What Every Art Buyer Should Know
Why is Good Craftsmanship Important?
What is Good Painting Technique?
How a Painting is Put Together
The Anatomy of a Painting
When looking at a painting, most viewers are so focused on the subject the artist has portrayed that they forget the painting, like any handcrafted product, is a physical object comprising many different materials. Considering that the choice of which materials to use and the way they are put together are what determine the stability of the painting as a whole, one would expect the potential buyer to be at least as concerned, if not more so, with the physical side of the painting as they are with the subject itself.
Connaisseurs pride themselves on their knowledge of a painter's subject matter, but are at the same time often completely ignorant of the materials the artist used to create his imagery. The physicality of a work of art may not be the focus of the artist or the connaisseur, but it is certainly of equal importantance, and it is surprising that most viewers and artists alike are unconcerned with what amounts to at least half of the nature of a work of art. For the artist, such disregard is an unacceptable lack of professionalism. For the buyer, who does not always have access to such information, it is more or less just a dangerous oversight in terms of making an investment.
Those who intend to buy paintings should at the very least have a basic knowledge of their fundamental components, as well as a simple understanding of what to look for to insure that they are not investing in something that is destined for an untimely oblivion. Even a few simple rules of thumb applied at the time of choosing one's purchase can help to avoid costly repairs and service down the road.
The following two sections are devoted to providing the reader with just that. The current section will provide a brief description of the basic components of paintings and how they should be employed to ensure soundness. The next section, What to Look for When Buying a Painting, will provide a checklist the reader may use to examine paintings for some of the most common and easily avoidable flaws that artists often unknowingly build into their works. After reading these two sections, the average reader will be much better equipped to choose their painting investment without fear of problems from material deficiencies cropping up afterwards.
Afterall, if you can't depend upon today's artists to create sound works of art on their own, you can at least give them incentive to do so by denying them your patronage. The more knowledgeable the patron is of good technique, the higher degree of excellence the artist must employ in production of his work. The result is a greater benefit on the part of both parties.
The Role of the Stretcher Frame
Aesthetic considerations aside, a painting is a construction of many superimposed layers of materials. Often each layer represents a mixture of several parts rather than a single substance. The quality of each part and the care in its application contributes to the painting's long survival or early deterioration.
First, there is the stretcher frame for paintings that are executed on a fabric support. The stretcher frame is a wooden construction over which the fabric is stretched and secured, so that the fabric will form a taut and even surface upon which paint can then be applied...It should be constructed with mitred corners and with a rising outer edge or bevel, high enough to prevent the fabric from resting on the frame.
What this means is that as little of the fabric as possible should touch the frame. This is achieved by creating a short lip that runs around the outer perimeter of the frame on the side where the fabric surface is stretched. When the fabric is stretched over the frame, it will then be suspended above the body of the frame by the lip. If the fabric is allowed to rest on the wooden frame, it will not be able to "breathe" properly, which can lead to rotting of the fabric and frame. Suitable mass-produced stretcher bars can be purchased for a small sum in nearly every art supply shop. But many uneducated artists choose to bypass this necessary step in favor of cheaper strainer frames (non-expandable with no lip) they construct themselves from typical, flat pieces of wood. These self-constructed frames are a danger to the longevity of the painting because they have no lip (which means a high amount of contact between the fabric support and the frame), and cannot be expanded to take up slack in the fabric to accommodate for inevitable environmental changes.
It should also have provisions for future expansion in height and width when this becomes necessary, as it most certainly will. All too often stretcher frames are actually "strainers", that is, the frame on which the artist has stretched his fabric has no slots in the corners for inserting wooden wedges called "keys". Instead, it is a rigid frame with the corners often nailed or glued together. As the fabric support expands and contracts, and becomes slack and taut with changes in relative humidity (and unless the painting is housed in an air conditioned atmosphere, it constantly undergoes such dimensional changes), the threads of the fabric are stretched and extended. When this happens it is necessary to take up the slack in the fabric to avoid inducing cleavage and losses in the paint film and to avoid the formation of disfiguring draws in the fabric along the edges and the corners of the painting. This is easily and most economically done by merely expanding the stretcher frame.
...When there is no provision for expanding the frame because the fabric has been stretched on a "strainer", one either neglects to take up the slack by restretching, or one is faced with the time-consuming job of removing the painting from the strainer and restretching it on a proper stretcher frame. The latter process involves a certain amount of unavoidable wear and tear on the painting and some extra expense. All this can and should be avoided in the first place by employing expandable type stretcher frames instead of stretcher frames that might more accurately be called strainers.
Depending on size, paintings larger than thirty by thirty-six inches should have one or more crossbars to equalize the tension in the fabric and to prevent bowing of the stretcher frame. These crossbars should not be nailed to the stretcher frame. They should tongue- and-grooved with provisions for expanding, just like the rest of the frame. Paintings of large dimensions should also have suitably thick frames. A painting of six by eight feet in size should have a frame that is at least an inch thick and between four and six inches in width. Even the smallest paintings should never have a frame of less than half an inch in thickness.
In assembling the stretcher frame be sure the mitred corners join together perfectly so that the assembled frame is square. Also be sure the bevelled stretching edges are level at the corners. Doing so will reduce strain and uneven tension on the fabric and ensure a uniform distribution of pressure across the surface of the fabric. It will also prevent unnecessary tears which may result from the fabric coming into prolonged contact with a rough or pointed edge.
Choosing a Fabric Support
In choosing the type of fabric on which to paint, the choice is usually between linen, cotton, or a mixture of the two. Linen is by far the most desirable fabric support for oil painting. It is stronger and much less reactive to moisture, therefore more durable and more stable than cotton. Fabric that is highly reactive to moisture will expand and contract in size with changes of humidity, which applies a great deal of stress to the brittle layer of paint that has been applied to it. Since the paint layer is unable to expand and contract with the fabric, this will cause premature cracking of the paint layer.
Fabric composed of a mixture of cotton and linen is definitely to be avoided because their difference in reaction to moisture results in unequal expansion and contraction of the threads, causing a correspondingly unequal tension in the paint film and eventually, paint damage. Cotton fabric may be good enough for student work, but it is not of satisfactory quality for the professional artist concerned with the durability of his work.
Jute or burlap fabrics also have no place in permanent painting. Their extremely poor aging characteristics cause them to become very brittle, thus losing strength in a comparitively short time. Their loose, open weave is an additional fault to consider in rejecting these fabrics, for they can hardly supply sufficient support to the priming or general paint film. Keying out such fabrics is hazardous since they may easily tear away from the stretcher frame or from the paint film.
...the extreme porosity of these cheap fabrics presents serious limitations to the conservator of paintings when the need arises to preserve them. It is often impossible to employ first choice methods and materials without running the risk of altering permanently the artist's conception. Since the goal of the conservator is to preserve the work of art and to prevent it as much as possible from undergoing changes which falsify the artist's conception, the need to compromise on a choice of restorative materials and methods of treatment is highly frustrating. In such instances the artist's own choice of faulty materials prevents the proper preservative or restorative treatment of his work.
Stretching a Fabric Support
In stretching the fabric on its frame at least three points should be remembered:
1. Align the warp and weft threads so that they are parallel to the top, bottom and sides of the stretcher frame and maintain this alignment at all times during the stretching procedure.
2. Use rust-free nails or staples, such as those of copper coated steel, to avoid rust stains and subsequent rotting of the fabric. Use intervals of approximately one inch, driving the nails all the way in so that the nailhead is in contact with the fabric. In stretching the fabric the mistake is often made of increasing the intervals between nails when the painting is a large one. This is an unsound practice. The larger the interval between the nails, the more exaggerated becomes the thread distortion when the stretcher frame is keyed out. When large intervals bewteen nails exist and the fabric becomes taut as a result of changes in relative humidity there is also an unequal strain on the paint film as well as on the fabric.
3. Allow for an excess of fabric to be folded over the back of the stretcher frame...This is to allow gripping of the fabric in anticipation of the need to restretch the painting at a later date. It will prevent a great deal of wear and tear and expense later on. When this need has not been anticipated and no excess canvas is available to grip and pull, the painting has to be "strip-lined" first before it can be properly restretched. That is, once the painting has been removed from the stretcher frame, the extra lengths of linen fabric required all along the four edges of the painting must be attached with an appropriate adhesive. This usually requires skill, time and expense. Obviously it is wiser to provide a few extra inches of fabric on all four sides when first measuring the fabric for stretching..
The Need to Coat the Fabric Support with Size
If the stretched fabric is natural linen...and the painting medium to be employed is the traditional linseed oil, it will first require a coating of glue size before oil paint is applied to the fabric. Many avant-garde artists have omitted this important step in the construction of their paintings. They may thereby have ensured a shorter working time for themselves but, regrettably, the lifetime of their work of art has been shortened.
The important function of the size is to act as an isolating layer between the natural linen fabric and the oil paint. For if the oil in the paint is absorbed by the linen it will have a deteriorating effect, shortening the life of the linen. Also, by absorbing oil from the paint layer, it reduces the ratio of oil-to-pigment in the paint which can lead to flaking and cracking of the paint layer.
The size, which is a solution of gelatin or rabbit skin glue dissolved in water, does not absorb oil and thus prevents any contact between the linen fabric and the oil in the paint. Therefore, if durability is a concern of the artist when employing the traditional oil medium, it is absolutely necessary to apply a glue sizing to the linen fabric before any painting is begun.
Very frequently with paintings executed on unsized and unprimed fabric the artist allows the natural unpainted surface of the fabric to act as an integral part of the design. It is almost impossible to preserve the original appearance of such areas. They are very susceptible to soiling and are almost impossible to protect with varnish without changing their color.
"Rich on Lean," a Basic Rule of Painting
"Rich on Lean" is a concept that is also often called "Fat on Lean". In Dr. Pomerantz's book, he uses the term "Fat on Lean", but in order to keep the terminology at RationalArt.com consistent, we have replaced the term with "Rich on Lean" in all cases.
It is difficult to understand why so many of our best contemporary artists continue to jeopardize the durability of their artistic creations either through ignorance or neglect of, or indifference to, the most basic rule of sound craftsmanship in painting: always paint rich on lean. It is of the utmost importance never to paint lean on rich.
Perhaps it would help to express this basic rule of painting in another way. "Always paint rich on lean" means always paint a more slowly drying film over a faster drying film. Visualize this by thinking in terms of the last applied film being more flexible than the paint film underneath. Yet another way to clarify this basic rule is to think of the need for including a little more oil medium in the last application of paint than was included in the underpaint just covered, or to make sure not to thin with turpentine the last applied layer of paint any more than the underlayer was thinned.
When mixing paint, an artist will often add turpentine to his colors in order to make them flow easier and dry faster. The result is a thinner, less flexible layer. Similarly, he will often add additional linseed oil to the colors to make them thicker, creamier, glossier and dry more slowly. The result in this case is a more flexible layer. If an artist violates the rich on lean rule, he creates a dry, brittle layer lying on top of a moist, flexible layer. The result is much like a cup of pudding left out on the counter over night. The quickly drying "skin" on top cannot expand and contract at the same rate as the wet pudding underneath, and inevitably large cracks form on the surface as the pudding below dries.
The disfiguring drying cracks which unintentionally expose the underpaint and create a dominant motif in numerous areas of the painting, have almost become the hallmark of the Abstract Expressionist and Action painter of today. This is a direct result of breaking the above cardinal physical law. It seems ironic tht the very artists who place a premium on immediacy of effect and on spontaneity of expression, should find their lack of control of materials defeating their very goal, since their designs continue to change on their own, and in spite of their wishes, after they have completed their last paint stroke.
"RICH ON LEAN" should be written on the walls of every artist's studio.
Coating the Paint Layer with Varnish
Once a painting has been completed it is customary to coat its surface with a layer of varnish. From the point of view of function, varnish is intended as a colorless, temporary, protective coating applied over the painting to guard against discoloration of the paint film due to accumulations of grime, and to protect against the harmful effects of the atmosphere. It is meant to be removed and replaced when it no longer adequately fulfills any of these functions. It is also intended to restore the original color relationship in the design when colors have sunken in or have become mat in spite of the artist's wishes.
It is very important that an oil painting have a protective layer of varnish. Without it, harmful effects will be received by the paint layer itself, causing permanent damage to the work of art. Replacing the varnish layer is a relatively easy task for a professional restorer, and the application of the varnish is a quick and easy process for anyone.
The presence of varnish on the surface of a painting will give it an even glossy sheen, and tend to flatten out any textures present in the paint layer itself. When abiding by the rich to lean rule, it is common for paintings to have a glossiness of their own, and so applying varnish rarely distorts any of the original design. If the colors of a painting look mat, dead or dry, there is a good chance that it has not been properly varnished, or even received a protective layer at all. Naturally, such neglect is to be avoided.
Over the course of 50 to 100 years, natural varnishes will tend to become somewhat yellowed in their color. This accounts for the "old-looking" golden hue of many museum pieces. A browning of the colors can also occur due to the accumulation of dust and grime on the surface of the varnish. This brownish coloring is not consistent with the original designs of the artist. Luckily, by simply having the varnish removed and replaced, the original look of the painting can be restored for another 50 years. Without the presence of varnish, the grime will accumulate on the paint layer itself, which can cause a permanent change in the original colors of the painting.
Unfortunately, many artists today use the application of varnish as a means of "intensifying" their colors or increasing their richness. This can be a dangerous practice. Highly absorbant paint layers are usually an indication of "leanness", or low oil content in the layer. This means that the surface of the paint layer will be rough instead of smooth on the microscopic level. When the varnish is later removed to be replaced, particles of the paint layer are prone to come off with it, causing damage to the painting. The proper way to create richness of color in a painting is by making sure that the upper layer of paint has a high oil content. Therefore, it will have a lower absorption and a smooth surface and will not incur any damage when the varnish needs to be removed. It also safely achieves the glossy surface appearance most painters prefer, without resorting to the dangerous practice of "glossing up" a matte-colored surface with a thick application of varnish.
Another important consideration is the drying time a painting needs before applying varnish. Paintings with relatively thick paint will need a minimum of one year to dry completely. Coating the painting with varnish before that time can prevent the painting from drying properly and have damaging effects. Paint can become dry to the touch in a matter of days or weeks, but that is not a reliable indication of its actual dryness. An artist should always allow sufficient time for a painting to dry before varnishing it.
The Picture Frame
Most paintings are displayed inside a picture frame. The picture frame is not only an aesthetic enhancement in the presentation of the painting, it also has a very practical purpose.
Without a picture frame, the painting could only be hung by suspending it from its own stretcher frame. This is a bad practice. By doing so the stretcher frame is made to bear the entire weight of the painting. Over time, this can cause the stretcher frame to distort in shape and thus put uneven stress on the painting that it bears. The current practice of framing a picture by attaching thin strips of wood to its outer perimeter is not a sufficient means of displacing the weight from the stretcher frame and should therefore be avoided. A painting should always have a frame that is substantial enough to bear the entire weight of the painting.
The picture frame also serves as a means of protection for the painting whenever it is handled. The surface of the painting itself should never be touched. With an adequate frame, a painting can be transported easily without endangering it.
Screws and not nails should always be used in the construction of a frame. Nails will allow joints to slip and move, while screws will keep them firmly in place. Also, the only way to insert a nail is by hammering, which will send dangerous shock-waves through the painting, possibly resulting in future damage--much of which may not even become visible until the painting has aged for several years. Only screws can be inserted safely without the need of hammering. Be sure to always use screws instead of nails.
The framer should be instructed by the artist to provide extra space on all sides of the stretcher frame in anticipation of the need to key out or to expand the stretcher later. If this extra space is not provided, it will be at the expense of the painting's safety and the artist's or owner's pocketbook. All too often the painting is pressed into the inadequate space of its frame, compressing it, and creating "draws", buckling of the support and eventual flaking of paint, a costly affair from many points of view. The framer should provide approximately one-half inch of space on all sides of the stretcher frame. The painting can then be secured by inserting balsa wood shims between the stretcher and the picture frame.
It it very important that the surface of the painting does not come in contact with any part of the frame. If it does, abrasion may occur, or moisture may be trapped resulting in damage. This can best be avoided by simply screwing aluminum strip molding to the sides of the stretcher frame, allowing the molding to extend slightly above the surface of the painting. This way, when the painting is inserted into the picture frame only the strip molding will come into actual contact with the frame.
The final consideration in framing is to be sure that when the painting is to be shipped, transported or moved, a protective backing is screwed to the rear of the frame. This will protect the painting from being touched or punctured from the rear by careless handlers. This backing should, however, be removed when the painting is displayed to avoid the possibility of moisture being trapped in the space between it and the canvas.
What to Look for when Buying a Painting
