Okay, if you already know this, don't ruin it for me. I was doing some book covers this afternoon when I came back and discovered something. The crackle on top of acrylic paint was much bigger and more prominent than the crackle paint directly put on top of the book covers with no paint underneath. I wanted to do some backgrounds for samples for a swap. I used red dictionary covers. I did not want the original red color to show through. I had little bits and pieces of the Tim Holtz crackle paint left. I banged it on the table upside down to get the last bit out of the container. That is something I don't like about it. The built-in brush does not extend all the way to the bottom of the container. I have to use other means to get the bottom paint out. Anyway, I did one cover with black acrylic paint. I did not wait and put some of the crackle paint on top. I came back later on and the crackle was much larger than on the other covers. I figure it was because the acrylic paint underneath dried and caused the larger crackling.
You try it and let me know if you get the same results. I still think that crackle paste is a better buy for the money. The crackle paint would be better in a workshop environment if you had enough time and did a thin enough layer.
BTW, I got my crackle paints from Frances at heartsintouch.com. I get the Golden Crackle Paste from my local Dick Blick. I was at the bottom of my one jar and it was still pretty fresh. It was usable and not all dried up. Just an extra tidbit.