A COMPLETE MANUAL TO THE CONSERVATION, DISPLAY AND RESTORATION OF PAPER
By Gordon Lewis, Senior Vice President and Director of The Fine Arts Conservancy.
Photo: Print by Willem de Kooning, After (left) and Before (right) severe water damage
Over a period of issues on The Clarion List, there will be a series of collectors’ guides to the conservation and display of art. These will appear in no particular order, and each type of art will have several parts to address all of the issues for that type of art. While all issues pertinent to a collector will be covered, they will not be sequential, but rather there will be an element pertinent to each type of art, but space compels us to divide each topic into several editions. Typically, we will address the most critical element (conservation and restoration first) with other elements, such as display, storage, and care, etcetera, to be covered in future issues. We will also discuss framing, appraisal and collection management. So this first is about paper, with paintings, objects/sculpture and outdoor sculpture to follow with part 2 of paper in this lineup as will be part 2 of the other topics.
PART #1: DAMAGE AND RESTORATION
For many collectors, there is no greater joy than a great work of art on paper, from old master drawings to the remarkable technology of today’s fine art print makers. Many experts feel the true proficiency and skill of an artist lies in his drawings, which reveal the artist’s inherent ability on an unforgiving surface that accepts little or no change, unlike paintings, which can be reworked forever.
The Chinese, in 105AD, first invented paper during the T’ang Dynasty; in fact, today one can see written inventories, on paper, of the T’ang emperors’ possessions in the National Palace Museum in Taipei. However, our first knowledge of paper as an art medium appears in Chinese woodblocks somewhere between the 6thand 9th Centuries. Although papyrus was made for many centuries before paper was invented.
Printing and drawing on paper, in Europe, appears to have emerged at about the same time as the beginning of papermaking, in 1390.
Paper conservation requires a mastery of skills and a level of technical ability unique to art; there is no margin for error.
For all of its beauty, art on paper is among the most fragile of art, and both the most demanding and unforgiving medium for conservation. Of all of the areas of conservation, paper is the only one where less is done now than twenty years ago. In the intervening years, we have found that earlier attempts at bleaching (to return the paper itself to its original light color) have actually resulted in more damage over time than we had known. As advanced chemistry has entered the art arena, we have found that bleaches cannot be successfully removed from paper; a free radical of chlorine attaches itself permanently to the cellulose paper fibers and continues to deteriorate the paper – eventually, over years, resulting in collapse of the paper fiber.
Because of its inherent fragility and the delicacy of many of the inks, watercolors and other mediums used to create the images, paper is less robust than most art mediums; particularly because natural light and some artificial lights, such as fluorescents and quartz halogens, will cause fading which cannot be restored. Once the color changes, there is no way to recover the original color. For all practical aspects, these pieces are ruined and, in most cases, are either badly devalued or without value at all.
However, for all of that, what can be accomplished on damaged paper in the hands of a gifted conservator is remarkable. Many of the problems we see (other than fading) can be successfully remediated. Again, like paintings, the collector is in the ideal position to note any changes or damage in paper. Some of the damages we typically see (other than damage caused by framing – which we will explore below) are:
FRAMING DAMAGE: The majority of the damage we see is, by far, from old, poorly done, or inadequate framing. All framing should have acid free materials inside; Japanese paper hinges skillfully adhered with starch paste to mount the work. Ultraviolet filtering glazing (glass or acrylic) is critically important - especially in South Texas and tropical Florida. Most residents do not realize how much farther south they are toward the equator - and its direct correlation to the amount of ultraviolet in our light. They are on the 27th parallel; that is 400 miles south of Cairo, Egypt with all it implies. ALL NATURAL LIGHT, WHETHER DIRECT OR INDIRECT, WILL FADE ART ON PAPER. There is no such thing a gentle natural light All of these issues in framing, which constitutes museum quality framing, will be explored in depth in a future article, but, in the meanwhile, examples of master framing using period frames, contemporary and replica period frames are on our website.
WATER OR HUMIDITY DAMAGE: We see this type of damage frequently with attendant rippling. Usually, we treat rippling by placing the paper into a humidity chamber until it becomes flaccid, and then drying it on a vacuum suction table, with enough suction to keep the paper perfectly flat while air, drawn through the paper dries it without crushing the medium into the paper. Previously, conservators dried the paper under glass sheets and weights. While this technique is good for some image mediums, such as some prints, it will drive more fragile mediums, like pencil, some inks, watercolors and pastels down into the paper rather than keeping them on the surface. Another drawback to weighted drying is that the weights crush the paper surface, flattening the “fleur” of its surface texture. The artist carefully selected specific paper to enhance his work; crushing it by flattening diminishes major elements of the work, losing major elements of its beauty.
MOLD/MILDEW, FOXING AND STAINING: First, mold is killed and the mold odor removed, in a chamber using a hydroxyl generator. Stains used to be removed by bathing the paper (if the medium allows it). Today we use a hydroxyl generator in an enclosed space to both kill the mold and remove mold odor without any physical change to the paper or media. Stains are then removed using a gel infused with the necessary solvents or chemicals. This is much less invasive than bathing.
HOLES AND MISSING PAPER: This type of damage is dealt with in several ways, including the seamless integration of a similar paper to the original or actually casting paper slurry into the missing area. There are a number of photos of these repairs, and treatment of other damages, on our website.
TEARS AND CUTS: Tears and cuts can be mended in a number of ways, and the method employed is dictated by the nature of the damage. Repair techniques range from carefully reweaving the paper fibers together under a microscope to having to line the piece completely with another, compatible piece of paper adhered in its entirety to the rear of the original work, known as “lining”. Obviously, lining is a last resort, since the credo of any treatment on any work of art is “minimal intervention.”
BROWNING/YELLOWING OR ACID BURN: Burns are the result of poor quality materials in framing or storage. This results either from the paper being made of wood pulp rather than rag, or proximity with other materials made of wood (wood pulp based framing or storage materials or even wooden drawers). This damage can be so severe that it embrittles the paper to the point of the paper collapsing. There is a point at which the piece cannot be saved, however in anything less than total collapse, much can be done. The root cause is acid, specifically lignin acid, inherent in inexpensive framing materials, such as mats and the rear boards upon which the art has been hinged. Several approaches are successful: neutralizing the acid chemically or removing the acid in an aqueous bath, if the medium is appropriate. Residual staining is removed as described several paragraphs above.
MAT BURNS: These type of burns generally are noticeable as tan or browning lines on areas of the artwork adjacent to the mat. These are a variant of acid attack and treated similarly. Lignin acid attacks paper in two ways: it migrates by direct contact with the art, and it has a vaporous form that can fill a frame with acid vapor, attacking the art overall.
PIGMENT LOSS: Pigment loss is frequent in gouaches, some inks, and watercolors. Standard treatment for this is retouching, similar to what is done in paintings, although stabilization of the other pigments is sometimes necessary if it is cracking or powdering.
INSECT DAMAGE: This type of damage is not unusual; there are 18 varieties of insects that love to eat paper and wood. These attacks often appear as holes in the paper; small craters gouged out of the surface, or small raised brown specks. Of course, foremost in treatment is fumigation to assure that any insects, eggs and larva are dead. Subsequent treatment is the same as described above to fill holes and retouch pigment loss.
TAPE AND ADHESIVE STAINS: The use of self-adhesive tapes to hinge art works is lethal. The adhesive migrates through the paper creating a permanent stain with little or no hope for removal. These stains cannot be removed unless they are caught before the adhesive has set into and completely migrated through the paper to the point where the stains emerge on the front. But often the stain can be diminished cosmetically. In most cases, tape stains create a serious loss of value.
There are numerous other problems besetting paper, but most can be successfully restored. They include:
- Creasing, handling cockles, deep folds, and wrinkles and rippling.
- Surface dirt, dust, soot, and foreign matter clinging to the surface.
- Abrasions, scuffs, shiny marks, scratches and scratches with pigment loss.
In future articles, we will discuss conservation framing and other paper issues in depth, but my next article will focus on paintings.