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The conservation and restoration of woodblock prints, is the process of caring for and repairing images made from a specific printing process involving using wooden reliefs to stamp or imprint an image onto paper. The process of creating woodblock prints as Asian examples are known, or woodcuts as Western examples are called, has been known for many centuries, and many older prints have experienced aging and deterioration of the paper and colorants used.
Woodblock prints from Japan are commonly printed on kozo , paper made from mulberry tree fibers. Many pigments were derived from organic materials. For example, some blue hues were derived from dayflower petals. Other inorganic colorants, such as red lead, were also used. [1]
Fibers of Chinese woodblock prints come from five different plant groups: hemp, bark, rattan, bamboo, and grass. Fibers from these different groups were often combined, based on which plants were locally available. [2]
European woodcuts such as Italian chiaroscuro woodcuts, were generally made of three materials: paper, pigment, and a pigment binder. Paper was generally thin, because woodcuts were made in larger batches, and were relatively cheap. The pigments were composed of both light-stable inorganic materials such as metals and earth compounds as well as organic colorants such as indigo. Both of these respond to environmental conditions different, and require different conservation treatments depending on the chemical composition. Binding agents for the pigments were oil-based and used to dry the inks more quickly. They were made from materials such as linseed oil and conifer resin. [3]
Light has been known to fade pigments in woodblock prints, such as the colorant dayflower blue, found in many Japanese woodblock prints. Ultraviolet is the most damaging wavelength, yet even infrared can cause damage, especially because it also heats up prints when they are exposed to infrared waves. [4]
Paper and pigments are both very sensitive to changing humidity levels. If relative humidity falls lower than 35 percent, the paper can dry out and become brittle. If it reaches higher than 65 percent, the paper can become distorted. Furthermore, certain pigments can become more translucent in higher relative humidity. High fluctuations in relative humidity may cause the paper to experience stresses that could cause it to crack. Humidity can also aid the growth of pests and mold. [4]
Heat can accelerate the rate of mechanical stresses in organic materials and cause the structure to become brittle or unstable. [4]
Pollutants found in the air can interact with materials on woodblock prints and cause them to deteriorate at a quicker rate. For example, when exposed to sulfur-containing gases, red lead pigments will turn a metallic brown/black color. [1]
Insects and pests can destroy woodblock prints by eating through the paper or leaving droppings that stain the paper. A common cause of holes in Japanese woodblock prints is the deathwatch beetle ( Xestobium rufovillosum ). These beetles were commonly found in wood used to build furniture in the Edo period. Woodblock prints that were stored on bookshelves, or other furniture infested with these beetles, also became infested themselves. [5]
Preventive conservation, or collections care, is a way of preventing deterioration of materials by reducing agents of deterioration. A good integrated pest management system as well as an HVAC system that filters for common pollutants have been known to reduce the damage woodblock prints receive. [4]
The paper of woodblocks are often made of wood fibers and may react to non-archival quality storage materials. For example, if stored in paper folders, the prints can become acidic. Using acid-free storage materials can prevent these acidic processes. Storage materials such as folders or boxes can also prevent light from reaching the print, and further reduce damage to light-sensitive materials.
Ultraviolet-filtered, Plexiglas-glazed frames do little to protect woodblock prints from light damage over time. Museums often limit the display of woodblock prints, such as not exposing them to light for more than three weeks at light levels of 50 lux and keep relative humidity at 50 percent ± 5 percent. It is recommended to slowly acclimate prints to any difference in temperature. [4]
One method, called a blotter wash, can help to remove stains. This process involves applying a solution (such as a mixture of hydrogen peroxide and water) onto the areas affected by stains, spray rinsing the print in order to rinse off the solution, and then blotting it dry. [6] Many processes for removing stains could be highly detrimental to the paper, the pigment, or both. Water washing techniques such as immersion, floating, or suction table may cause the ink to run. Some organic colorants may even dissolve when exposed to water. [3]
Holes should be repaired using infilling. This is the process of adhering a separate piece of paper over the holes. Oftentimes adhesives are added that can be easily removed.
Demounting is the process of removing a print from the mounting material. This is often done because older mounts were usually made from acidic paper materials that can deteriorate the paper or fade colorants. Mounts are usually adhered to prints through adhesive agents that can cause yellow distortions on the paper. [7]
Dry flattening the paper of a print can sometimes remove signs of cockling, creasing, or wrinkling, In this process, the print is laid flat on a surface, and the weight of another object is used to add even pressure across the print. Sometimes flattening can be unnecessary, such as when storing items in a folder may be suitable instead. [8] Humidity flattening techniques often involve using humidity to help flatten paper objects; however, this technique can cause further damage to prints that have water-soluble colorants.
The Martyrdom of Two Saints from the Los Angeles County Museum of Art is an Italian chiaroscuro woodcut by Antonio da Trento that had cuts in the support. When conservators looked more closely at this artwork in 2016, they also saw unusual discolorations that proved that newer materials were used to conserve the piece in the past, and the added colorants faded at a much slower rate than the original colorants, leaving much darker stains. In order to restore da Tento's print, conservators infilled the support with new paper and masked the newer overpaint with pigments that more closely matched the rest of the print's colors as seen today.
Two Beauties under a Cherry Tree is a pillar print, a tall and narrow print used to hang in front of traditional Japanese pillars. It is housed at the Library of Congress, and underwent conservation in 2012 for the exhibit, Sakura: Cherry Blossoms as Living Symbols of Friendship. This print was brittle, acidic, discolored, and tearing due to light and pollutants exposure as well as a previous restoration with acidic materials. When it underwent conservation treatment, the print's previous mount was stripped. The print was washed in a calcium solution that reversed some yellow discoloration. In addition, an oxidizing solution was added to red lead colorants that had turned black. [9]
Ink is a gel, sol, or solution that contains at least one colorant, such as a dye or pigment, and is used to color a surface to produce an image, text, or design. Ink is used for drawing or writing with a pen, brush, reed pen, or quill. Thicker inks, in paste form, are used extensively in letterpress and lithographic printing.
Printmaking is the process of creating artworks by printing, normally on paper, but also on fabric, wood, metal, and other surfaces. "Traditional printmaking" normally covers only the process of creating prints using a hand processed technique, rather than a photographic reproduction of a visual artwork which would be printed using an electronic machine ; however, there is some cross-over between traditional and digital printmaking, including risograph.
Print permanence refers to the longevity of printed material, especially photographs, and preservation issues. Over time, the optical density, color balance, lustre, and other qualities of a print will degrade. The rate at which deterioration occurs depends primarily on two main factors: the print itself, that is, the colorants used to form the image and the medium on which image resides, and the type of environment the print is exposed to.
Hand-colouring refers to any method of manually adding colour to a monochrome photograph, generally either to heighten the realism of the image or for artistic purposes. Hand-colouring is also known as hand painting or overpainting.
The conservation and restoration of photographs is the study of the physical care and treatment of photographic materials. It covers both efforts undertaken by photograph conservators, librarians, archivists, and museum curators who manage photograph collections at a variety of cultural heritage institutions, as well as steps taken to preserve collections of personal and family photographs. It is an umbrella term that includes both preventative preservation activities such as environmental control and conservation techniques that involve treating individual items. Both preservation and conservation require an in-depth understanding of how photographs are made, and the causes and prevention of deterioration. Conservator-restorers use this knowledge to treat photographic materials, stabilizing them from further deterioration, and sometimes restoring them for aesthetic purposes.
With respect to cultural property, conservation science is the interdisciplinary study of the conservation of art, architecture, technical art history and other cultural works through the use of scientific inquiry. General areas of research include the technology and structure of artistic and historic works. In other words, the materials and techniques from which cultural, artistic and historic objects are made.
The conservation and restoration of parchment constitutes the care and treatment of parchment materials which have cultural and historical significance. Typically undertaken by professional book and document conservators, this process can include preventive measures which protect against future deterioration as well as specific treatments to alleviate changes already caused by agents of deterioration.
The conservation and restoration of textiles refers to the processes by which textiles are cared for and maintained to be preserved from future damage. The field falls under the category of art conservation, heritage conservation as well as library preservation, depending on the type of collection. The concept of textile preservation applies to a wide range of artifacts, including tapestries, carpets, quilts, clothing, flags and curtains, as well as objects which "contain" textiles, such as upholstered furniture, dolls, and accessories such as fans, parasols, gloves and hats or bonnets. Many of these artifacts require specialized care, often by a professional conservator.
The conservation and restoration of illuminated manuscripts is the care and treatment of illuminated manuscripts which have cultural and historical significance so that they may be viewed, read, and studied now and in the future. It is a specialty case of the conservation and restoration of parchment within the field of conservation and restoration of books, manuscripts, documents and ephemera.
The conservation and restoration of books, manuscripts, documents, and ephemera is an activity dedicated to extending the life of items of historical and personal value made primarily from paper, parchment, and leather. When applied to cultural heritage, conservation activities are generally undertaken by a conservator. The primary goal of conservation is to extend the lifespan of the object as well as maintaining its integrity by keeping all additions reversible. Conservation of books and paper involves techniques of bookbinding, restoration, paper chemistry, and other material technologies including preservation and archival techniques.
The conservation and restoration of Tibetan thangkas is the physical preservation of the traditional religious Tibetan painting form known as a thangka. When applied to thangkas of significant cultural heritage, this activity is generally undertaken by a conservator-restorer.
The conservation and restoration of frescoes is the process of caring for and maintaining frescos, and includes documentation, examination, research, and treatment to insure their long-term viability, when desired.
The conservation and restoration of flags and banners is the process by which conservators work to preserve and restore flags and banners from future deterioration and damage. As a part of Conservation of Textiles, flag and banner conservation require the care of a skilled and well trained textile conservator, specifically trained in historical materials.
The conservation and restoration of feathers is the practice of maintaining and preserving feathers or featherwork objects, and requires knowledge of feather anatomy, properties, specialized care procedures, and environmental influences. This practice may be approached through preventive and/or interventive techniques.
Conservation-restoration of bone, horn, and antler objects involves the processes by which the deterioration of objects either containing or made from bone, horn, and antler is contained and prevented. Their use has been documented throughout history in many societal groups as these materials are durable, plentiful, versatile, and naturally occurring/replenishing.
The conservation and restoration of paintings is carried out by professional painting conservators. Paintings cover a wide range of various mediums, materials, and their supports. Painting types include fine art to decorative and functional objects spanning from acrylics, frescoes, and oil paint on various surfaces, egg tempera on panels and canvas, lacquer painting, water color and more. Knowing the materials of any given painting and its support allows for the proper restoration and conservation practices. All components of a painting will react to its environment differently, and impact the artwork as a whole. These material components along with collections care will determine the longevity of a painting. The first steps to conservation and restoration is preventive conservation followed by active restoration with the artist's intent in mind.
The conservation and restoration of film is the physical care and treatment of film-based materials. These include photographic film and motion picture film stock.
The conservation-restoration of panel paintings involves preventive and treatment measures taken by paintings conservators to slow deterioration, preserve, and repair damage. Panel paintings consist of a wood support, a ground, and an image layer. They are typically constructed of two or more panels joined together by crossbeam braces which can separate due to age and material instability caused by fluctuations in relative humidity and temperature. These factors compromise structural integrity and can lead to warping and paint flaking. Because wood is particularly susceptible to pest damage, an IPM plan and regulation of the conditions in storage and display are essential. Past treatments that have fallen out of favor because they can cause permanent damage include transfer of the painting onto a new support, planing, and heavy cradling. Today's conservators often have to remediate damage from previous restoration efforts. Modern conservation-restoration techniques favor minimal intervention that accommodates wood's natural tendency to react to environmental changes. Treatments may include applying flexible battens to minimize deformation or simply leaving distortions alone, instead focusing on preventive care to preserve the artwork in its original state.
The conservation and restoration of photographic plates is caring for and maintaining photographic plates to preserve their materials and content. It covers the necessary measures that can be taken by conservators, curators, collection managers, and other professionals to conserve the material unique to photographic plate processes. This practice includes understanding the composition and agents of deterioration of photographic plates, as well as the preventive conservation and interventive conservation measures that can be taken to increase their longevity.
The 'ten agents of deterioration' are a conceptual framework developed by the Canadian Conservation Institute (CCI) used to categorise the major causes of change, loss or damage to cultural heritage objects. Also referred to as the 'agents of change', the framework was first developed in the late 1980s and early 1990s. The defined agents reflect and systematise the main chemical and physical deterioration pathways to which most physical material is subject. They are a major influence on the applied practice of conservation, restoration, and collection management, finding particular use in risk management for cultural heritage collections.