the information on this tader.info website as from the individual Shawn, not related to her employer.

Some of the information on this page is published in peer-reviewed papers, which might be better for referencing in scientific papers and such. See Research for links to the papers.

Depending on what format you use, a reference for this page might be:

Henry, Shawn Lawton. (2016) Understanding Users' Needs to Customize Text Display. Available: http://www.tader.info/understanding.html. Last accessed 4 January 2016.

See also

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Notes and References

About 'situational limitations':

Accessibility also makes products more usable by people in a wide range of situations. Situational limitations come from circumstances, environments, and conditions, and can affect anybody—that is, people without disabilities as well. For example, situational limitations include using the Web on a mobile phone when your eyes are busy (such as driving), in bright sunlight, in a dark room, when your hands are full, in a quiet environment (where you don't want it to make noise), in a noisy environment (where you can't hear well), and in an emergency (when you may not be thinking clearly). Thus, while access to people with disabilities is the primary focus of accessibility, it also benefits people without disabilities and organizations that develop accessible products because designing for functional limitations overlaps with designing for situational limitations. — from Background | Just Ask: Integrating Accessibility Throughout Design


Print Disabilities


Adaptive Strategies



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Date: Updated 2 January 2016. First posted 2013.