Multiple curves overlay problem

[ROCKSTAR]

Hi,
Is there any possible way to show all the curves (each of 4 has different color) in the area where they have the same data points?
Possible solutions which was tested by me:
1. different width of curves. But it leads to creation of fat curves (and actually its not easy to see the other curves, cause of thin lines over the main fat curve), and lower precision.
2. different style of curves(dash lines). But they all should be the same style(line) and width in the area where they DON'T have the same data points.

[ROCKSTAR]

The third solution that I think will work is to mix the colors of the curves in the mutual area. Is it possible to mix curve colors instead of show the first one who is on top?

[Uwe]

You can use semi transparent colors - simply set an alpha value < 255 for the colors of the curve pens.

Uwe

[ROCKSTAR]

Thank you, but its not changes a lot(
Can ask you another question. How can I set min number of steps for axis autoscaling?