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.
Although there are many different parts to a feather, all of the parts fall into two subsections of the feather. The two main sections of the feather are the shaft and the vane. [3]
The shaft is composed of the calamus and the rachis. The calamus can also be called the quill and is the hollow portion of the shaft that enters the skin follicle, while the rachis is the solid portion of the shaft where the barbs attach. [4]
The vane extends to either side of the rachis and is made up of interconnecting barbs, barbules, and "hooklets" known as hamuli. [4] [5] This is considered the most substantial portion of the feather.
Feathers found in museum collections are often part of composite objects, such as hats, fans, jewelry, and spiritual objects. [6] Their use in collection items that may be in need of conservation or restoration include purposes such as:
Many of the issues contained in this section can be eliminated or reduced through the proper care instructions listed in the below preventive and interventive sections.
While birds are alive, they are susceptible to several different pests including lice and mites. In particular, "chewing lice" like Mallophaga can infest a living bird, feed on and degrade its feathers. [3] Over 2500 species of mites are linked with birds, including those that live on feather plumage and within quill structures. [3] Despite the seeming threat, some current research suggests that at least some mites may be beneficial to living birds (and their feathers) by consuming bacteria and fungi thereby creating a symbiotic relationship. [7] Special sprays and soaps can kill these pests allowing the birds to regain feather growth and become healthy.
Because feathers are made largely of protein (keratin), they are a target for insects. Insects that like to eat protein based material will often feed on feathers causing serious damage including loss of feather material, burrowed or grazed surfaces, and frass. The most common threats come from the carpet beetle, hide beetles, larder beetles and clothing moths. [8]
Other organisms that can contribute to the deterioration of feathers include fungi. The high keratin content of feathers makes them susceptible to keratinophilic, or keratin loving, fungi. Some of these fungi, like Chrysosporium keratinophilum, can eventually completely consume and destroy feathers. Others, like Aspergillus and Penicillium , can cause black and green discoloration. [9]
There is also a risk presented by other animals, particularly rodents, who may damage items by eating them, using them for nesting, etc. In addition, these animals may bring other insects and mites with them or attract them after dying. [10]
Physical forces that contribute to deterioration include things like impact, shock, vibration, pressure and abrasion. [11] Feathers are very vulnerable to physical forces due to their fragile structure which can be easily bent and broken, and the structural color of some feathers can be affected by abrasion. [12]
Light can have a differential effect on the coloration of feathers depending on whether the color is caused by structural characteristics of the feather or by natural pigmentation due to melanin, carotenoids or psittacofulvins with coloration from pigmented feathers being more sensitive to light than those with structural coloration. [13] Feathers that have been artificially dyed by humans are even more highly sensitive to light. [12] In addition, the degree of fading can vary between bird species. [3] Most of the change in feather coloration occurs somewhat quickly upon initial exposure to light, and once this happens, the fading becomes somewhat stabilized. [14] Exposure to UV light can also cause feathers to become brittle [12]
Lower temperatures are generally preferred. [15] As temperatures get warmer, growth of mold/fungi can increase and the eating and breeding activities of pests can rise. [16] Temperatures that are too warm can also contribute to the expulsion of residual oils from the skins of taxidermy specimens which can in turn cause feather loss. [17] One study was shown to indicate that temperature can also contribute to color change in carotenoids with the most stable temperatures for color being below freezing. [13]
In addition to the temperature itself, the expansion and contraction cycles caused by fluctuations in temperature can also contribute to deterioration especially of composite objects that may include feathers as a component. Different materials can expand and contract at different rates causing components to work free of each other over time. [18]
Most of the danger from high relative humidity (RH) is related to its effect on the growth of mold/fungi and pest activity which is more likely when RH is higher than 65%. [19] High relative humidity can also increase chemical reactions resulting in things like the fading of artificial dyes. Similar to fluctuations in temperature, fluctuations in relative humidity can also put differential stress on composite objects where feathers are attached to other materials resulting in possible damage. [12] Dew point may also be an important concern as it relates to fluctuations in temperature below the dew point which can cause condensation to occur on surfaces. [19] Common sources of humidity include external air and weather, human respiration, broken pipes, mopping and flooded areas. [15]
Feathers can be naturally water repellant to some degree unless damaged. However, artificially dyed feathers can bleed or be stained if they come into contact with water. [12]
Feathers have a large surface area created by their structure which can easily capture particulates and "oily residues". [12]
Outdoor pollutants that can cause deterioration most commonly include sulphur dioxide, hydrogen sulfide, nitrogen oxide, nitrogen dioxide, and ozone which can react with objects or combine with other substances to produce sulphuric acid or nitric acid which in turn can cause damage to objects. [20] Gaseous pollutants can also come from indoor sources often in the form of organic acids, peroxides, formaldehydes and ozone, and can be generated by building materials, plastics, glues, paints, cleaning chemicals or office equipment. [20]
Particulate pollutants include substances such as dust, soot, smoke, pollen, and soil which can be abrasive to feathers, attract pests and chemically react with moisture. [15] Allowing particulates to accumulate on feathers also creates the need for cleaning which can put fragile feathers at risk for physical damage. [15] In addition, particulates can cause the relative humidity around the feather to rise. This rise in humidity and the resulting addition of moisture can accelerate the deterioration of the feather. [2]
Humans use feathers in many different ways. Certain species of bird feathers are highly sought after or are rare or valuable. Because of this, some feathers are at risk for theft. One recent example was an incident in the UK in 2009 when 299 bird specimens, some originally collected by Alfred Russel Wallace, were stolen from the Natural History Museum at Tring with the intent to sell the feathers for fly tying. [21]
Preventive conservation seeks to preemptively assess how collection objects may be affected by agents of deterioration, and how to best combat or slow down their influence. Accurate record keeping is an important tool for preventive conservation. [22] Having detailed records to consult and being able to repeat the same method of testing where applicable will most accurately depict any changes happening to the object.
The proper care and handling of feathers is essential for the survival of the object.
Alkaline storage or display construction materials are not favorable to feathers, as they will cause the chemical deterioration of items made from animal products. Better suited for feather storage and display are acid-free, pH-neutral, or un-buffered materials, such as boxes or tissues. [23]
The complex structures of organic materials in general make them vulnerable to deterioration from extremes and variations in RH and temperature. [24] The temperature and RH can be monitored with a climate control system or managed on a smaller scale using silica gel packets in storage or display areas. Cotton and acid-free tissue are humidity-buffering materials that may be used in storage solutions. [25]
The organic makeup of feathers make them a food source for mold, insects, rodents and other museum pests. [24] Implementing an Integrated Pest Management Program can help identify any current or potential pest issues. If active pests are suspected, featherwork can be stored within two layers of well-sealed polyethylene bags, labeled with the date. [26]
Exposure to light can cause "color shift and/or embrittlement in organic materials". [24] As structural color relies on the physical structure of the feather, and not pigmentation, these feathers are less likely to be adversely affected by light exposure in regards to their coloring. Feathers colored by pigmentation are most susceptible to fading or discoloration while on display, and so require more stringent lighting provisions. [27] UV filtration in storage and display areas is one way to manage light exposure. [28]
Feathers come in all shapes and sizes, and can be very delicate. This makes them susceptible to crushing or distortion if improperly stored with and/or near a heavier object. [24]
As feathers are made of fibrous materials, they can easily absorb airborne pollutants. The structure of feathers, with their tiny barbed branches, make dust an issue for feathers. Dust covers can be used to prevent dust from building up on the object while in storage or on display. [25]
Feathers are flammable, especially if dry and/or brittle. For fire safety and prevention, eliminating the threat of fire hazards is often the preferred method of control. [29]
When handling feathers, wearing nitrile gloves will protect feathers from skin oils, as well as protect the skin from any harmful pollutants that may be on the feather. [28] Protection for eyes and lungs may also be needed.
Necessary in storage and display of featherwork is a proper support system. Materials that may function well in this regard are Tyvek and Ethafoam, which can be carved and shaped to fit unique objects. [28]
Due to the particularly high risk of deterioration from pests, many feathered objects and specimens have been treated historically with a variety of substances intended as a pesticide. These substances, including hazardous chemicals such as mercuric chloride, benzene, arsenic, strychnine and even dichlorodiphenyltrichloroethane (DDT) among others, were used in various mixtures and applied in both liquid and powdered form to objects in collections. [30]
Residues from past applications of hazardous insecticides may be present even if not visible; therefore, the use of gloves, respirators, eye protection and other protective clothing can be used to avoid contact. [12] During handling, feathers can be placed on tissue or a sheet of Tyvek to prevent the spread of pesticide residue onto the surrounding environment or workspace, and the use of a HEPA filtered vacuum can prevent the propagation of pesticide residue particles into the air. [28]
If any pesticide residues are discovered, certain legal obligations may exist, such as NAGPRA in the US, that require the institution to notify the recipients of the objects about the presence of the hazardous substances.
Removing debris and organic matter from feathers is a key step in the conservation process. Here are several of the ways that feathers are typically cleaned by conservators:
Using a small HEPA-filtered vacuum allows conservators to clean off dust and other particulate debris that is not embedded onto the feather. This method cannot be done by conservators when dealing with fragile feathers due to the likelihood of damage. [31] Flat sable paintbrushes can also be used to remove light dust or dirt from feathered objects. Additionally, microfiber cloths are highly effective at removing and trapping dust. For contour feathers, latex-free cosmetic sponges can also be used as a dry-cleaning tool. [26]
Certain gentle soaps solvents are typically used to clean feathers and are mainly used for feathers that have not been dyed or painted in order to prevent color bleeding. One such solvent, isopropyl alcohol, is usually diluted to make it less caustic to the specimen. Isopropyl alcohol is also a fast-drying solution that will not cause the feathers to remain wet for an extended period of time. Diluting ethanol with water is an effective method for cleaning natural feathers that are free from dye. Gentle soaps and solvents will often also be used on living specimens when approved by a vet or zoologist. [31]
A living specimen can sometimes lose some of their vital flight feathers and there are ways of repairing them to restore flight to the bird. Feathers from another source are placed in the hollow portion of the quill and securing them with small splints. In the aviary world this process is called imping. A procedure such as this allows a bird to resume flight until the old quill falls out and a new feather takes its place during molting. [32]
Mounted birds and feathers are repaired with several simple methods. Feathers that are tattered or messy can be moved back into shape with the use of mist, warm cotton compresses, or light steam. [33] In the case of feathers that are falling out of a mount or broken in two, the pieces are reattached with small amounts of adhesive, or adhered to a splint to restore the feather's structure. [34] Extreme care is always used to not get the adhesive stuck onto the barbs. A wheat starch paste adhesive is utilized in some cases to reattach feathers to skin or to each other. [34]
There are many different sources both online and in person to learn more about feather conservation. The AIC Wiki, [35] as well as the AIC Wiki for Feathers, are jumping points into conservation topics, including the care of feathers. Many museums and conservation organizations are also providing classes in the conservation of feathers.
Demouthe, Jean Frances. Natural materials sources, properties, and uses. Amsterdam; Boston; London: Elsevier/Architectural Press, 2006.
Pearlstein, Ellen J. The Conservation of Featherwork from Central and South America / Edited by Ellen Pearlstein. 2017. Print.
Wright, Margot M., and Conservators of Ethnographic Artefacts. The Conservation of Fur, Feather and Skin: Seminar Organised by the Conservators of Ethnographic Artefacts at the Museum of London on 11 December 2000 / Edited by Margot M. Wright. London: Archetype, 2002. Print. CEA Ser. ; No. 3.
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 ivory objects is the process of maintaining and preserving objects that are ivory or include ivory material. Conservation and restoration are aimed at preserving the ivory material and physical form along with the objects condition and treatment documentation. Activities dedicated to the preservation of ivory objects include preventing agents of deterioration that specifically connect with ivory as a material, preventative conservation, and treatment of ivory objects. Conservators, curators, collections managers, and other museum personnel are in charge of taking the necessary measurements to ensure that ivory objects are well maintained and will make the decision for any conservation and restoration of the objects.
Conservation and restoration of movable cultural property is a term used to denote the conservation of movable cultural property items in libraries, archives, museums and private collections. Conservation encompasses all the actions taken toward the long-term preservation of cultural heritage. Activities include examination, documentation, treatment, and preventive care, which is supported by research and education. Object conservation is specifically the actions taken to preserve and restore cultural objects. The objects span a wide range of materials from a variety of cultures, time periods, and functions. Object conservation can be applied to both art objects and artifacts. Conservation practice aims to prevent damage from occurring, a process known as 'preventive conservation'. The purpose of preventive conservation is to maintain, and where possible enhance, the condition of an object, as well as managing deterioration risks, such as handling and environmental conditions. Historically, object conservation was focused on the category of fine arts but now many different types of objects are conserved. Each type of object material, typically denoted by organic or inorganic then the specific medium, requires a specialized professional conservator and often requires collaborative work between museum staff, scientists, and conservators.
Conservation and restoration of objects made of glass is one aspect of conservation and restoration of cultural heritage. The nature and varying composition of the material, and the variety of types of object made from it, demand certain specialized techniques. The conservator needs to be aware of "agents of deterioration" presenting particular risk to glass objects, and how to prevent or counteract their effects. Relevant education and training is available in certain countries through museums, conservation institutes and universities.
Collection maintenance is an area of collections management that consists of the day-to-day hands on care of collections and cultural heritage. The primary goal of collections maintenance or preventive conservation is to prevent further decay of cultural heritage by ensuring proper storage and upkeep including performing regular housekeeping of the spaces and objects and monitoring and controlling storage and gallery environments. Collections maintenance is part of the risk management field of collections management. The professionals most involved with collections maintenance include collection managers, registrars, and archivists, depending on the size and scope of the institution. Collections maintenance takes place in two primary areas of the museum: storage areas and display areas.
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.
Integrated pest management in museums, libraries, archives and private collections is the practice of monitoring and managing pest and environmental information with pest control methods to prevent pest damage to collections and cultural property. Preserving cultural property is the ultimate goal for these institutions. The pests come in many different forms: insects, mites, rodents, bats, birds, and fungi and the two most common types are insects and fungi. It is widely recommended that every museum have some form of pest control in place and monitoring system to protect their collection and that museums review their storage and museum facilities to determine how to best control and prevent pest infestations while utilizing an Integrated Pest Management plan.
Conservation and restoration of objects made from plastics is work dedicated to the conservation of objects of historical and personal value made from plastics. When applied to cultural heritage, this activity is generally undertaken by a conservator-restorer.
The conservation and restoration of clocks refers to the care given to the physical and functional aspects of time measuring devices featuring "moving hands on a dial face" exclusive of watches. Care for clocks constitutes regulating the external environment, cleaning, winding, lubrication, pest-management, and repairing or replacing mechanical and aesthetic components to preserve or achieve the desired state as specified by the owner. Clocks are typically composed of multiple types of materials such as wood, metal, paint, plastic, etc., which have unique behaviors and environmental interactions, making treatment options complex. The materials used and the complexity of clockwork warrant having a Horological Conservator complete the work.
The conservation and restoration of painting frames is the process through which picture frames are preserved. Frame conservation and restoration includes general cleaning of the frame, as well as in depth processes such as replacing damaged ornamentation, gilding, and toning.
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.
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 of taxidermy is the ongoing maintenance and preservation of zoological specimens that have been mounted or stuffed for display and study. Taxidermy specimens contain a variety of organic materials, such as fur, bone, feathers, skin, and wood, as well as inorganic materials, such as burlap, glass, and foam. Due to their composite nature, taxidermy specimens require special care and conservation treatments for the different materials.
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 wooden artifacts refers to the preservation of art and artifacts made of wood. Conservation and restoration in regards to cultural heritage is completed by a conservator-restorer.
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 conservation and restoration of quilts refers to the processes involved in maintaining the integrity of quilts and/or restoring them to an acceptable standard so that they may be preserved for future generations. Quilts have been produced for centuries, as utilitarian blankets, decorations, family heirlooms, and now treasured museum collections objects. Quilts are three-layered textile pieces with a decorated top, a back, and a filler in the middle. The composite nature of these objects creates an interesting challenge for their conservation, as the separate layers can be made of different textile materials, multiple colors, and therefore, varying degrees of wear, tear, and damage.
The conservation and restoration of historic firearms is preventative care, damage repair, stabilization, replacement of missing components, and potentially the return of the firearm to firing capabilities. It requires an understanding of the different types of historic firearms and knowledge in the care and treatment of organic and inorganic materials, as firearms are composed of many types of materials, from wood to metal, that are fitted together.
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.