There are some differences with the type of papers that you will use when you are doing some transfers for light-colored and dark-colored fabrics. For example, when you are trying to do some heat printing for light fabrics, you will notice that a thin polymer layer will be used for sure.
The one that will be used for dark fabrics will be thick and will definitely become more opaque. The one that will be used for dark fabrics is considered to be more versatile. In fact, some people say that they can work for more fabric colors which can be effective if you would like to print out in different colored fabrics.