Twisted Fate cosplay... halp

So uh I have been working on a Twisted Fate cosplay recently and I was working on the cards. I planned to spray paint the designs on and cover up the designs (such as how the red card has the sword shape, cover that then spray paint the rest of it red) but when I spray it, this strange bubbly-veiny like thing happens where the paint kind of rises off the card... It has done that with every card I have tried. Does anyone know a way that I could do this and make it to where the cards do not get the bubbly-veiny like thing to happen? :D