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Peter Kostoulakos

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Preserving Paintings: Before and After

A Question of Responsibility

by   Peter Kostoulakos

Who is responsible for the preservation of a painting - the artist or the collector? Before an answer can be given to such a question we should explore the term "preservation" as it relates to a work of art.

The preservation process does not start at the time of completion, nor when the painting reaches a matured state. It starts at the very beginning of its creation with the use of properly prepared materials, sound technique, a protective varnish layer and framing. This, of course, is the responsibility of the artist.

When the ownership of a painting is transferred to a buyer or collector it is then his or her responsibility to oversee placement, hanging, care, cleaning and conditions of climate. These are all factors of preservation.

It is my belief that most artists are truly concerned with the longevity of their work and take pride in all aspects of its production. After all - if the artist displays little concern or respect for his artistic creation then how can a collector be expected to!

Painting is a craft - a developed skill involving intellect as well as emotion - but it is also a profession and artists should be professional in their choice of materials and techniques. This starts with quality canvas stretched over a well constructed "stretcher" frame capable of being "keyed" out at 45 degree angles. Some contemporary painters try to economize at this point by stretching low grade canvas over homemade "strainers". A strainer is a frame that is joined fast at the corners and cannot be keyed out to create a taut painting surface. This induces "sagging" and "draws" from the corners which in turn hastens the cracking and flaking of a painting.

Some artists of the not too distant past used high grade fabric and stretchers and then, to save a few pennies, primed their canvas with ordinary house paint. "Sizing" and "priming" a top grade linen when preparing a canvas are major steps in preserving paintings. The paint layers, or image we see and appreciate are resting on this foundation and, if the foundation is weak the structure crumbles. If an oil based primer is going to be used the fabric should first be sized with rabbit skin glue. This separates and protects the fabric from the oil. Linseed oil, when allowed to come in contact with raw (linen) canvas, will dry out and eventually rot the fabric.

One of the most important considerations for creating well preserved paintings is technical procedure. There are many philosophies on the subject but one of the most basic, yet essential, procedures is for the artist to paint FAT over LEAN. Lean paint has less oil content than fat paint. Thinning the paint with turpentine results in a leaner, faster drying and toothy surface for subsequent paint layers. Sketches and underpaintings should be done with a lean paint mixture. When an artist paints a lean, fast drying layer over a fat, slow drying layer tension is created. The fat layer, if not completely dry, moves during oxidation and cracks the stiff, lean paint layer. Lean paint will slide or "crawl" over fat paint as it dries leaving an "alligator" pattern of cracks that greatly disrupts the composition and intended mood.

When the painting is thoroughly dry and complete in all details it must receive a protective coating before being placed into a frame. Oil paintings require four months to a year to be dry enough for varnishing while acrylic paintings can be varnished the same day they are completed. There are many varnishes on the market - some made for fine paintings and some made for furniture, floors, and boats. When necessary a picture varnish can be removed and a new coat reapplied without harming the painting. Wood varnish, on the other hand, cannot be removed without the use of harsh solvents and scraping. Varnish for paintings should be purchased from an art supply store - not a hardware store! A prerequisite for all artists' varnishes is that they must be easily removed without harsh chemicals or solvents. This means the chosen varnish must be soluble in turpentine or mineral spirits for natural resins or xylene or toluene for synthetic resins. Hard resin varnishes prepared in oil, such as copal and amber, should be eliminated as picture varnishes. Their strong, inflexible films can be a destructive influence, rather than the protective one it is intended for. Two commonly recommended varnishes are damar (natural, soft resin) and methacrylate (synthetic, acrylic resin). When the ravages of time, dirt and atmosphere render them fragile and inefficient they are easily removed with mild solvents. Under normal conditions a picture varnish should stand up structurally and aesthetically for at least 25 years. To summarize this important step in preservation: always varnish paintings so the varnish, not the painting, receives the brunt of all blemishes; use a soft natural (damar) or synthetic (acrylic) varnish that can be removed without harm; and apply one to several thin coats rather than one thick coat.

Framing is usually thought of as a decoration only but it is a major and vital step in the preservation of paintings. A well built frame stops the auxiliary support (stretcher) from warping thus eliminates the tears and cracking produced by the movement of a warping support. Many contemporary paintings merely have molding or trim tacked to the stretcher. This can be, at times, aesthetically correct but it is never structurally correct and should be rectified before hanging for permanent display. The frames inner measurement, or rabbet, should allow for some expansion and contraction of the painting. A painting should never be forced into a frame, trimmed to fit a frame, or attached by hammering nails through the stretcher and into the frame. Mending plates or "spring clips" should be placed over both the stretcher and the frame but only secured to the frame with screws. Reputable framers know, and use, sound framing techniques.

Most conservation needs are a consequence of two things - the touch of a well-meaning admirer and the myths related to art restoration. Painting restoration is an antique term which, to some, refers to the way artists used to completely refurbish paintings. The painting was not preserved but only made to look new again. Sometimes the painting was completely repainted covering up the artist's work. Painting conservation, today's term, refers to the restoration and preservation of the work with the greater importance placed on preservation. This is accomplished by careful examination and testing before any cleaning and repairs are made and, when retouching is necessary, it is applied to the damaged area only. Whichever term is used, restoration or conservation, the essence is, or should be, the same.

The rubbing of linseed oil over an old, dry, cracked painting to revitalize it is one of the most destructive myths in use today. Linseed oil does not penetrate, soften or revitalize dry oil paint. It merely streaks the grimy surface and dries to a heavy, hard, discoloring layer over a dirty, cracked, discolored layer. In summary, preservation starts with the purchase and preparation of quality materials; the knowledge and skill of the artist; a protective varnish coating; sound framing methods; climate controlled atmosphere; and, above all, the thoughtful consideration of both artist and collector. Preservation is an ongoing, never ending process that is the responsibility of the artist, the collector, and anyone who handles art

How to Examine an Antique Painting

by   Peter Kostoulakos

Download my 17 page article

As published in the Journal of Advance Appraisal Studies - 2011