Conserving, Preserving, and Restoring Your Heritage. Kennis Kim
Читать онлайн книгу.
sorting and evaluation of historic documents and artifacts, including Help! I’ve Inherited an Attic Full of History by Althea Douglas, ullished by the Ontario Genealogical Society in 2003. Once you’ve determined what you have, it’s time to decide how you’ll care for these things. Before you do anything, you should document what you have both in a written format and photographically, if possible. An accession list of all your holdings, will help you to know what you have and where it is, and help you decide what you might do with it. An accession list, similar to an inventory, can be made using an index card for each item or in a list on paper or in your computer. Whatever method of compiling the information you use, always keep a hard copy in a safe place somewhere other than your home. Having an accession list and photographs of your items can be helpful in recovering stolen goods, filing insurance claims, and sharing information, images, or documents with others without jeopardizing the originals.
A basic accession list can be as simple as listing the items either in groups or individually. Include what it is, where it came from, and where it’s located in your home (see Appendix 1: Accession List Information). Additional information might include condition notes, value, if it’s insured, historic significance, supporting research, conservation reports, and any other information that may relate to the artifact. Photographs can be slides, prints, or digital files.
The decision to display, store, or continue to use an artifact should in part be based on the condition and structural stability of the object. If an item is stable and in good condition, you can prepare it at home for display or storage. However, if an item is damaged or fragile, it may be necessary to call a professional (see Appendix 2: How to Find and Choose a Conservation Professional). Choose the right professional for your artifacts by considering the type of items, their overall condition, and the intended use of the objects. Storage, use, display, or just ignoring things all have consequences.
CHAPTER 1 The Home Environment
What are conservation, restoration, and preservation?
Conservation is the examination, stabilization, reconstruction (restoration), and reduction of further deterioration (preservation) of an object. Conservation often includes:
• Scientific analysis of the object and the materials used during fabrication,
• Research into the structure and historic significance of an artifact, and
• Determination of overall condition and stability of the artifact.
Restoration refers to the reconstruction of the aesthetic appearance of an object. This is a small part of the conservation process.
Preservation is another small part of the conservation process that focuses on treatments to retard further deterioration of an object.
The most we are able to do in our homes are preservation and some basic preventative conservation. To preserve the structural stability and to slow deterioration of objects, you must pay attention to the environment, including light, temperature, and relative humidity, as well as the methods of handling, displaying, and storing the object.
Environmental Concerns
Light
All light is a form of energy. When light energy is absorbed by an artifact, it causes chemical changes in the molecular structure of the object. Natural and artificial light can damage objects by fading colours, yellowing varnishes, bleaching paper, and weakening textiles.
For our purposes, the light spectrum can be divided into three parts: infrared, ultraviolet, and visible light. Visible light is the part of the range of light between the ultraviolet and infrared parts of the light spectrum. Ultraviolet (UV) light is invisible. UV light falls beyond the blue portion of visible light. Infrared (IR) is also invisible. It falls just past the red portion of visible light.
Light is measured in foot-candles, lumens, or lux. You can determine an approximation of the number of lux at home using a single lens reflex (SLR) camera or a light meter (see Appendix 3: Using a Camera to Measure Approximate Light Levels).
Ultraviolet light is the most energetic form of light radiation and causes the most damage. To reduce UV damage, it is important to reduce UV exposure. You can do this in three ways:
1. Always use low-UV emitting light sources, such as incandescent bulbs. Tungsten-halogen lamps and fluorescent lamps (both traditional fluorescent tubes and the new energy-saving spiral bulbs) have higher UV output than incandescent bulbs but lower UV than natural daylight.
2. There are UV filters that block the UV from light sources such as fluorescent bulbs and on windows. UV filters come in the form of sleeves that slip over fluorescent tubes and films that can be applied to glass or windows. There are also plastics and glass for framing and display of artifacts with UV reducers incorporated into their structure.
3. Bouncing light off a painted surface will reduce much of the damaging UV energy in natural light.
Diagram 1: Reflecting light — a method of reducing the damage from UV sources
Infrared light (IR) is less damaging than UV because it has less energy, but it is more easily absorbed by the surface of an object. IR may be thought of as heat because it causes an object to warm up, which speeds chemical deterioration. Dark surfaces absorb heat more readily than light surfaces. To reduce heat build-up, avoid direct sunlight and move incandescent bulbs away from artifacts.
Visible light falls between the UV and IR portions of the light spectrum. Light that appears blue is closer to the UV end of the spectrum and is more damaging to artifacts. Examples of blue light sources are cool fluorescent lamps, full-spectrum fluorescent lamps, and sunlight. Warm fluorescent lamps have lower amounts of blue light and incandescent lamps have the lowest amount of blue light. UV filtered sunlight is far more damaging than the visible light emitted from an incandescent lamp. Never use picture lights mounted onto a frame; they are too close to the artifact’s surface. Never use direct spotlights that are closer than three metres to the artifact.
To reduce damage from visible light, you should reduce the amount of daylight and glare from glossy surfaces to produce lower light levels acceptable for viewing. This can be achieved by indirect lighting: either reflecting light off another surface or lighting from an angle. Light damage is cumulative and depends on the intensity of the light level as well as the length of exposure. Rotate light sensitive items that are displayed so that artifacts will have time to “rest” in dark storage.
Temperature
Heat, cold, and cycling of temperatures cause damage to artifacts. When an artifact is warmed, the rate of chemical reactions within the molecular structure increases. These reactions are the deterioration of the artifact. Ambient temperature and exposure to IR light sources such as daylight, incandescent lamps, or spotlights cause warming of an object. Darker objects absorb more energy and warm quicker than lighter surfaces. If an object heats, cools, or cycles through rapid changes of temperature of more than 10 degrees within a short period of time (one to two hours), the result can be significant dimensional change: expansion and contraction.
Relative Humidity
Relative humidity (RH) is a percentage representing the amount of water vapour in the air compared to the total amount of water the air can hold at that temperature. A relative humidity of 100 percent at a given temperature would refer to complete saturation of the air by the water vapour present.
Changes in the RH do not greatly affect most people’s comfort level but a temperature change of a few degrees does make a difference in how comfortable you feel. Art and artifacts react much more to changes in RH than shifts in temperature. It is much more important