Control Lines tutorial?

I have checkout the site but I can’t find any tutorials for the use of control lines. It seems like an enhanced version of gradients but that may be because I am simply not using t correctly, so a tutorial would be nice.

Try this.

Hi Woodmeister,
Did you see this post?

It’s a bit techical but if you use a few images to do some tests to see how it reacts you wil get the hang of it.