This liquid canvas re-tensioner improves or removes sagging, wrinkles and ripples in stretched canvas, leaving a tight and flat surface. When applied to the back of a painting, it causes the canvas fibers to shrink slightly, then penetrates them with a binding agent to retain the tension after it dries. This product is acid-free, archival and dries clear so it will not affect the look of the finished piece. It may be applied only to the problem area or evenly across the entire back surface. This product is for use with acrylic-primed canvases only. Do not use with oil-primed canvas. Use at your own risk for Giclee or ink-jet printed canvases. Available in 4 oz., 8 oz. and 16 oz. pump spray bottles and a 32oz. refill.