Painting Conservation & Restoration Tips



The Woodlot Shore 1880 by John D. Barrow



Contents

Preface

The following was written as an attempt to shed some light on what is regarded by many as either a mysterious or unknown profession. Although there are art conservators in many American cities, and the profession is continuing to grow, the work is often misunderstood and the objectives of the conservator or restorer need to be more fully explained and discussed. I hope this essay will be of some help to the general public, art collectors, historical societies, and new museums just getting started. There is a great deal more information to be found at The American Institute for Conservation of Historic & Artistic Works (AIC) and at the Smithsonian Institution Research Information Center . Other informative links can be found at the bottom of this page.

Introduction

As we all know but frequently forget we are living in an ever changing world. It is apparent that the laws of the universe absolutely require this constant change whether we like it or not. The question for conservators is how to effect the best possible changes in a work of art over time so that everyone remains reasonably happy - including the original artist, the current owners, and the object itself.

There have been so many advances in the understanding of chemistry and physics in recent years that one would now expect paintings and other works of art to last much longer. However, with all of the modern advancements in scientific research have also come a lot of new materials with unknown or very poor aging characteristics and unforeseen consequences to the longevity of artist's materials. Look at how poorly 1960's color film or early magnetic tapes have lasted as an example. Also, all 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 right now 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 photograph your piece as received, give it a complete physical exam and propose a treatment that you can discuss before any work actually begins. See Locating and Selecting a Conservator for further information.

With artwork we usually decide that the least amount of change is the most desirable, even though this is probably impossible and in fact not always desirable since some of the beauty of an oil painting has to do with the way the medium ages. (Abstract expressionist, color field, acrylic & "modern" paintings are a different story - these most of us would like to see stay as is, as they looked when freshly painted however the materials unfortunately do not always abide our wishes.)

The Environment

Benign neglect in a proper environment will produce the "best" aging however this will only be true if the artist has constructed the painting with quality materials and has actually constructed a sound piece of art. Environment includes not only air and light qualities, but also adequate support and framing, safe storage and movement when necessary, good hanging systems, removal from war zones, etc. Proper environment for art is a subject well discussed in the museum studies field. Click here for a list of books from AIC to help you.

As of June, 2000 the Image Permanence Institute has published the Preservation Calculator an analysis tool for storage environments. They are also working on a database and datalogger combination that will be able in the future to not only monitor environments for temperature, light, and humidity levels but also interpret the information. This should be a major advance in preservation and environmental monitoring.

One note to add is that proper environment starts with knowing where the valued object is located. It seems hard to believe, but loosing track of a work of art is actually quite easy. Please safeguard your collection first and foremost by taking inventory and building a simple database that includes the location. If you are involved with a local historical society or smaller museum the better database you build the more "in charge" you will be of your collection. Chances are you already have an excellent database ready to go right on your desktop - Microsoft Office Pro includes Access – an excellent database that can thoroughly track your entire collection along with digital images of them. Open Office , sponsored by Sun Microsystems, is a completely free office suite that also contains a data base and is available as a download on-line.

Cleaning

Eventually a painting will need to be cleaned. Dust, grime, and the usual natural absorption of the first original varnish layer by the paint layer will soon require a light dusting and re-varnishing. This is usually recommended when the painting is still fairly new - within the first 5 years. After that, a revarnishing (without removing the underlying varnish) every generation or so will protect the painting and keep it looking exceptional provided the correct varnish is applied. Eventually the painting may become heavily grime laden, or the layers of varnish may 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.

Oil paint undergoes a long chemical change as it dries and the complete drying process takes many years. It is extremely difficult, if not impossible, to clean a new oil painting due to the sensitivity of the paint to even mild solvents. 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. Tests must be done and most conservators will charge you for this testing procedure and the exam that goes along with it. The information is valuable and takes time, like a complete physical exam at a doctor's office.

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. If the original varnish is intact and unstained underneath all the added layers that is a bonus and it can be left in place.

For an excellent essay on the basic issues in cleaning & revarnishing paintings see the article on John M. Brealey, Chairman of Department of Paintings Conservation at the Metropolitan Museum, by Calvin Tompkins, in the New Yorker Magazine, March 16, 1987.

Varnishing

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 (satin), or completely dead-matte and unvarnished if necessary. It is usually a very good idea to apply a protective, non-yellowing varnish (called for in proper oil painting technique) as this acts as a stable protective barrier to the paint layer and also saturates the colors.

It is true that some artists do not want the final look of their paintings to be varnished and curators (owners) should be aware of these requests and respect them. Conservators do not have to apply a final varnish however it will leave the painting unprotected and most likely shorten the painting's life. Dirt, dust, stains and fingerprints will in the future be landing directly on the paint layer thereby changing the look and altering 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.

Structural Repairs

If your canvas is torn, or your panel is cracked, or the paint is beginning to lift off the surface you need structural repairs.

Small to medium sized tears can be carefully re-welded and re-woven. (Patches are not applied since they will just about always leave bad distortions in the canvas and a raised mirror image of the patch on the surface of the painting). Cracking or broken panel paintings can be expertly treated by specialists with woodworking skills - this is a real art. 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.

Larger tears in canvas paintings will require lining - an addition of a second canvas to the reverse using a proper lining adhesive. Beva 371 has been developed by Gustav Berger 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 of wax (a paraffin) with an ethylene vinyl acetate copolymer resin that is strong, reversible, non-yellowing and non-staining. Beva 371 was originally invented by Mr. Berger in the late 1960's as a way of lining bright, colorful modern paintings without darkening and changing them.

See Conservation of Painting: Research and Innovations by Gustav Berger and William Russell, recently published and available from Talas.

Costs

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.

Generally cleaning and revarnishing even a small painting will take 2-4 hours since the painting has to be removed from the frame, photographed, tested, reframed correctly after cleaning, & photographed on completion. So at $90.+ per hr (average) the basic cleaning of even a small painting would be $150-$300. If the frame needed some work, there was some cracking or staining that required extra time or the oxidized varnish was on top of a dirt layer, or the varnish was crosslinked, or etc., the hours would start mounting up...

The typical size 19th C. American portrait at 30" x 25" can cost about $1000-$2500 for a complete treatment. If the original frame also needs work the costs will be more, in the range of $1500 - $3000 and treatment costs will be much more for a severely damaged piece. The costs just depend on the number of hours that will go into the work.

Tips and Suggestions

Size has a lot to do with treatment costs in conservation. If you have a mural or an oversized painting that needs work you should have some kind of plan in place for fundraising!

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 "vows" of professional conservators is to always try to 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 faster than anything else. Poor treatments can usually but not always be removed or reduced by professional conservators but this work can be very time consuming and expensive.

Needless to say the value of the piece has everything to do with investing in it. The artwork has to have some real value - either historic, sentimental or monetary. It is not a good idea to bring an object in for conservation that has little or no value to you.

The conservator charges for time and expertise in the preservation of your artwork. 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 have it appraised 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. Also, it is a good idea to take some photographs and show these to people and get some initial opinions. This will save you from having to carry the piece around and possibly damage it during transportation.

If you are planning on selling your artwork the new owner will usually appreciate it more if you sell it as is - they will then want to take it to their own conservator after the sale. It is the new owner who will want to make the investment in the conservation treatment so let them do it. A light cleaning and emergency treatment of any insecurities to prevent losses is a common practice before sale.

For further reading, here is a link to a site devoted to the conservation of one painting. You can read the study and look at detailed photographs of the conservator's work. In-Depth Study and Conservation of Johannes Vermeer's Girl With A Pearl Earing by Jonathan Janson.

I hope this has been informative and of some help to you. Any mistakes or inaccuracies are entirely my own. Feel free to contact me with any comments or suggestions, thanks, JS.

Links:



Contact Information

John Sutton
Painting and Frame Conservator
West Lake Conservators
PO Box 45
Skaneateles NY 13152
e-mail: West Lake Conservators

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Updated last: 12/12/2004

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