Hello Maybe I can get some help, I am using sublimation ink and paper and, I have been heat pressing designs onto metal insert iphone case, but when I heat press a picture onto the metal insert the design comes out fine but it seems like their are slight watermarks in the background, the setting that I am using for the heat transfer is 190 degrees Celsius, for 65 seconds. I use heat tape to tape the image down then I have the image facing up with the metal insert on top, I put white paper on the top and bottom. I am trying to figure out if I am heating them to long or the temp is incorrect?