An update, I'm still not very successful in printing the big canvas.
I tried several different things and there is progress:
By adding 5ml hardener to the photographic emulsion, the emulsion stays on the canvas. However according to the instructions of mahn, manufacturer of Rollei Black Magic, once you use hardener, you need to use the emulsion within 2 hours. However I'm getting strange results, below are some photos of my results.
First photo, used the emulsion after 1h45 of drying: results Streaks
second photo, used the emulsion after 3h30 of drying: result strange "bubbles"
third photo, used the emulsion after 1h of drying: everything fogged and heavy streaks
Does anybody have any idea what the problem is and how I can solve it?
I tried contacting mahn.net, but after a week I still haven't gotten any answer of them.