How to make brush tool alternate between the foreground and background color?

[michaelm52071012]

I'm trying to make a tree graphic with two different color leaves, red and yellow. I downloaded a free brush set from Adobe with a leaf brush. 

I've tried using the Brush Settings Color Dynamics settings but it's not working. It either seems to be mixing the two colors or giving me a whole range of colors I don't want.  This is something I was able to do easily in previous versions of PS (using the 22.5.1 release version now) but can't seem to do in my current version.

Help!

[Jeff Arola]

You could use the X key on your keyboard to switch between the Foreground and Background colors.

[Trevor.Dennis]

Note: brush spacing is set to 50% in this example, meaning each application overlaps the last by exactly half the brush size.

Note also:  Apply per tip, causes the jitter to work as the brush is moved.  Without that it would swap colours every time you start a new stroke.

Same thing with jitter set to Penpressure.  I should have reduced brush spacing for this!

And lastly to Fade.  I have reduced spacing to 5%