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Humidity buffering refers to the ability of materials to moderate changes in relative humidity by absorbing and desorbing water vapour from surrounding air. This is also referred to as moisture buffering.
The phenomenon has long been exploited for preserving items from damage that could be caused by either excessively moist or dry conditions.
Recently, there has been an interest in the field of building science and architecture in using humidity buffering as a passive indoor climate control, thus reducing the need for air conditioning and ventilation.
A cigar is a rolled bundle of dried and fermented tobacco leaves made to be smoked. They are produced in a wide variety of sizes and shapes. Since the 20th century, almost all cigars are made of three distinct components: the filler, the binder leaf which holds the filler together, and a wrapper leaf, which is often the best leaf used. Often there will be a cigar band printed with the cigar manufacturer's logo. Modern cigars often come with 2 bands, especially Cuban Cigar bands, showing Limited Edition bands displaying the year of production.
Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. The amount of water vapor needed to achieve saturation increases as the temperature increases. As the temperature of a parcel of air decreases it will eventually reach the saturation point without adding or losing water mass. The amount of water vapor contained within a parcel of air can vary significantly. For example, a parcel of air near saturation may contain 28 grams of water per cubic metre of air at 30 °C, but only 8 grams of water per cubic metre of air at 8 °C.
Relative humidity (RH) is the ratio of the partial pressure of water vapor to the equilibrium vapor pressure of water at a given temperature. Relative humidity depends on temperature and the pressure of the system of interest. The same amount of water vapor results in higher relative humidity in cool air than warm air. A related parameter is the dew point.
Silica gel is an amorphous and porous form of silicon dioxide (silica), consisting of an irregular tridimensional framework of alternating silicon and oxygen atoms with nanometer-scale voids and pores. The voids may contain water or some other liquids, or may be filled by gas or vacuum. In the last case, the material is properly called silica xerogel.
A hygrometer is an instrument used to measure the amount of water vapor in air, in soil, or in confined spaces. Humidity measurement instruments usually rely on measurements of some other quantities such as temperature, pressure, mass, a mechanical or electrical change in a substance as moisture is absorbed. By calibration and calculation, these measured quantities can lead to a measurement of humidity. Modern electronic devices use temperature of condensation, or changes in electrical capacitance or resistance to measure humidity differences. The first crude hygrometer was invented by the Italian Renaissance polymath Leonardo da Vinci in 1480 and a more modern version was created by Swiss polymath Johann Heinrich Lambert in 1755. Later, in the year 1783, Swiss physicist and Geologist Horace Bénédict de Saussure invented the first hygrometer using human hair to measure humidity.
A desiccant is a hygroscopic substance that is used to induce or sustain a state of dryness (desiccation) in its vicinity; it is the opposite of a humectant. Commonly encountered pre-packaged desiccants are solids that absorb water. Desiccants for specialized purposes may be in forms other than solid, and may work through other principles, such as chemical bonding of water molecules. They are commonly encountered in foods to retain crispness. Industrially, desiccants are widely used to control the level of water in gas streams.
A humidor is a humidity-controlled box or room used primarily for storing cigars, cigarettes, cannabis, or pipe tobacco. Either too much or too little humidity can be harmful to tobacco products; a humidor's primary function is to maintain a steady, desirable moisture level inside; secondarily it protects its contents from physical damage and deterioration from sunlight. For private use, small wooden boxes holding a few dozen or fewer cigars are common, while cigar shops may have walk-in humidors. Many humidors use hygrometers to monitor their humidity levels.
Psychrometrics, psychrometry, and hygrometry are names for the field of engineering concerned with the physical and thermodynamic properties of gas-vapor mixtures. The term comes from the Greek psuchron (ψυχρόν) meaning "cold" and metron (μέτρον) meaning "means of measurement".
An art exhibition is traditionally the space in which art objects meet an audience. The exhibit is universally understood to be for some temporary period unless, as is rarely true, it is stated to be a "permanent exhibition". In American English, they may be called "exhibit", "exposition" or "show". In UK English, they are always called "exhibitions" or "shows", and an individual item in the show is an "exhibit".
Glass disease, also referred to as sick glass or glass illness, is a degradation process of glass that can result in weeping, crizzling, spalling, cracking and fragmentation. Glass disease is caused by an inherent instability in the chemical composition of the original glass formula. Properties of a particular glass will vary with the type and proportions of silica, alkali and alkaline earth in its composition. Once damage has occurred it is irreversible, but decay processes can be slowed by climate control to regulate surrounding temperature, humidity, and air flow.
With respect to cultural heritage, 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. There are three broad categories of conservation science with respect to cultural heritage: 1) understanding the materials and techniques used by artists, 2) study of the causes of deterioration, and 3) improving methods/techniques and materials for examination and treatment. Conservation science includes aspects of chemistry, physics and biology, engineering, as well as art history and anthropology. Institutions such as the Getty Conservation Institute specialize in publishing and disseminating information relating to both tools used for and outcomes of conservation science research, as well as recent discoveries in the field.
Conservation and restoration of metals is the activity devoted to the protection and preservation of historical and archaeological objects made partly or entirely of metal. In it are included all activities aimed at preventing or slowing deterioration of items, as well as improving accessibility and readability of the objects of cultural heritage. Despite the fact that metals are generally considered as relatively permanent and stable materials, in contact with the environment they deteriorate gradually, some faster and some much slower. This applies especially to archaeological finds.
Object conservation is a term used to denote the conservation of works of art and three-dimensional artifacts. 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. This is called ‘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.
Collection maintenance is a form of collections care that consists of the day-to-day hands on care of collections and cultural heritage. The primary goal of collections maintenance 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 environments. Collections maintenance is closely linked to collections care and collections management. The professionals most influenced by collections maintenance include collection managers, registrars, and archivists.
The storage of cultural heritage objects typically falls to the responsibility of cultural heritage institutions, or individuals. The proper storage of these objects can help to ensure a longer lifespan for the object with minimal damage or degradation. With so many different types of artifacts, materials, and combinations of materials, keepers of these artifacts often have considerable knowledge of the best practices in storing these objects to preserve their original state.
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.
The conservation and restoration of bone, horn, and antler objects is the preservation of objects made from or containing these organic materials by preventive methods and treatments. Because these materials are both versatile and durable, they have been used throughout history for various tools and/or ornamentation including clothing, jewelry, and decorative art. These objects can be found in personal collections as well as cultural institutions and their collections.
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 panel paintings involves working with an object that is composed of two media: wood and paint. The process of conservation and restoration of paintings on canvas is different from that of panel paintings. In the United States, it is recommended that conservation practices follow the "Code of Ethics" set by the American Institute for Conservation of Historic and Artistic Works.
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.