Colour is a cue that allows your audience to see what you want them to see, feel what you want them to feel, and to do what you want them to do. How you use colour also affects the usability – whether people can read your content or not.
Colour has an impact on how we think and behave. It directs our eye where to look, what to do, and how to interpret something, placing content into context. It helps us decide what is important and what is not. That’s precisely why it is important to keep colour in mind when designing your course banner and thumbnail.