I am currently writing my masters thesis and I created the following graphic:

[![enter image description here](https://i.stack.imgur.com/b6zY9.png)](https://i.stack.imgur.com/b6zY9.png)

While it looks ok in color, the areas are not so easy to distinguish if this was printed on a non-color printer:

[![enter image description here](https://i.stack.imgur.com/k6TXf.png)](https://i.stack.imgur.com/k6TXf.png)

Do you know any 6 colors which are suitable for this type of image and which can be distinguished if printed with a non-color printer?

(Other ideas how to make sure the reader knows where the numbers come from are also welcome, but I guess colors are the easiest way to do this.)