Linen is a strong and durable cloth woven from thread made from fibers of the flax plant. Its strength makes it an excellent surface for creating enduring paintings. In fact, because of its strength, linen holds up to heavily textured compositions and does not become slack as easily as cotton canvas. The threads that make up linen, which are known as the warp and weft threads, weigh the same, which means they are less prone to expansion or contraction due to moisture. Linen also retains its natural oils, which helps to preserve the fiber’s flexibility and stops the canvas from becoming brittle.