How to prime a canvas for posca

Something I find very difficult is how to prime my canvas before I draw with posca on it. I have tried to prime with plain white cheap gezzo. I use a wide paintbrush to put it on the canvas.
I have to be careful to get enough on the canvas to cover it completely.

To help me to ensure that I get primer on the whole canvas, I tried to use a light blue acrylic paint. I wanted to draw a fanart Nemo from the movie Finding Nemo.

It was much better to draw on the canvas with posca after I primed it with acrylic paint. There where no areas that was not covered. I could then go on an make the actual painting with posca to see how it behaved.

It is a bit difficult to actually see on my painting, but I am not completely satisfied with the orange posca. You kind of have these dark areas becouse of the blue primer. I went over the orange posca color several times.

Prime paper for posca

Recently I bought a light table so it gets easy to get my sketch onty a canvas. I use a thick 300g water color paper as my canvas. I have tried different kinds of paper, and they all started to bulge when the primer dried.
As primer I tried both the Gezzo and the light blue acrylic paint. Both got the paper to bulge so it was useless to draw on with posca.
I got some okay results painting both sides of the paper with my primer, but that is a lot of work every time, and also messy!

Lastly I got a tip to use spray paint to prime my canvas, which I then tried. That was really easy to use and the result was awesome. I used the cavas to draw some fanart Minions from the movie Dispicable me

The spray paint as primer was really good. It still have some problems that I am not satisfied with, but all in all it was much better to draw on with poscas.