The function of heat transfer paper is to firstly print the specific images in the heat transfer paper by heat transfer ink, and secondly transfer the printed images onto the surface of heat transfer materials. The process of the heat transfer printing is to transfer the dyes to textile.
Heat transfer paper can be divided into general heat transfer paper and t shirt heat transfer paper. However, many people don’t know how to identify the surface and obverse of heat transfer paper. To identify the correct side to transfer, primarily we need to know that there are a coating on the surface of heat transfer paper, which differ from other printing paper. Therefore, the surface of heat transfer paper with coating is the correct side.
Here are some tips to identify the correct side:
1. Touch
    Because the heat transfer coating is sticky, it is easy to find the correct side with coating for sophisticated workers. But for the beginners, it is hard for them to judge.
2. Paper thickness
    Paper thickness is the most used method to identify heat transfer paper. Being images carrier, the printing side of Heat transfer printing paper is cruder than obverse which is more exquisite.
3. Folding
This method features in the highest accuracy but extreme. It is recommended until  we still can’t identify the printing side after the first two method. Because of the coating, if the heat transfer papers are put in the air nakedly, the paper will become folded after certain period. Therefore, printing side of the folded paper is up, while the other is obverse. However, folded paper is bad for printing images.