fade to grey — Degradation of dye structures
The methods of textile conservation apply to a wide range of items, including tapestries, w2w carpets, area rugs, quilts and window treatments, as well as objects which 'contain' textiles, such as upholstered furniture, wall treatments, and accessories such as fans, parasols, or room screens, lamp shades.
Many of these artifacts require specialized care, often by a professional cleaner and or a conservator.
The goal of this document is to provide a general overview of the process of colour degradation (fade).
Always contact a professional if you need specific questions answered.
Colours will fade over time
Knowing how to properly care for your textiles helps ensure a long and enjoyable relationship with them.
Many factors contribute to colour degradation. These agents of deterioration can occur naturally, or they can result from external forces. Avoiding agents of deterioration is the key role of preventive care.
The agents that affect colours most are:
- light (visible, infrared and UV)
- fabric
- temperature
- humidity
- chemicals
- pests
Light
Light can have a variety of effects on colour over time. Visible light contributes to fading and discoloration, but of more concern is the damage which colours may suffer under prolonged exposure to non-visible light, such as ultraviolet and infrared lighting. Ideally, colours should be exposed too as little light as possible, and preferably exist in total darkness. However, in real-world situations this is highly impractical.
Natural light is the most common source of ultraviolet light, and as such, care should be taken to avoid exposure to direct sunlight at all costs. If a room relies on natural light, UV screens or coatings can be applied to the windows to block harmful rays while still allowing light to pass through. Carefully chosen window treatments designed to block light from fabrics will help.
Fluorescent and halogen, tungsten produced light (hid ... high intensity discharge ) can also produce large amounts of UV radiation, though filters which fit over the bulbs are available to limit the damaging light.
One advantage of fluorescent lights is that they produce little heat, which may also be harmful to textiles. Incandescent lights produce a large amount of heat in addition to large quantities of infrared radiation, which is likewise damaging to the dyes of antique textiles. If incandescent lights must be used, they should be placed far enough away from fabrics that their heat cannot be felt.
In some installations , you may consider motion-activated or timed lighting, which would allow the textiles to remain in limited light when they are not in use.
How fabrics change over time.
As all textiles age, they slowly break down and constantly deteriorate. Basically the deterioration of textiles is the gradual breaking down of long chain fiber molecules into shorter chains. The result is brittleness. Other forms of natural deterioration are:
gradual loss of inherent moisture — Natural fibers come from living sources with biological functions. As they age and the structure of the fiber changes, fibers become less elastic and resilient.
effects of impurities — The presence of small amounts of metals, such as copper, can accelerate deterioration in the presence of bleaching agents, ozone, ultraviolet radiation, and moisture.
impact of manufacturing — Metallic mordant's, oils and lubricants used to facilitate the weaving process, and bleaching are some of the manufacturing processes that can contribute to the deterioration of textiles.
inherent vice — Sometimes methods of manufacture and the nature of materials cause deterioration that cannot be controlled and may not be treatable. The most striking example of inherent vice is the impact of the addition of certain metallic compounds to silks to add weight and drape to silk fabrics. These compounds bond to the silk fiber and cause their eventual splitting and powdering. Another example is the interaction of some metal threads and decorations with textiles. The natural deterioration of wool accelerates deterioration of silver metallic threads causing tarnish. The tarnish can then stain the wool.
oxidation — Fabrics are naturally degraded by the presence of oxygen. The result is an overall brownish discoloration on white or natural coloured textiles.
Temperature and Humidity
Temperature and humidity can both contribute to colour degradation.
Excessive dryness causes damage, especially to the dye sites of elastic fibers, such as wool, which rely on a certain amount amount of moisture to maintain their integrity. Temperature and humidity should be kept as constant as possible; changes in either of these may cause fibers to expand and contract, which, over time, can also cause damage and deterioration of colours. Excessive moisture can supply an environment wherein unwanted chemical reactions can occur more easily.
Ideally, temperature should be kept around 70 degrees Fahrenheit though some slight fluctuation in either direction is permissible, as long as it occurs gradually For instance, temperature may be slightly lower in winter to save energy costs, but any change should be affected slowly, over a day or so, so as not to place the fabrics and hence the colours under undue stress.
As for humidity, a relative humidity of 30% - 50%, though, some small fluctuation is allowable, as long as it occurs gradually.
In areas where climate control is unavailable (such as in historic buildings), you can still moderate the temperature and relative humidity through use of fans, humidifiers and dehumidifiers, and portable heating or cooling units.
Air flow is also a concern for colour preservation.. Proper circulation, combined with the suggested humidity, will help to prevent the growth of mould and mildew, which may stain or weaken delicate or antique textiles.
What kinds of chemicals can affect colours?
Outdoor pollutants, such as dust and pollen, can easily be brought into a site through open doors and windows. Industrial emissions as well as natural processes of erosion create pollutants. Cleaning products, building materials, paint, carpeting, and other indoor materials can generate pollution from within a site. Cigarette, cigar, and pipe smoke are also harmful forms of pollution.
Dirt disfigures fabrics, dulls colours, and often stains. Dirt and dust also contain a high proportion of silica dust. The sharp surfaces of this silica can cut and abrade textile fibers, damaging dye sites, especially when the fibers expand and contract in response to changes in humidity.
Sulphur dioxide bleaches, discolours, and embrittles textiles. Hydrogen sulphide in the presence of moisture darkens lead pigments, tarnishes metals threads, and reacts with finishes and some embellishments. Formaldehyde found in some in paints, varnishes, wood products, and adhesives found in furniture and in carpeting can damage some dyes. Tar and particulates from tobacco products stain textiles and are difficult to remove.
Household cleaners containing ammonia, borates, perborates, harsh aggressive detergents, products that are extremely acidic or alkaline in nature all will cause damage to dye structures.
Improper maintenance performed by well meaning but under educated cleaners is perhaps one of the most frustrating causes of colour damage. Proactive programs of fabric care go much further then knee jerk reactive processes in maintaining colour. Stain protective treatments go a long way in helping to preserve colour.
Pests
Pests are another source of colour damage. Among the most common are clothes moths, carpet beetles, silverfish, and rodents.
Clothes moths are attracted to protein fibres, and so are especially drawn to silk, wool, and feathers. An infestation might be identified through the evidence of white cocoons (or the remnants thereof) on the fibers, or sighting the insects themselves. They are roughly 8 centimetres long and white in colour.
Like clothes moths, carpet beetles are likewise drawn to proteins, and can be quite destructive. Evidence of an infestation may take of the form of chewed holes, carcasses, or larvae, which appear as small pale worm-like insects.
Silverfish consume starch, usually found in sizing or other treatments applied to fabrics, as well as plant-based textiles such as linen and cotton. They are attracted to dark, moist climates. Silverfish prefer cooler temperatures. Both are about 12 millimetres in length and either light or dark in colouring, depending on which type is present.
Rodent infestations can be identified in the usual ways, such as seeing droppings, nests, or comparatively large chewed areas of textile where they have caused damage.
In all cases, chemical means of pest control should be very carefully made use of, not only due to possible harm to humans who come in contact with them, but because the chemicals may cause damage to the dye structure of the fabric.
Fecal deposits, urinary excretions, digestive juices found in saliva, will all cause colour damage especially on unprotected fabrics and carpets
What can be done?
Colour is a part of our lives. Colour warms us, comforts us, and brings us enjoyment. Take a proactive stance in caring for their colours.
Ask a professional service company to help you get an individualized care program booklet and service plan ready and in place for your colours.
Protect the materials you have selected for a particular site with stain protective treatments that are colour safe and effective.
Make sure any Maintenance / Cleaning people are of the best calibre.
Always contact a professional if you need specific questions answered.
It is all about the environment ... really.