Category: Design tools

Colour blindness is an eye condition that changes the way people see colours. It doesn’t seem like a big thing to people who have normal colour vision. But when it comes to reading things like maps, it matters a lot. Graphs, maps, diagrams and other graphic information types often rely on colour to differentiate between elements and features.

Apart from genetic reasons, some health conditions increase the risk of developing colour blindness later in life. Macular degeneration, glaucoma, diabetes, dementia, and Parkinson’s disease can all affect colour vision. Because it happens later in life it often gets unnoticed and undiagnosed. Some medications might affect colour vision too. For more, see My Vision guides.

The Axess Lab website has some great tips for making graphics more inclusive. For example, putting text into pie charts, and labelling goods with colours not just showing them. Colour contrast matters too as you can see in the picture below.

Colours that are accessible

Colour is an important part of designers’ creative work. When it comes to colour accessibility the creative path takes a few twists and turns. That’s because people who say they are ‘colour blind’ are not all the same. Most can see some colours, but not all of them. So how can designers choose colours that are accessible, especially in digital communications?

Adobe has a blog page that explains the importance of choosing colours. Four images show the three different versions of colour vision deficiency, which are:

1. Protanopia: Referred to as “red weakness,” this variation of red/green color blindness results in individuals being unable to perceive red light.
2. Deuteranopia: Also known as “green weakness,” this type of red/green color blindness renders people unable to perceive any green light.
3. Tritanopia: People who suffer from blue/yellow color blindness have difficulty distinguishing between blue and yellow colors. This form of color blindness is far less common than its red and green counterparts.

Graphic designers will appreciate the colour wheels and ways to avoid a conflict of colours. Examples of good colour choices show that designs can still be attractive as well as functional. You can try out the online Material Design accessible colour tool that provides information on colour contrasts for visual material. 

Readability and colour choice

Colour choice is also a factor in readability. The video below shows how easily we can be deceived by our eyes. It shows how two different shades of grey are actually the same. That’s why you can’t rely on judging contrast by eye.

Colour contrasts can be deceiving because we are subject to optical illusions. The video below shows how two different shades of grey are actually the same. That’s why you can’t rely on judging contrast by eye. Fortunately there are colour checkers to help with colour choices especially for websites. And why do you need colour contrast checkers? Because more than 8% of the population has colour vision deficiency (colour blindness). 

Colour choice is one factor in readability. Others include using sentence case. Using upper case or capitals does not convey important messages more urgently. The image shows that using upper case to indicate a low bridge did not stop a truck driver from driving under it. Upper case is harder to read because the shape of the words are unfamiliar. 

The most accessible websites are those that have an Easy Read option.  A good example is the My Allied Health Space. At the top of the home page is the symbol for Easy Read and this is where you click to turn it on. 

Thanks to Dr Em Bould, Senior Research Fellow at Monash University for the inspiration for this post. Dr Bould has great advice on this topic based on research. 

More people have difficulty reading than most people think. Low vision, dyslexia, low literacy, and learning disabilities are some of the reasons. Previous posts have covered the topic of plain language and Easy Read. But choosing the right typeface is also important for communicating successfully. Without understanding typefaces, things like colour contrast will make little difference. 

Gareth Ford Williams explains key elements in his article. He says claims of some typefaces being more accessible than others are not backed up by evidence. 

Different typefaces provide different styles in how letters are formed. For example, Gill Sans upper case ‘i’ and lower case ”l’ and ‘1’ look the same. However, in Verdana they are distinct from each other. 

Mirroring is something than young children do. For example, muddling ‘b’ and ‘d’ and ‘p’ and ‘q’. However, the letter flipping effect can be lifelong. 

Spacing or ‘visual crowding’ is another consideration. Some typefaces have the same space between letters regardless of letter width. Helvetica is one example. Calibri has different spacing between letters. A wide letter like m has more space around it than an i or a t. In some cases the letters can look joined up such as ‘ol’ or ‘vv’. Tight letter spacing is not great for people with good vision either. 

The article has several good examples to illustrate points made. The title is, A Guide to Understanding What Makes a Typeface Accessible. Williams makes the point that there is no one right typeface. As always, it depends on your audience. However, this article provides great insights into yet another aspect of communicating accessibly. The article is technical in some places.

Thanks to Dawn Campbell on Linked In for alerting me to this article.