Satin has a soft, subtle sheen that's neither shiny nor flat, making it perfect for indoor projects on surfaces such as paper, wood, and canvas, as well as for seasonal décor. Gloss, on the other hand, has a shiny, reflective finish that adds vibrancy and durability, and it works both indoors and outdoors on a wider range of surfaces, including wood, canvas, metal, rocks, furniture, and terracotta. In short, choose Satin for a soft indoor look, or Gloss for shine, durability, and an outdoor-friendly option.