LIS 226 Preservation of Information Resources.pptx

LIS 226 - Preservation of Information Resources Unit 1: Definitions and Review of Practices of Preservation and Conservation  “Preservation” is defined as “the act of preserving, or keeping in safety or security from harm, injury, decay, or destruction.” “Conservation” has retaine...

LIS 226 - Preservation of Information Resources Unit 1: Definitions and Review of Practices of Preservation and Conservation  “Preservation” is defined as “the act of preserving, or keeping in safety or security from harm, injury, decay, or destruction.” “Conservation” has retained the second meaning, with emphasis on the physical treatment of specific items or collections. It includes simple preventive steps as well as major procedures that may require many weeks of work. The words are still often used interchangeably, so we will have to be patient and see how the usage evolves. “Preservation” refers to steps that address the Preservation ◼Includes all the managerial and financial considerations, including ▪ Storage and accommodation provisions ▪ Staffing levels ▪ Policies ▪ Techniques ▪ Methods ▪ involved in preserving library and archival material and the information contained in them. Conservation ◼Specific practices taken to slow deterioration and prolong the life of an object by directly intervening in its physical or chemical make- up. ▪ Examples ▪ repairing damaged bindings ▪ deacidifying paper  Preservation—The protection of cultural property through activities that minimize chemical and physical deterioration and damage and that prevent loss of informational content. The primary goal of preservation is to prolong the existence of cultural property. Conservation—The profession devoted to the preservation of cultural property for the future. Conservation activities include examination, documentation, treatment, and preventive care, supported by research and education. Restoration—Treatment procedures intended to return cultural property to a known or assumed state, often through the addition of non-original material. Why preserve The type of library and how it is used reflect the preservation needs of its collections. The preservation requirements of a local public lending library are obviously different from those of a national library. However, both are obliged to maintain and keep accessible their collections, whether for a few years or indefinitely. Economically, libraries cannot afford to let their holdings wear out prematurely. Replacing library material, even when possible, is expensive. Preservation makes good economic sense. Why preserve ◼It cannot be easily predicted what will be of interest to researchers in the future. ◼Preserving current collections is the best way to serve future users. ◼Responsible and professional library staff should be committed to caring for and preserving the material with which they work. Preserving and Protecting Documentary materials means materials upon which information is recorded and includes, but is not limited to, written or printed materials, photographs, tapes, videotapes, negatives, films, and interview files. Archives preserve and protect historical documents, paper, photographs, manuscripts, AV materials, Electronic formats and other significant materials. These materials provide insight into the past and serve as invaluable research, education, and cultural understanding resources. Without proper preservation and conservation measures, these materials can deteriorate, become inaccessible, or even be lost forever.  Preservation focuses on preventing damage and slowing the natural decay of archival materials. It encompasses various activities and strategies that address environmental factors, handling practices, and storage conditions. Controlling temperature and humidity levels in archival spaces is crucial to ensure the stability and longevity of the materials. High temperatures and fluctuations in humidity can accelerate chemical reactions and physical degradation. Therefore, archives must maintain stable and controlled environments, ideally with a temperature around 20°C (68°F) and relative humidity between 30% and 50%. Conservation focuses on repairing, stabilizing, and restoring damaged or deteriorated materials. treatments can range from minor repairs, such as mending tears or reinforcing loose bindings, to complex processes like deacidification or digitization. Agents of Deterioration 1. Physical, mechanical, biological, chemical agents 2. Damage from Environment Factors of Deterioration 1. Physical Deterioration caused by physical factors such as wear and tear, use, handling, movement, etc. 2. Biological (also Degradation, Damage) Deterioration caused by biological factors such as mold, insects, rodents, etc. 3. Chemical Deterioration resulting from reaction between primary support and/or media and other chemical species such as atmospheric pollutants, residues from manufacture and poor quality materials.  Ten Agents of Deterioration by the Canadian Conservation Institute (CCI) 1. Physical Force: Includes impacts, vibrations, and pressure that can break, crack, or deform objects. This can happen during handling, transportation, or due to environmental factors like earthquakes. 2. Fire: Causes immediate and often irreversible damage through burning, charring, and smoke. It can destroy entire collections and structures. 3. Water: Leads to swelling, warping, staining, and mold growth. Prolonged exposure can cause materials to rot or disintegrate. 4. Pests: Insects, rodents, and other pests can chew through materials, leaving holes and weakening structures. They can also leave behind waste that causes further damage. 5. Neglect: Lack of proper care and maintenance can lead to gradual deterioration. Dust, dirt, and environmental pollutants can accumulate, causing long-term damage.  Agents of Deterioration 6. Theft and Vandalism: Loss or intentional damage to objects. This can include graffiti, scratches, or complete destruction of items. 7. Incorrect Temperature: Extreme temperatures can cause materials to expand and contract, leading to cracking, warping, or other forms of structural damage. 8. Incorrect Humidity: High humidity can promote mold growth and corrosion, while low humidity can cause materials to become brittle and crack. 9. Chemical Deterioration: Exposure to harmful chemicals, pollutants, or acidic environments can cause materials to break down at a molecular level, leading to discoloration, weakening, or complete disintegration. Exposure to harmful chemicals, pollutants, or acidic environments can cause materials to break down at a molecular level, leading to discoloration, weakening, or complete disintegration. 10. Light and Ultraviolet Light: Prolonged exposure to light, especially UV light, can cause fading, discoloration, and weakening of materials, particularly organic ones like textiles and paper. Environmental (climatic Factors) factors like light, heat, humidity and moisture, dust and dirt, water. Light is energy and energy is required for chemical reactions to take place. All wavelengths of light – visible, infrared, and ultraviolet (UV) – promote the chemical decomposition of organic materials through oxidation. Some Facts about Light Natural Light We are mainly concerned with Whether natural light or three types of rays found in natural artificial light paper gets light: ultraviolet (UV), visible, and deteriorated when it is infrared (IR). exposed to light. Ultraviolet Light Sunlight is rich in ultraviolet rays, Especially sun light, has which are not visible to the human a serious damaging effect on eye. written or printed paper materials. Ultraviolet Light This is the part of the light spectrum that is most damaging to paper, textiles, and leather (including book bindings), many plastics, and all kinds of photographic processes. Fading, color changes, brittleness, cracking, and delaminating are all results of the accelerated aging that is caused by UV light. Visible Light This is the part of the light spectrum that we actually perceive as light. Although not in the UV range, high levels of visible light still cause deterioration, but at a much slower rate than UV light Infrared Light Infrared light is not visible to us but is felt as radiant heat. Sunlight coming through skylights and windows generates significant amounts of heat; Artificial Light Artificial light is much less bright than sun light, it can still cause fading and deterioration. There are a few types in common use for indoor lighting. Fluorescent Lamps After natural light, the most common source of UV radiation is fluorescent lighting. Fluorescent Lamps After natural light, the most common source of UV radiation is fluorescent lighting. Incandescent (Tungsten) Lamps The normal light bulbs found in homes are tungsten lamps, also called incandescent lamps. Temperature and Humidity Temperature is a measure of heat energy, and damage may occur when the temperature is either too high or too low. Temperature directly affects relative humidity (RH) , and consequently a fluctuating temperature leads to a fluctuating Example of deterioration from relative humidity. exposure to incorrect temperature High humidity can promote mold and physical forces: the wax nose of this mammal taxidermy mount is growth and corrosion, while low flattened on one side because of humidity can cause materials to incorrect temperature (too high) become brittle and crack. combined with physical forces (incorrectly stored resting on the end of the nose). Hygrometer s Hygrometers measure humidity. Very small instruments which is only 2" (5 cm) long. It has a dial for temperature and one for RH and also a row of squares along the bottom that show RH by color change from pink to blue (fig. 1 4) The effects of temperature Heat coupled with low relative humidity will eventually lead to desiccation and embrittlement of certain materials – leather, parchment/vellum, paper, adhesives, the adhesive binders on audio and video cassettes, etc. Heat together with high relative humidity encourages mould growth and creates an environment conducive to pests and insects. Cold (less than  °C / °F) together with high relative humidity and poor air circulation will lead to dampness and eventually mould growth. Relative humidity (RH) The effects of relative humidity ◼A low RH (less than 40%) minimizes chemical change but can cause materials to shrink, stiffen, crack, and become brittle. (Adcock, Varlamoff, & Kremp, 1998) Atmospheric and particulate pollution ◼Air pollution is to a large extent associated with towns and industry and is another cause of damage to paper and other organic materials. ◼Air pollutants vary greatly in nature, from gases to particulates such as dirt and dust. (Adcock, Varlamoff, & Kremp, 1998) Gaseous pollutants ◼Gaseous pollution is caused overwhelmingly by the burning of fuels. ◼Pollutants such as sulphur dioxide, hydrogen sulphide, and nitrogen dioxide combine with moisture in the air to form acids that attack and damage library material. (Adcock, Varlamoff, & Kremp, 1998) Gaseous pollutants ◼Ozone is a powerful oxidant which severely damages all organic materials. ▪ It is a product of the combination of sunlight and nitrogen dioxide from automobile exhaust; ▪ it may also be produced by electrostatic filtering systems used in some air conditioners, as well as by electrostatic photocopy machines. (Adcock, Varlamoff, & Kremp, 1998) Gaseous pollutants ◼Smoking, cooking, and off-gassing from unstable materials (cellulose nitrate film, paint finishes, fire- retardant coatings, and adhesives) may also produce harmful gaseous pollutants. (Adcock, Varlamoff, & Kremp, 1998) Gaseous pollutants ◼Wood, particularly oak, birch and beech, emit acetic and other acids, and vulcanized rubber releases volatile sulphides that are especially damaging to photographs. (Adcock, Varlamoff, & Kremp, 1998)  Particulate pollutants ◼Dust and dirt that have absorbed gaseous pollutants from the air become sites for harmful chemical reactions when they settle on library material. ◼Particulate pollutants can also aid mould growth. (Adcock, Varlamoff, & Kremp, 1998)  Particulate pollutants Dust ◼is commonly a mixture of fragments of human skin, minute particles of mineral or plant material, textile fibres, industrial smoke, grease from fingerprints, and other organic and inorganic materials. (Adcock, Varlamoff, & Kremp, 1998)  Particulate pollutants Salts ◼There are often salts such as sodium chloride (carried in from sea spray or on skin fragments) and sharp gritty silica crystals. ▪ In this chemical mixture are the spores of countless moulds, fungi, and micro- organisms which live on the organic material in the dust (fingerprints, for example, serve as good culture media). Particulate pollutants Dirt ◼Much of the dirt is hygroscopic (water attracting), ▪ and this tendency can encourage the growth of moulds, ▪ as well as increase the corrosiveness of salts, hydrolysis, and the release of acids. Particulate pollutants Soot ◼a black substance formed by combustion or separated from fuel during combustion, rising in fine particles, and adhering to the sides of the chimney or pipe conveying the smoke ◼the fine powder consisting chiefly of carbon that colors smoke. ◼ (https://www.merriam-webster.com/dictionary/soot) Mould A surface growth of fungus which may have varying color, shape, and configuration. It generally proliferates in damp conditions (60% relative humidity or greater) where there is little air circulation. Active mold smears when touched whereas inactive mold is powdery and dry. Damage caused by mold includes staining and loss of strength. Other types of damage commonly mistaken for Mold ▪ Dirt ▪ Foxing ▪ Efflorescence  Dirt / Grime Any undesirable foreign matter which has accumulated on the surface. May be embedded of superficial. Grime is dirt of a greasy nature. (Also dust, soiling, accretion).  Foxing Foxing is characterized by reddish-brown spots that appear on paper. Random, rust- coloured spots on paper. Efflorescence The formation of a powdery deposit on the surface of brickwork, rock, or other material as a result of loss of moisture on exposure to air: ◼ appears when fats and salts in leather or heavily starched cloth crystalize and form a precipitate. ◼ has a white, crystalline Attending to an infestation ◼Mould can be checked to see whether it is active or inactive. ▪ Generally, active mould is damp, slimy, and smears if touched. ▪ Inactive mould is dry and powdery and can be brushed off with a soft brush. Attending to an infestation ◼If mould is discovered in large portions of a collection, isolate the area immediately and do not attempt to clean up without first consulting a mycologist to determine if toxic moulds are present. ◼Certain moulds commonly found in libraries can pose serious health risks, causing headaches, nausea, eye and skin irritation, and respiratory problems. Attending to an infestation A conservator may have to be employed or at least consulted on the treatment of infested items and on the return of the affected area to a suitable condition for housing material. Attending to an infestation ◼If only a few items are affected, place them in a dry paper-based box until treatment. ◼If possible, include a desiccant, such as conditioned silica gel packets. ◼This enclosure will prevent spores from circulating, but will not encourage the growth potentially created by the tightly sealed microclimate of a plastic bag. Treating an infested area ◼ If the RH is above 55%, it must be lowered before the collection is returned to the area. Adjusting the HVAC (Heating, Ventilating, and Air Conditioning) system or adding a portable dehumidifier may be all that is necessary. Also check for leaks or water condensation on outside walls. Inspect the heat-exchange coils in the heating/air- conditioning system, a notorious breeding ground for fungi, and clean them with a household disinfectant. Treating an infested area ◼ Vacuum clean the shelves and floor with an HEPA (High- Efficiency Particulate Air) filter vacuum cleaner, then clean them with a household disinfectant. ▪ Before returning the cleaned material to the area, monitor the RH for several weeks to make certain it does not exceed 55%. ◼ After the items are returned, check daily for new mould HEPA (high-efficiency outbreaks. particulate air) filter Water Water occurs in all the normal state of matter- solid, liquid and gas. It acts as a physical agent of deterioration by causing hygroscopic materials to undergo dimensional changes. Water, which is harmful for the library collection may come from sources like natural calamities, human negligence, from leaking roofs, defective plumbing and through open windows at the time of raining. Excessive water brings about biological attack on paper, which is usually manifested as the growth of fungus or mildew. The effects of water are stained paper, rotted leather, smeared ink, weaken adhesive, sustained fungi etc. Water also does injury to the steel furniture due to rusting. BIOLOGICAL FACTORS The deterioration caused by biological agents such as micro-organisms, insects and rodents is generally known as bio-deterioration. These biological agents can be subdivided into : I. Micro-organisms: 1) Fungus or moulds, 2) bacteria etc. II. Insects III. Rodents Insects and pests ◼Insects which most commonly cause damage in libraries and archives throughout the world are : ▪ Cockroaches ▪ Silverfish ▪ Booklice ▪ Beetles ▪ Termites Silverfish, Lepisma saccharina The main source of these insects are food materials like starch, glue and gelatin which are used in paper as sizing materials. Silverfish do not have wings and are silvery or pearl gray in color and about 8 to 10 mm. in length. They eat the surface of the paper and also eat gum from postage stamps, envelopes etc. They grow holes in paper, prints, photographs, catalogue cards and cardboard boxes.  Booklice Dark dusty areas filled with unused books, dampness and warmth are essential requirements for the growth of booklice. They are gray or white in color. They injure the bindings of books by eating paste and glue and also eat the fungus formed in between the edges of inner cover of the books. May be found under wallpaper, in furniture, along the sides of windows or on window sills around potted plants. Termites or White Ants Wet or damp conditions are most suitable places for termites. They eat wood and paper and can attack any type of material containing cellulose. If once they start destroying the books they can do irreparable damage in no time. They leave mud encrustation on the attacked materials. Book worms or Book beetles Bookworms affect very much books and manuscripts. As the name itself suggests they feed on paper and damage the paper extensively. In libraries the bookworms lay their eggs on the edges of the books and on the surface of the bookbinding. They make tunnels in the pages and Pests ◼They will destroy books in order to obtain paper for their nests. ◼They can cause fires by gnawing through electrical insulation. ◼They will pare their teeth on library furniture and fittings. ◼Their droppings are corrosive and can leave permanent stains. Rodents Rodents include mice, rats, squirrels and many other species. Mice and rats are mainly found in libraries and they find their way into buildings through dry drains and openings in doors and windows. In libraries they eat and destroy materials made up of paper, cloth, leather, glue, etc. These animals are very swift CHEMICAL FACTORS In the manufacturing of paper sometimes fibers are used with low cellulose contents and some chemical compounds like alum, rosin etc. are used for sizing of paper which cause acidic effect and facilitate chemical deterioration of the paper with the passage of time. Because of the absorption of the chemicals by the moisture absorbed by the paper, the library materials get affected. The notable deleterious substances for the library materials are sulphur dioxides, oxides of nitrogen and ozone. Sulphur dioxide is a hazard to cellulose materials like paper and cloth. The most familiar effect in libraries is the brown and brittle edges of books caused by sulphur dioxide.  HUMAN FACTORS Apart from physical and chemical factors, a serious cause of deterioration often is the casual attitude of the library staff as well as the users of the library towards books as physical objects. Librarians in charge of the documentary heritage are directly responsible for the overall conservation and preservation of their collections. But they are not always aware how to handle, store and use collections carefully to minimize damage and help preservation. Improper storage, faulty repairment, rough handling, deliberate abuse, folding the fore-edges of Preventive Conservation I. ENVIRONMENTAL MONITORING AND CONTROL Control of environmental factors partially begins from selection of site, the planning and the construction of the library building and also the soil on which it will be constructed because these elements have greater impact over the environmental control inside the library building. Sunlight should be prevented from falling directly on papers because the sun is a great emitter of ultraviolet rays. The windows must be provided with colored curtains, which will prevent falling of direct light as well as absorb ultraviolet rays. Lemon yellow or green colored glass panes should be fitted in window panes as these are more effective in blocking ultraviolet rays.  As high humidity and high temperature are more hazardous for library materials it is advisable to maintain ideal room temperature (200-250c) and relative humidity of (RH45- 55%) for preservation of documents. Air conditioning of the stack area round the clock is an ideal example of maintaining optimum temperature & humidity for the storage of documents. But it is practically not possible for all the libraries to afford for air conditioning for 24 hours. High humidity could also be minimized by the use of de- hydrating agents like silica gel. The requisite quantities of silica gel may be spread in dishes and kept in different places in the room. After the use for 3-4 hours the silica gel may get saturated and may need replacement with fresh gels, while the saturated gel can be reactivated for further use after heating it in open pans.  During the summer months when the temperature is high the windows should be kept closed. If the windows are to be kept open wet curtain should be used. High speed air circulators also be used for free air circulation. Floors can be cleaned by wet dusters. As accumulation of dust and dirt accelerate the physical damage of books, a cleaning schedule should be made considering the sequence of operations following daily and weekly routines. The best way is to use a vacuum cleaner because it sucks the dust and can not resettle on the surfaces. II. PREVENTIVE MEASURES FOR BIOLOGICAL FACTORS Since stagnant air, dampness, dark and dingy places in a library facilitate the growth of biological pests, good housekeeping and maintenance of optimum storage condition is necessary to control the propagation of the insects. It is preferable to avoid contact of book racks with walls (at least 15 cm away from the walls) to eliminate dampness. Attending to cracks, crevices and loose joints in floors and walls eliminate the possibility of insect hiding in these places. Presence of edibles inside the library should not be allowed. A simple practice is to keep naphthalene bricks on the shelves as it repels the insects from coming to the book racks. Dry neem leaves, neem seed powder and camphor tablets tied in muslin bags should be kept inside the racks for keeping the pests away. The foundation of all the new library buildings should be given anti-insect treatment. III. PREVENTIVE MEASURES FOR CHEMICAL FACTORS One of the best ways of controlling atmospheric pollutants is filtering of the air intake in to storage areas, which can be attained by air conditioning system operating for 24 hours throughout the year. Simple measures like wrapping the books and manuscripts in cloth or placing them in book containers reduces the effects of pollution to a great extent. The books kept inside cupboards are better protected than those which are kept outside. Documents kept inside folders are safer than those which are kept in the open. Proper care should be taken to save books and documents from dust. It is preferable to use vacuum cleaner and fine brushes for dusting of shelves and books. No chemical formulations should be directly applied on to the book covers, since these may have an adverse effect on the books as well as users of the books and staff of the library. Wooden storage should be avoided as it gives off volatile acidic vapors. If it is to be used it must be covered with coats of acrylic emulsion paint. Besides, acid free paper, board and good quality materials should be used for repair and restoration of documents. PREVENTIVE MESURES FOR HUMAN FACTORS There are certain do’s and don’ts which the library staff and the users should follow to increase the longevity of the library resources. 1. Important books and manuscripts should kept in specially prepared containers. 2. For carrying a large number of books trolleys should be used. Utmost care should be taken while transporting rare, valuable and delicate books. 3. Care should be taken while photocopying the books as at that time considerable stress is imposed on the material and the bindings suffer most and also the spine damages. 4. Use bookends to support books when shelves are not full. Books should not be shelved too tightly or too loosely. PREVENTIVE MESURES FOR HUMAN FACTORS 5. It must be always ensured while opening the books, pages are not torn or covers are not damaged. To turn a page lift the top corner and lightly slip the finger tips down the fore-edge supporting the page. 6. Pages should never be folded otherwise creases will be formed and they may be torn at the folds. Corner of pages should not be folded to mark pages. 7. Avoid licking of fingers as an aid to turn pages. 8. Underlining must be avoided. 9. Leaning on an open book should be avoided since this can damage the spine and binding. 10. Never allow a book to stand on its fore edge. 11. When a book is displayed open, never use metal clips or pins to hold book pages open.  Environmental Monitoring Equipment Hygrothermograph Hygro (from the Greek hugros, meaning "moisture/humidity") + thermo (a Greek root meaning "heat") + graph (from the Greek root grapho, meaning "write") A hygrothermograph is an instrument that measures and records both temperature and relative humidity, simultaneously, onto a single chart. The temperature is recorded by the upper pen, which is controlled by the movement of a bimetallic strip. The humidity-sensing element is comprised of small bundles of human hair. The hair lengthens or shortens depending on the humidity of the surrounding air. This motion is transferred to the lower pen by means of a lever mechanism. The chart is installed on a drum which is rotated by a battery-powered clockwork mechanism. The mechanism has three output speeds, so that one-day, seven-day, and 31-day charts can all be accommodated on the one instrument. Aspirating Psychrometer An aspirating psychrometer is an instrument that measures the relative humidity in the atmosphere using two thermometers: one dry and one wet. Each inside a double tube for minimizing radiative heating both by the direct sun and longwave radiation exchange between thermometer and surrounding tube. The difference between the two temperatures provides a basis to determine how much moisture is in the air. Data Loggers Data loggers are extensively used in environmental monitoring applications to measure and record parameters such as temperature, humidity, air quality, and water quality. Data loggers monitor relative humidity and temperature digitally. They help scientists and researchers analyze environmental trends, study climate change, and monitor pollution levels. Humidity Indicator Cards (HIC) Humidity indicator cards use a moisture sensitive salt (cobalt chloride) to monitor the relative humidity levels. Humidity indicator cards have 10 small patches of fabric which change color from pink to blue depending on the humidity levels. Check the color of the spots on the card. Each spot corresponds to a specific humidity level. A blue dot indicates safe humidity levels. A shift to pink suggests increased humidity. Evaluate the HIC colors periodically to monitor changes. Integrated Pest Management (IPM) Integrated pest management (IPM), also known as integrated pest control (IPC) is a broad- based approach that integrates both chemical and non-chemical practices for economic control of pests. Preventing insect and pest infestations It is now accepted that an integrated pest management (IPM) approach should form part of every preservation programme. Preventing Insect and Pest Infestations IPM involves: ◼ understanding the biology and life cycles of insects and pests, which helps to know when and where they are likely to breed, what they are likely to eat, where they are likely to live ◼ eliminating or containing all sources of likely infestation – ideally food and drink should not be consumed on the premises; flowers and plants should not be allowed in the building ◼ maintaining an environment not conducive to pests and insects, which is clean, cool, dry, and well-ventilated. Preventing Insect and Pest Infestations IPM involves: ◼ preventing pests and insects from entering the building – making sure doors close properly, installing mesh screens for windows and doors, etc. ◼ using appropriate exterior lighting, such as sodium vapor, which is less attractive to insects. ◼ implementing a cleaning and hygiene program – ▪ rubbish should be safely and properly disposed of; ▪ attics and basements regularly checked and cleaned. Preventing Insect and Pest Infestations IPM involves: ◼monitoring the building regularly for the presence of insects and pests ◼ensuring all staff, from cleaners to librarians, are vigilant and report any signs of fresh damage and activity ◼checking all material which is to be accessioned before it enters the library Preventing Insect and Pest Infestations ◼Library buildings should be designed as far as possible to meet preservation requirements.  What to Do – Low Cost Solutions Implement an environmental monitoring program to assess the current environment; determine whether you have any cooler, dryer areas that could be used for storing photographic materials and other media that require a lower relative humidity and temperature.  Avoid basements and attics for storage.  Add weather stripping around doors and windows to stop air leaks in wet and dry season.  Install an air-conditioning unit if summertime temperatures exceed 25°C in the archival storage area.  Prevent water damage by good roof maintenance and prompt action in repairing leaky pipes.  Ensure proper drainage around the building.  Insulate the building to buffer exterior temperature change.  Use humidifiers and dehumidifiers as required. Stack Management Environmental Control Standards Guidelines for Humidity and Temperature in Canadian Archives ranks archival records based on their chemical and mechanical stability. Three categories of archival records based on their chemical stability are listed. Stack Management UV filters are available in many formats such as acrylic sheets, films, foils and as a coating. The UV absorbing lifespan of these materials varies with the filter type. Acrylic sheets may have a lifespan of up to 10 years whereas coatings and films should be checked around the five-year period.  UV Filters UV filters are available in many formats such as acrylic sheets, films, foils and as a coating. The UV absorbing lifespan of these materials varies with the filter type. Acrylic sheets may have a lifespan of up to 10 years whereas coatings and films should be checked around the five-year period. All UV filters should be checked with a UV monitor on a scheduled basis. Light Monitoring Equipment Lux Meter A lux meter is used to monitor light levels. Lux is a unit used to measure the intensity of the light source – technically one lumen per square meter. A 150W incandescent bulb gives a light intensity of about 50 lux at a distance of one meter. If a lux meter is not available, light levels can be measured using a built-in light meter on a SLR (single lens reflex) camera. UV Meter A UV meter is used to measure the amount of UV light being emitted from the light source. UV meters measure in units of microwatts/lumen. A reading of below 75 microwatts/lumen is considered acceptable for exhibition purposes. UV meters are Stack Management Low Cost Solutions Storage area Keep all archival materials covered or boxed when not in use. This is one of the simplest and most inexpensive solutions to the problem of light. Use blinds to eliminate sunlight Window glass filters UV light below 330 nm – apply UV filter film to windows to reduce UV light above 330 nm. Select fluorescent tubes with low or no UV emissions or use UV filters on the tubes. Selectively removing fluorescent tubes will reduce the overall light levels. “Dummy” tubes may have to be installed to ensure that the unit still works. Turn lights off in the archives storage area when not in use – timers, motion sensors or shut-off switches can be installed to ensure that the light are off when no one is in the storage area.  Mold  Mold and mildew are problems commonly associated with archival collections stored in humid locations with poor air circulation.  Can leave disfiguring stains on records and in severe cases render the document unreadable.  Growth occurs when relative humidity levels rise above 65 – 70% for 48 hours or longer.  Growth can occur over a wide range of temperatures – with most species growing between 4°C and 30°C.  Uses cellulose, gelatin, sizing and starch adhesives as nutrients.  Working with moldy records can pose health risks.  Ensuring the health and safety of staff, volunteers and researchers should be your main priority.  What to Do  Ensure that the relative humidity remains below 65– 70%.  Maintain some air circulation within the archival storage areas.  Inspect new acquisitions for mold prior to introducing the to the storage area.  Check the storage area for damp microenvironments.  Check the storage area for damp microenvironments. These are often located near exterior walls and windows.  Insulate cold water pipes located in storage areas to avoid condensation. Pollutant s Airborne contaminants occur in the form of gases and particulates which can seriously jeopardize the preservation of archival collections. Sulfur dioxide, nitrogen dioxide and ozone are the primary sources of gaseous pollutants. Calculation of Parts per Million (ppm) and Parts per Billion (ppb) Concentrations  Monitoring of gaseous and particulate pollutants requires specialized equipment. Monitoring should be undertaken by a trained engineer, conservator, or consultant. What to Do – Low Cost Solutions Keep doors and windows closed Use materials known to be benign to collections Check and replace air filters/scrubbers on a regular basis Air intakes should be located in as “clean” a location as possible