I have both, I just don't know when to use one or the other. I had been under the impression that the dark transfers painted the "background" white -- everything not printed in another color would come out white. Now, looking at the picture on the front of the Avery paper, I can see that is not the case. There is text with no background while the white in the photo is definitely white. So, it must be that anything with a transparent background stays that way while white still comes out white. That's good news, I'm just still confused on when to use Dark vs. Light transfer paper. Unfortunately, we purchased many dark-colored t-shirts when we probably should have stuck more with lighter colors. Thanks for your help! ...I should clarify... We have many shirts, including yellow, orange, light green and light grey. It's these middle-ground colors I'm not sure about.