Hi have been using colour graphics for years and have always had amazing results. Recently the graphics have been drying up really quick and not taking. It's also uneven I'm finding that the graphics on the top take much quicker than the ones underneath which I thought would be the other way around because of the heat from the head? It's been taking around an hour to take and then the end result is still yellow? Was wondering if anyone else has had a problem or if anyone knows if the have changed the promotors or powders?