Painting Conservation – what is it and why/when is it needed ?
” There is nothing permanent except change” Greek Proverb
The laws of the universe require constant change. A painting ages over time and the changes it experiences can be in the form of deterioration or damage. There have been many advances in chemistry and physics in recent years and one would expect modern paintings to last much longer. However, with all of the advancements have also come a lot of new materials with unknown or very poor aging characteristics and unforeseen consequences to the longevity of the artist’s work. Artwork is now being exposed to many more materials than ever existed before. Some of these are coming into contact with the artwork by accident and others through ignorance.There is such a vast array of chemicals and materials available to anyone dabbling in art restoration that it is a really good idea to either leave your valued piece alone or take it to a professional conservator. The conservator will give it a complete physical exam and propose a treatment that you can discuss before any work actually begin.
Safe and favorable conditions will produce the best aging however this will only be true if the artist has constructed a sound piece of art with quality materials used properly. Environment includes not only air, temperature, humidity, and light qualities, but also adequate support and framing, safe storage and movement when necessary, good hanging systems, etc. Proper environment for art is a subject well discussed in the museum studies field – see the online research published by the Smithsonian Museum Conservation Institute.
Eventually a painting will need to be cleaned. The painting may become heavily grime laden, or the layers of varnish may discolor, oxidize, or deteriorate and a chemical cleaning (removal and reduction of the protective varnish layers) can be undertaken by a conservator. We think that the modern varnishes available today will not yellow as much as the natural resin varnishes used in the past and we are hoping to put off chemical cleanings even farther into the future for the overall protection of the painting. Each cleaning involving solvents can be stressful to the paint layer. Contemporary conservation varnishes remove with solvents that are gentler to the paint surface (easily reversable).
Oil paint undergoes a long chemical change as it dries and the complete drying process takes many years. In the long run there is no predicting what will befall the surface of a painting. Two works by the same artist done at the same time with the same materials can easily look completely different after 100 years due to different environments and, more than likely, different restoration treatments. It is impossible to tell if a painting is cleanable just by looking at it. A conservator can usually tell if a painting needs cleaning or needs conservation just by looking but knowing if it is safely cleanable is a different story. A physical test must be done.
Oxidized yellow varnishes are not always safely removable. Some antique resins are completely insoluble and impossible to remove, others are not true artist’s varnishes. There are many unfortunate cases of linseed oil “feedings” that tend to irrevocably darken paintings & cases of insoluble polyurethane applied to the surface locking in all the dirt and grime under a cloudy yellowed layer.
All paintings clean differently. Usually there is a dirt layer on top of an amber yellow/brown natural resin varnish layer. “Usually” unfortunately doesn’t happen all that often. Most paintings have been tampered with in some way. People have used all kinds of cleaning solutions and coatings on the surfaces of paintings so the conservator never knows what will be encountered. Various soaps are used to remove grime,dirt, grease, and nicotine layers. Various solvent solutions are used to carefully remove and reduce oxidized varnish layers and the conservator tries to go down layer by layer.
There are always some exceptions but usually, after cleaning, the painting is revarnished to protect the surface. The surface reflectance of the final varnish can be adjusted by the conservator to make the painting look either glossy, semi-matte, or completely dead-matte. It is usually a very good idea to apply a protective, non-yellowing varnish as this acts as a stable protective barrier to the paint layer and also saturates the colors.
Some artists do not want the final look of their paintings to be varnished. Conservators do not have to apply a final varnish however it will leave the painting unprotected and most likely shorten the painting’s life. The dirt, dust, stains and fingerprints landing directly on the paint layer will eventually change the look and alter the artist’s original intent.
The best varnishes are stable, slow to yellow, and are safely removable even after long periods of time. There are only a few varnish resins that meet these criteria and much research has been done in trying to find and fine tune the ideal picture varnish.
If your canvas is torn, or your panel is cracked, or the paint is beginning to lift off the surface you need structural repairs.
Many small sized tears can be patched with reversible adhesives and soft synthetic canvas. Cracking or broken panel paintings can sometimes be treated by a cradle being applied to the back. Raised cracking through the paint layer can be consolidated with the proper adhesives that will not stain the original colors or change the characteristics of the painting. Treatments are chosen based on properties of the painting and damage.
Larger tears in canvas paintings will require lining – an addition of a second canvas to the reverse using a proper lining adhesive. Beva 371 was developed by Gustav Berger in the late sixties to replace the traditional lining adhesives (beeswax/resin, starch paste or animal glues) used in the past. Most of these natural glues and resin mixtures will darken over time (and some darken dramatically) changing the entire tone of the picture. Beva 371 is a modern combination including an ethylene vinyl acetate copolymer resin that is strong, reversible, non-yellowing and non-staining.
There is no way to quickly fix or clean & re-varnish a painting. All of the above takes time and it takes time to do well. The costs depend on the number of hours that will go into the work. The conservator charges for time and expertise in the preservation of your artwork.
Size has a lot to do with treatment costs in conservation. The most expensive treatments are the ones that require the removal of a lot of poor restorations and repairs done in the past. Removal of crosslinked varnishes, patches, linings and adhesives are the most time consuming jobs. One of the laws professional conservators follow is to always use reversible materials. It is a nightmare to encounter irreversible materials used in previous restoration campaigns that need to be removed.
Conservators are not out there deciding what gets treated and what doesn’t. Due to the costs involved owners have to decide which of their paintings to conserve. Generally the prices of art conservation are very reasonable considering the longevity of professional conservation treatments and the high value of collectable paintings and period frames.
You can find people who dabble in restoration as a hobby or as a sideline who obviously charge a lot less but if an appraiser gets a sense that a valuable piece has been poorly restored it will drop the appraised value. Poor treatments can usually, but not always, be removed or reduced by professional conservators but this work can be very time consuming and expensive. The artwork should have some value, either historic, sentimental or monetary to justify the investment. Turning the artwork into something more valuable may or may not be the case after treatment. If the painting is valuable to begin with and the conservation is well done the preservation treatment should only add value to the piece. Conservators do not add value by turning poor paintings into something great. A badly painted portrait before conservation will only be a well preserved badly painted portrait after conservation. If you do not know anything about your piece some research may be warrented before you bring it in for conservation. AskART.com is a good place to start if the painting is signed and you are looking for some information on the artist