...to see if it is useful for our company to put some extra attention into our designs for those who are colourblind.
It's not just colour-blind users who can't see certain colour combinations - actual blind people can't either, so you need to ensure data isn't represented purely visually.
Webaim have some useful info on this topic that covers off the different types of colourblindness - http://webaim.org/articles/visual/colorblind. The most important thing to take from this article though - don't rely on colour-only when representing any information on screen.
However, the main type of colour blindness is red-green, although there are a variety of other types, as outlined by Webaim:
Red-Green Colour Blindness:
The most common broad category of color-blindness is often called red-green color-blindness, but this does not mean that these people cannot see reds or greens. They simply have a harder time differentiating between them. Not all reds and greens are indistinguishable. It would be easy for someone with a red-green deficiency to tell the difference between a light green and a dark red, for example. A lot depends—at least in part—on how dark the colors are. If the red is approximately as dark as the green, there is a greater likelihood that the colors will be confused.
Challenges and Solutions
- Reds and greens are often indistinguishable. This is not normally a problem except in cases where the colors convey important information. Under these circumstances you will need to either change the graphic or provide an additional means of obtaining the same information. Oftentimes the most appropriate way to do this is to provide an explanation in the text itself.
- Other colors may be indistinguishable. Same as above.
It's more of a contrast issue that specific colour issue in general though. Ensure your colours are of sufficient contrast to pass W3C WCAG guidelines. As I've paraphrased much of webaim here I might as well continue in the same vein:
From WebAims page on colour contrasts:
WCAG 2.0 level AA requires a contrast ratio of 4.5:1 for normal text and 3:1 for large text. Level AAA requires a contrast ratio of 7:1 for normal text and 4.5:1 for large text.
So in general: You can use colour for decoration and styling with almost no issues. But when it comes to representing data or other information then you can use colour provided it passes contrast ratios and it isn't just colour that you're using to get the information across.