In general terms, the elements that are favorable towards accesibility are also considered to be good design practices in the wider sense. While there is not a one-size-fits-all solution, if your presentation is well designed, it should already be accessible to most people. That means when you follow this guide, your presentation will be awesome for everyone.
- Do not use imagery that contains sex, violence, or might hurt the sensibility of your large multi-cultural audience.
- Keep slides clear, simple and uncrowded.
- Use minimal text: cover one subject per slide, ideally using no more than six bullet points.
- Ensure every bullet point or item in a list ends with punctuation (e.g. a Full Stop, Semi-Colon or Comma).
- Make the presentation as multi-sensory as possible; use audio-visual elements to reinforce information.
- Make the slides available online beforehand, tagging @acmrecsys and #recsysYYYY.
- Use bold for emphasis, rather than highlighting, underlining or italicising.
- Align text to the left or centrally; do not justify both sides.
- Avoid text which is angled or uses special effects, such as shadows.
- Avoid white writing on a dark background.
- Dark text on a pastel background works best; dark blue text on cream suits.
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Don’t only rely only on color to convey a message: You shouldn’t rely on color alone to convey a message; for example, certain types of color blindness might make it difficult or even impossible to see a common red error message. One approach is to use both colors and symbols where people’s attention is required.
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Keep it minimal: You should limit the color palette you use for your presentation; the fewer colors you use in your design, the fewer instances there will be for confusion.
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Use patterns and textures to show contrast: Try to use different textures, as opposed to multiple colors, for elements that require emphasis. For example, it might be difficult for color blind people to interpret graphs and charts. In this case, it is better to use contrasting patterns and, where possible, place text instead. Always include a legend in your graphs.
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Avoid bad color combinations: These are color combinations to avoid because they’re a potential nightmare to color blind people:
- Green & Red, Green & Brown, Blue & Purple, Green & Blue, Light Green & Yellow, Blue & Grey, Green & Grey, Green & Black
- High contrast color schemes can be very hard to see. For instance, a presentation with a white background can make it difficult to see colored things on the slide, as everything is drowned out by the white background – especially yellow/green text. It is also very tiring to the eye. Try dark-colored fonts on a light-coloured background.
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Avoid the use of complex visual effects:: moving, flashing or dissolving images and graphics are distracting and cause visual distortion. Keep slide transitions consistent and simple.
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Use Punctuation: When using bullet points and lists, ensure every point is ended with punctuation (e.g. a Full Stop, Semi-Colon or Comma). This will enable a visually impaired user using a screen reader to distinguish between different ideas. Without the presence of punctuation, different ideas will be read as a single sentence and become confusing for the user.
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Use the right font: (22 - 226 pt), sans serif fonts, and sufficient white space. Also, be consistent in your use of font, color and background, and avoid too much variation in font style and size.
- For people who have dyslexia or have low vision, reduce the reading load. For example, they may benefit from familiar sans serif fonts, such as Arial or Calibri.
- Avoid using all capital letters and excessive italics or underlines. Include ample white space between sentences and paragraphs.
- People who have dyslexia describe seeing text “swim together” on a page (the compressing of one line of text into the line below). They often see text merge or distort.
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Include alternative text with all visuals and tables. Alt text helps people who can’t see the screen to understand what is important in images and other visuals. Visual content includes pictures, clip art, SmartArt graphics, shapes, groups, charts, embedded objects, ink, and videos. Avoid using text in images as the sole method of conveying important information. If you must use an image with text in it, repeat that text in the document. In the alt text, briefly describe the image and mention the existence of the text and its intent.
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Make sure slide contents can be read in the order that you intend. When someone who can see reads a slide, they usually read things, such as text or a picture, in the order the elements appear on the slide. In contrast, a screen reader reads the elements of a slide in the order they were added to the slide, which might be very different from the order in which things appear. When making slides available, please take this into consideration.
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Add meaningful hyperlink text and ScreenTips. People who use screen readers sometimes scan a list of links. Links should convey clear and accurate information about the destination. For example, instead of linking to the text Click here, include the full title of the destination page.
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Accesibility of videos: If you have videos on your presentation, make sure they are accessible to visually impaired and hearing-impaired people. Closed captions typically contain a transcription (or translation) of the dialogue, as well as describe audio cues such as music or sound effects that occur off-screen.
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Be specific when talking about visual elements in your slides: try not to refer to ‘the red box’. Refer instead to ‘the rounded red box in the top-right of the screen’.
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Please don’t use red laser pointers: The red light is not easily distinguishable on bright screens. Use a green laser pointer instead. Not only are green laser pointers generally more powerful, and therefore brighter, but they are also easier to see.
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Avoid the use of gender-binary terminology on your presentation: For example, when welcoming the audience, do not use "ladies and gentlemen", "boys and girls", or similar terminology which is not inclusive. For more information read our recommendations on Collecting gender-inclusive data in Surveys.
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Avoid the use of terminology or examples that might be impolite towards certain groups, especially minority groups. Also, be mindful of using cliché examples that depict any social groups or communities in a way that can be percieved negatively.
- Live Captioning is a great idea for people with difficulties of hearing, and also useful to non-native English speakers. We propose to collect data about the need for live captioning, and to consider it in future conferences.
- If the talk videos are published, they should include transcriptions. Youtube adds automatica transcriptions for some videos.
- Using a Q&A system that does not require standing, either by bringing microphones to the audience, or by using online Q&A systems such as sli.do is generally a good idea. I propose to pilot it during the workshops this year, and roll it out next year if it gets positive feedback.
The recommendations collected in this document aim to include:
- Color blind people: Approximately 8% of men and 0.5% of women are color blind to various extents. There is a wide range of types, and severities, of color blindness (Wikipedia page on Color Blidness).
- People with hearing difficulties: Approximately 15% of American adults (37.5 million) aged 18 and over report some trouble hearing (source: National Intitute on Deafness and Other Communication Disorders, USA).
- People with sight difficulties: Aproximately 6% of Americans aged 12 and over are visually impaired (source: National Eye Institue, USA.).
- People with dyslexia: Aproximately 10% of the population are dyslexic; 4% severely so. (source British Dislexya Association).
All the ideas collected in this document are a summary of the the sources listed below.