Aha, of course, I totally forgot about black N white being necessary.  And you're right, I've got it the wrong way around... duh!

Also when I now try it (and it's working, so thanks) I find that my brush is cutting off the stroke rather abruptly and the tuts looks like his brush can do partial fading at the ends of the stroke - the one he's removing the ends of with this faint red mask painting - but I can't seem to duplicate that, how is that possible?

Ha!  it's okay, I've found it, I just changed to a softer brush... I tried to find out how to make the current brush softer by looking at the brush settings but none of those "Brush Dynamics, jitter", etc things seemed to make sense, they certainly didn't look as if they were helping, so now I'm also wondering how you can make a brush softer at the edges... if you wanted to make a brush, with soft edges.

Cos I'm wanting to (later) make a grunge brush and I wanted the edges soft...

So, how do you do that?

Measure your mind's height
by the shade it casts.
Robert Browning (Paracelsus)

Fran's Freestuff

http://franontheedge.blogspot.com/

http://www.FranOnTheEdge.com