Restoration of Works on Canvas
Hopefully, you will never be faced with damage to paintings on canvas–damage that often is severe. Improper storage and accidental mishap are two of the major causes of damage. Lack of surface protection, like that provided by glass or acrylic sheeting on watercolors, drawings, etc., allows unexpected damage. Once the damage occurs, you are faced with some decisions. Is the value (personal or monetary) of the work high enough to warrant professional restoration? Is the damage minor, possibly enabling you to repair it yourself? Where can you go for materials for restoration?
Before any amateur tips or techniques are shared, it should be explained that the only way to restore damage to canvases in a totally archival way is to deliver the damaged artwork to restoration professionals for repair. They are trained to deal with every aspect of the work, from period paint composition to fabric reconstruction to up-to-the-minute, non-evasive methods. If you are lucky enough to have a valuable artwork, always consider using a professional restorer.
That said, we will now examine two types of damage most often associated with works on canvas: tears/holes/rips and flaking or scrubbed surfaces. These two problems can be corrected without extreme amounts of knowledge or training, but only if maintaining the value of the artwork is not a factor.
To repair tears, you will need some basic repair materials before you can begin. These are now readily available from art supply centers and are manufactured by several companies. First and most important is an acid-free, archival adhesive, often vegetable based but sometimes synthetic; small pieces of cotton canvas (larger than the tear or rip); brush for adhesive application; brush to remove excess adhesive; books or wood to elevate the back side of the canvas; smooth weights (or books) to apply even pressure to the repaired area; and fingernail scissors.
Rips and tears in painted canvases occur when trauma has occurred to the front or back of the canvas. Once painted, there is less stretch or give in the fibers of a canvas and the surface becomes somewhat brittle. But, nevertheless, there is only so much “give” in the surface of fabric to start with. If an item has been allowed to fall against the front or back of a painting and has caused a rip or two-way tear, there is a simple and widely accepted method of repair.
Apply an acid-free adhesive to a piece of fresh canvas large enough to cover the tear. Press gently to adhere the canvas to the back of the painting. Carefully turn the painting over. Support from the back side of the painting is essential as you work on the repair. This support can be a book or small scrap of wood covered with plastic. The book (or wood) should be the same thickness as the canvas stretcher bars so that it will elevate the painting to the proper height without stretching. Press against the canvas patch you just glued to the back of the painting. From the front, gently bring the edges together and work any frayed edges of the tear into the soft adhesive. This can be done with a toothpick or similar tool. Use a brush or clean cloth to remove excessive adhesive on the surface of the painting.
Place weight over the repair and allow it to dry completely. Once dry, remove the supports and examine the surface of the canvas. If there are an inordinate number of threads above the tear, carefully trim with nail scissors. If they are not trimmed, they will show later.
When the surface is as smooth as possible, apply paint of the same type (oil, acrylic or alkyd) to the affected area. This should be applied over the tear only, and then gently smoothed into the surrounding area.
Scrubbed areas are much easier to repair. Paint of the same type (again oil, acrylic or alkyd) should be mixed and applied very sparingly to the areas where damage is noticeable. Allow the newly painted areas to dry completely and then apply medium to match the sheen of the original painting.
When old paintings are chipping or there are areas of deep cracks in the surface, consider going to a restoration specialist. If you want to do some minor repair to help correct or stop the damage, here is one idea. Use painting medium that matches the original paint (oil, acrylic) and carefully work medium beneath any loose areas. Press lightly to reattach chips and then allow to dry.
Cracking on the surface can be serious. It usually indicates an improper fit between the paint and the surface onto which it was painted. Perhaps in the case of an old work, the canvas may not have been properly sized prior to painting. Use medium to hold any loose areas and work it into the crazing, if possible. The end result will be a painting that will last for many more years.
Painting as little as possible over the original is always preferred to painting too much. The less you do to alter the original work, the better. Work with very fine brushes and set the paint on the surface in the exact areas where damage has occurred. Restoration is a very involved scientific endeavor that should often be left to the professional. But, sometimes, we can do a little to help delay professional intervention. Care is the key word.
Canvas — A tightly woven fabric often used as a substrate for painting.
Canvas Weight — The weight of a square yard of raw canvas usually stated in ounces, prior to priming.
Count — Number of yarns in warp and weft per square inch.
Loomstate — Raw canvas with no modifiers or additives.
Picked — Hand process of removing irregular and nubby yarns from raw canvas.
Plied Yarn — Twisting together of yarns into a single braid.
Pumiced — Hand process of rubbing raw or sized linen with pumice stones to achieve a smoother texture.
Strike-Through — Ground and/or sizing penetrating through into the back of the canvas.
Substrate/Support — Surface upon which any paint is applied (canvas, paper, wood, etc.)
Texture — The pattern of woven canvas modified by the degree of coarseness and uniformity of yarns.
Tooth — The abrasiveness of the surface (canvas, paper, ground) in terms of coarseness and porosity.
Warp — Yarns running the length of the canvas.
Welt — Yarns running the width of the canvas.
Reprinted with permission of ARTtalk.com