According to Colour Blind Awareness 4.5% of the population are color-blind. If your audience is mostly male this increases to 8%.
Designing for color-blind people can be easily forgotten because most designers aren’t color-blind. In this article I provide some tips to improve the experience for color-blind people – something which can often benefit people with normal vision too.
What Is Color Blindness?
There are many types of color blindness but it comes down to not seeing color clearly, getting colors mixed up, or not being able to differentiate between certain colors.
These problems can also be exacerbated by the environments in which people use websites. This could include low-quality monitors, bad lighting, screen glare, tiny mobile screens and sitting far away from a huge television screen.
Relying solely on color for readability and affordance makes a website difficult to use, which ultimately affects readership and sales.
While the following tips aren’t exhaustive, they do cover the majority of problems color-blind people experience when using websites.
1. Text Readability
To ensure text is readable it should pass accessibility guidelines based on the combination of text color, background color and text size.
2. Text Overlaid On Background Images
Text overlaid on imagery is tricky because some or all of the image may not have sufficient contrast in relation to the text.
Reducing the background opacity increases the contrast, making the text easier to read.
Alternatively, you can style the text itself to have a solid color or a drop shadow, or anything else that matches your brand guidelines.
3. Color Filters, Pickers And Swatches
The screenshot below shows the color filter on Amazon as seen by someone with and without protanopia (red–green color blindness). Without descriptive text it is impossible to differentiate between many of the options available.
Amazon shows descriptive text when the user hovers, but hover isn’t available on mobile. Gap solves this problem by adding a text label beside each color. This happens to be beneficial for people with normal vision too. For example, black and navy are difficult colors to differentiate on screen. A text label takes the guesswork out of it.
4. Link Recognition
Links should be easy to spot without relying on color. The screenshot below simulates the vision of somebody with achromatopsia (can’t see color) viewing the UK Government Digital Service (GDS) website.
To find a link, users are left having to hover with their mouse waiting for the cursor to change to a pointer. On mobile, they are left to tap on text hoping it will make a page request.
The links above with icons are easier to see. For those without, it would be a good idea to add an underline.
5. Color Combinations
In the physical world you can’t always control which colors appear next to one another: a red apple may have dropped and nestled itself into some green grass. However, we can control the colors we use to design our website.
6. Form Placeholders
Using a placeholder without a label is problematic because placeholder text usually lacks sufficient contrast. Apple has this problem with their registration form.
Increasing the contrast is not advisable because it will then be hard to tell the difference between placeholder text and user input.
It’s better to use labels – a good practice anyway – with sufficient contrast.
7. Alert Messaging
Success and error messages are often colored green and red respectively. Most color-blind people don’t suffer from achromatism, and so will naturally associate different colors with different messages. However, using prefix text such as “Success” or, my preference, an icon makes it quick and easy to read.
8. Required Form Fields
Denoting required fields with color is a problem because some people may not be able to see the differences.
Instead, you could consider:
- Marking required fields with an asterisk.
- Even better, marking required fields with “required.”
- Where possible, remove optional fields altogether.
The tips in this article are not exhaustive, and they are not necessarily applicable to every situation. However, they do cover the majority of problems color-blind people experience when using websites.
It’s more important to take away the principles, so that you can integrate them into your own design process. Ultimately, websites aren’t just meant to look good – they are meant to be easy to use for everyone, including people who are color-blind.