[hotpockets]

I've used something similar in matlab, which I though worked a little better. It started out with red green blue, colors frequently considered maximally distinct, at least on color monitors for the non-colorblind. Then it just found maximally distant points in the color cube. I found it worked nicely and you could also seed it with your own starting color(s).

Edit: found out it is based on Lab color space.

[svachalek]

I'm no color expert but I'm pretty sure color distance in RGB space is a pretty poor metric compared to other color models (at least some of them). Looking at an RGB color cube I see big splashes of near-identical colors while the entire spectrum of oranges is hard to even find.

[hotpockets]

Looking closer, it uses the Lab colorspace. Here is what I was using: http://www.mathworks.us/matlabcentral/fileexchange/29702

[mturmon]

But, doing it this way can result in oversaturated colors that compete for attention.

[hotpockets]

Interesting point. Though, some of the colors in OPs preset examples seemed very similar, even with only 7 colors. For generating graphs, maximally distinct colors seems the primary goal, even if they compete for attention, perhaps because of it.