Restores tension to loose canvas without needing to re-stretch or use keys! Tight 'n' Up liquid canvas re-tensioner solves the problem of how to repair a loose stretched canvas. This new liquid technology solves most all of the typical canvas tension problems due to variations in humidity and temperature. Tight 'n' Up helps to remove or improve any previous sagging, wrinkles or ripples leaving the canvas taut and tight. It dries to a clear finish that will not affect the look of the piece. Simply spray onto the back of a stretched canvas. It will cause the canvas to shrink and increase canvas tension. Apply to the entire back surface or only the affected canvas areas. Tight 'n' Up will not harm the canvas, gesso, or typical artists paints. Works best on cotton, linen or other natural fibre canvases. Not recommended for use on polyester-based canvas, oil primed canvas, inkjet printed canvas or Giclee prints. Archival in quality and acid-free.