Abstract: An expandable artists' frame with preloading springs therefor, wherein the frame sides are slidably connected together at their ends by an optional groove-and-tongue joint or a hollow angular support and the preloading springs have a strip-like body with toothed ends. For mounting a spring, the latter is placed diagonally with its teeth against a frame corner or the internal surface thereof and then the spring is pushed manually toward the frame corner. During the spring application the spring teeth slide on the side internal surfaces. When stopping the thrust onto the spring, the teeth penetrate into the wooden side and exert a continuous preloading action on both adjacent frame sides. At the spring ends are preferably provided positioning and protection wings.