MATERIALS & METHODS
Paper - Works on Paper
Dolloff, Francis W. and Roy L. Perkinson. How to Care for Works of Art on Paper. Museum of Fine Arts, Boston. Fourth Edition. 1985
The exact style and color of a frame is a matter of personal taste, but the advice of a competent framer will be helpful, since there are a number of hazards. A picture can be damaged by placing it directly against a wooden back. Disfiguring stains often result from resins exuded by the wood itself. If several pieces of wood are used, the openings between them allow pollutants in the air to attack and discolor the picture [see Figure 3]. An enterprising individual in the late nineteenth century patented a variation on the wooden back that consisted of thin, narrow strips of wood laminated between two pieces of paper. He might have second thoughts about his invention now if he [p. 30] could see how many pictures it has disfigured. Even if there are no signs of staining, any picture with a wooden back should be opened to make sure it is properly protected with a piece of all-rag board.
Never place a picture directly against the glass, since glass easily condenses moisture and may cause the growth of mold. There is also a chance that the surface of the picture will stick to the glass, resulting in serious damage. A mat creates a "breathing space" between the picture and the glass and allows the picture to move in response to changing atmospheric conditions [see Figure 9]. If a mat is not considered desirable, as is sometimes the case with modern prints, the same protection can be provided by a strip of mat board cut sufficiently narrow that it will be hidden beneath the rabbet [inner edge] of the frame. Or acrylic plastic may be used instead of glass, since it is a better thermal insulator and will not condense moisture as easily as glass. [p. 31] Acrylic plastic is unbreakable and is available with colorless additives that filter out ultraviolet rays. It is particularly suitable for a picture that has to be transported or subjected to handling that might break the glass. The disadvantages of acrylic plastic are that it scratches easily and has a tendency to collect dust because of its inherent static electricity, which also rules out its use on unfixed pastel or charcoal drawings or paintings with flaking or powdery pigments.
To protect a picture from dust, dirt, and flying insects, seal the back of the frame with acid-free corrugated cardboard or styrofoam-filled board. Use nails to secure the board in place, not staples or glazier's points, which soon loosen and fall out. Especially fragile pastels or gouache paintings may be damaged by the shock of hammering the nails. The best method for these is to hold the back in place with metal or wooden braces secured with screws. Seal the gap between the backboard and the frame with gummed wrapping tape, which is permeable to atmospheric moisture and allows the frame to "breathe" and respond to changes in temperature and humidity. A completely airtight seal is neither possible nor desirable, since a significant drop in temperature would cause a dangerous buildup of humidity within the frame. It is better to control the conditions in the room where the picture hangs than to try to burden the frame with that responsibility.
When cleaning a framed picture, never spray the cleaning solution directly onto the surface of the glass. The liquid may run down inside the frame and stain the mat or cause a dangerous elevation of the humidity inside the frame. Apply the cleaner to the cloth instead.
Never allow the framer to cut or trim the margins of a picture. To do so may damage its aesthetic effect, destroy evidence of authenticity, and in general diminish its desirability and monetary value.
The back of a frame occasionally bears a label that is pertinent to the provenance or authenticity of the picture. If such a label is a document in its own right, it should be treated accordingly and properly protected. If it can be removed from the frame, it may be preserved in an acid-free envelope attached to the rear of the frame, protected from dust by flexible plastic sheeting [Mylar]. Or the label could be hinged into the mat itself.
If a picture is kept permanently framed, it is advisable to open and examine it periodically, about every ten years or so, to make sure that it is in good condition. Even if everything is satisfactory, the inner surface of the glass should be cleaned. It is surprising how much of a haze can develop on the inside of a picture glass within just a few years. Sometimes a "ghost" image of the picture appears on the glass, especially in the case of prints, apparently because of the [p. 32] transference of volatile components of the printing ink to the glass.
Pictures should never be framed between two pieces of glass, whether with or without a mat. This method of framing increases the danger of mold growth, and if an object hits the glass, it is likely to pierce the picture and both pieces of glass, thus causing considerable damage. If both sides of a picture or document must be visible, acrylic plastic should be used instead of glass.
Use of "nonglare glass" with a frosted appearance is not recommended. To function properly it must be placed directly against the picture, a practice that, as mentioned previously, should be avoided. If used with a mat, it tends to obscure the picture. Reflection on glass can be dealt with by appropriate placing of the picture in relation to the light or by using an optically coated nonreflective glass.
Pictures can be hung from molding with hooks and nylon line, which is nearly invisible. The local hardware or sporting goods store can supply line of the proper strength to support the weight of the picture. Another method is to use copper wire painted to match the walls, as is done in some museums. If there is no molding, the usual combination of picture wire, screw eyes, and hooks nailed into the wall will suffice for lightweight frames. A piece of adhesive tape wrapped around the middle of the picture wire will help to keep the picture from tilting. Picture wire exerts tension on each side of the frame, however, and may break apart the corners of heavier frames. They are best hung without wire from two separate wall hooks through the screw eyes. This method does not strain the frame, keeps it level, and gives safer support. Hold the picture against the wall in the desired position [level it with the help of another person ], press firmly against the frame, and move it slightly to one side. The screw eyes will leave light marks on the wall, which will help in nailing the hooks.
Gummed or self-adhesive hooks are useful as a temporary support for lightweight, expendable pictures, posters, and other decorations but are not safe for permanent hanging of framed pictures.
To judge by the frequency with which buckling of a picture is mentioned, it is one of the chief causes of concern for the owner. It does not in itself constitute a danger, however, since it is perfectly natural for handmade paper to show some slight degree of movement. If a picture appears to be absolutely flat, it may even be an indication that it has been mounted down. Excessive buckling, however, may be caused merely by too much pressure on the edges of a picture by either the mat or frame and can usually be corrected by the framer. Localized cockling, or puckering, may be caused by the presence of old tape, patches, or glue on the back of a picture, in which case [p. 33] the picture should be brought to a restorer for advice.
Under no condition should a picture be mounted down merely for the sake of removing a few waves or slight buckling, but, unfortunately, this is one of the most common practices today among less-experienced framers and ill-advised collectors. Even Rembrandts have fallen victim to being mounted down on cheap wood-pulp boards with carpenter's glue, photographer's heat-sealing tissue, and synthetic glues. Just as common is the gluing of watercolors onto brown kraft paper and pulling them tight as a drumhead across a wooden stretcher. This method of mounting should be avoided, because the wood resins and cheap paper will cause stains and the constant tension on the picture may weaken the fibers of the paper. In certain cases it may be necessary for the purpose of conservation to support a fragile or damaged picture by backing it with a handmade paper, but this operation should be done only by a competent restorer. Gluing pictures down indiscriminately is harmful, unnecessary, and diminishes the monetary and aesthetic value of a work of art. A picture that has been mounted down should be taken to a restorer for advice as to whether it can be removed from its backing. [p. 34]
[Dolloff, Francis W. and Roy L. Perkinson. How to Care for Works of Art on Paper. Museum of Fine Arts, Boston. Fourth Edition. 1985.]
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