Not having enough colour contrast is a common accessibility issue ... simulators available to check colour combinations when creating documents, particularly charts and graphs, are: ...

Contrast and color use are important, as users must be able to perceive content on a page. You can use accessibility checkers to check for issues such as color contrast ratios. If you choose to use ...

as not everyone with sight sees colour in the same way. Additionally, ageing affects visual acuity, perception of contrast and colour saturation.