Many background sets from the original Star Wars trilogy were just oil paintings
Before the advent of photorealistic computer graphics in the late 20th century, movie studios relied on hand-painted backgrounds called matte paintings. These were created by artists who would paint landscapes onto glass using oil paints, acrylics, or pastels.
The original Star Wars trilogy, among other popular films, contains dozens of matte paintings that display unforgettable backgrounds. The fans of this movie series would be surprised to know how many scenes were possible only because of this unique kind of art.