Whether you scored a great deal at a second hand store or found Great Aunt Dora’s 60-year-old masterpiece in the attic, you probably want to clean that oil painting before hanging it in your living room.
This job can be undertaken at home, but the amateur art conservationist needs to understand that this time consuming process requires patience.
Cleaning a painting and bringing it back to its former glory is not a project for a rainy Sunday afternoon.
The ongoing process can take many hours and may become a temporary hobby, if only to complete the one piece.
What You Can Expect To Find
Old paintings are somewhat degraded by virtue of exposure to sun, airborne chemicals, and natural decomposition of the materials used to create the piece. The canvas fibers weaken over time, the paint can become brittle, crack or craze and varnish yellows or darkens.
A painting that has hung for many years may have been dry dusted to remove loose debris and cobwebs. Unfortunately, most paintings will have accumulated sticky residue from cigarettes smoke, fireplace soot, kitchen grease particles and other gummy airborne substances. In turn, this film attracts dust particulates and adds yet another layer of grime. There may also be brown fly spots. These hard dots adhere resolutely to the surface, giving it a freckled appearance.
All this needs to be removed without compromising the paint and without using enough pressure to damage the underlying canvas support.
Cleaning Your Painting
You should determine if the painting has been varnished and how many layers you are working with, as well as what type of surfaces they are. Removing the painting from the frame will allow you access to the sides and edges, which will help to visualize the original colors and give indication of the layers of paint and varnish.
The painting should first be dusted with a soft bristle brush, like a watercolor mop brush or a woman’s cosmetic powder brush. This will remove any loose dust and particles. A very soft bristle brush may be used carefully if there are crevices holding stubborn particles.
Exerting a lot of pressure from a vacuum or canned air could be dangerous if the canvas is weak. It is possible to tear the canvas with too much air pressure, so care must be taken to keep air pressure low if one of these tools is used.
If those products are not available, use a clean soft cloth and moisten with water mixed with a tiny amount of dishwashing detergent. Make sure the cloth has been wrung out to eliminate excess water. Gently dab the cloth onto the paint. Do not rub and be very gentle with this procedure. Start in an inconspicuous corner to make sure there is no damage. You can use this method to work your way over the painting. Do not get any excess water on the surface and work in 2-inch sections, using only clean areas of the cloth.
If the cleaning solution is not sufficient and the painting has been varnished, solvent can be used to remove the varnish layer. Use solvent specifically made for oil paint varnish, such as Winsor & Newton Distilled Turpentine or Artists White Spirit. Use cotton swabs with the solvent to remove the varnish layer gently. Roll the swab across a small area and discard as it becomes soiled.
This process can also remove the oil paint, so a gentle touch and patience are very important. Start in an inconspicuous corner to ascertain there is no damage before proceeding and work in small sections. If any color comes off onto the swab, you are using too much pressure or concentration of solvent.
After The Painting Has Been Cleaned
Once the varnish has been removed, the painting needs to be re-varnished using a flat bristle brush and straight strokes. Winsor & Newton, Grumbacher, Old Holland and many other art supply manufacturers produce varnishes to recoat your painting. After drying for 24 hours, apply a second coat if the sheen is uneven. You can use either a satin finish or a gloss finish, as either will provide safe and permanent protection.
Please note that if this is an investment piece or is of great value, an expert should be consulted to do the restoration work. This is a job that requires patience and a light touch. Professional conservationists spend years studying and practicing, which accounts for the cost involved with professional restoration.