Color blindness is a vision disorder in which individuals lack one or more color receptors. It affects approximately 8% of males of European descent and 0.5% women. It means that in an audience of 16 people, half men half women, chances of having at least one color-blind person are of 50%. Of course when you consider the audience of a written piece of work this number may grow quite substantially. Therefore it is important to have a color palette that is suitable for color-blind people.
The image below was made based on the recommendations that appeared in Nature Methods and are the RGB codes in 8 bits, i.e. from 0 to 255.
Of course when making plots you can also change the style of the points, from circles to squares or crosses to make it even clearer.