Update I am performing rigorous testing on Canvass. We have been discharging them for six months on a daily basis with much success. PC DC has and apparently still does work very well across the board. However with white we would always use a DCUB with a thinned white plastisol on top.
What tipped me off finally was a light gray DC print that had no UB. Intermittently the print would yellow. This a 53 pc run and the yellowing would come and go across sizes. Country of origin is India on all. Mystfying. How can this happen on such a small order? If it were one size that would make a little sense. To make sure we printed another DC base on the reverse side of both the good and bad shirts and the phenomenom repeated. Next I will try full color with no base. Canvass shirts are fine for DCUB in my opinion as the plastisol will hide the yellowing.
Heres a pic
