Colour Failure
Since earliest time fabrics have been enhanced by the addition of colour. Collared fabrics are produced in several different ways. Some fabrics are woven from dyed yarns, some fabrics are dyed after weaving, and some fabrics are collared by printing the surface, often with several different colours. Modern technology has brought great improvements in colour performance, but colour failures may still occur from a variety of causes.
Colour Loss in Dry Cleaning
Some dyes are soluble in dry cleaning solvent. This may result in severe colour fading if such an article is dry-cleaned. If two or more dyes have been used and only one is solvent soluble, a dramatic colour change can occur. For example, the yellow component may be removed and leave a green garment blue. The only clue of the former colour may be the thread, which was dyed by a different method.
The same colour on two different garments may also be affected differently. For example, you may buy a dress with a coordinated jacket in a blue and white print. When they are dry-cleaned, the dress, which was vat dyed, may be unaffected, while the blue print of the jacket may fade so the blues no longer match.
Colour failure is frequent in household items such as bedspreads and draperies. Often the fading does not appear severe, but it can be very noticeable when the item is compared with a matching item. For this reason, matching bedspreads and draperies should all be cleaned at the same time.
Water-Soluble Dyes
Some dyes bleed when wet. This can occur in laundering or simply upon exposure to perspiration, rain, or water spillage. Some stains require water and water-soluble chemicals for removal, so even a dry-cleanable item should have dyes with some resistance to water.
Sizing Disturbance
Fabrics often have sizing to give them body. Sometimes water spills can cause sizing to migrate and form dark rings or streaks as it dries. This can be a problem with rayon, which is often heavily sized. Sizing can also become lightened on exposure to water. These discolorations are difficult to remedy on dry-cleanable fabrics because they require additional water to remove the sizing build-up, and this may aggravate the problem.
Crocking
Crocking is the rubbing off of colour from the fabric surface. Crocking may occur from wear alone, along edges of hems and creases. Crocking can also occur in washing or dry cleaning. This phenomenon is expected in some garments, such as denims, but the technology exists to produce deep colours that do not streak or fade.
Fading from Light Exposure
Eventually most dyes fade on exposure to light, especially sunlight. But sometimes colour failure occurs rapidly on exposed areas such as shoulders, collars, and sleeves. Usually sunlight is the cause, but artificial light can also cause fading. Many blue, green, and lavender dyes are particularly light sensitive, especially on silk and wool fabrics. .
Chemical Damage
Many common substances found in any household can cause chemical changes to dyes. Exposure to perspiration or to alkaline substances, which are present in many toiletries, can cause colour change. Dyes used on silk can fade on exposure to alcohol. Even acid from lemon juice can cause bleaching on some dyes. And spillage of chlorine bleach is a very common cause of colour loss and even fabric damage.
Fume Fading is the result of a chemical change in the dyestuff. Acid gases that form in the atmosphere as a product of combustion react with some dyes to cause a gradual colour change. This type of change can occur even while a garment is stored in your closet. It is usually not uniform, but is more noticeable on exposed areas such as shoulders and sleeves. Sometimes this type of colour change may not be noticed until after washing or dry cleaning, but these immersion processes cannot cause this localized type of change. Fume fading is most common on acetates.
Whites White is actually a colour, too. In their natural state, many fabrics have an off-white or yellowish cast and are therefore often bleached to remove this natural colour. In addition, many white fabrics are treated with whiteners during manufacture. These optical brighteners, also called florescent whitening agents, change the reflective quality of the fabric to make it appear whiter and brighter.
Different brighteners are used with different types of fabric. Some of these agents are unstable and may break down and lose their whitening power, so that the fabric reverts to a yellowish or greyish appearance. Some fabrics may take on a pinkish or greenish blue. When a fluorescent brightener breaks down due to light exposure, the unexposed areas will be unaffected. For example, the front of a sweater laid out to dry in the sun may turn yellow while the back remains white. Brighteners are especially sensitive to light exposure when garments are wet. This is why some care labels specify drying out of direct sunlight.
Another cause of yellowing of white may be resins added to impart a permanent press quality. These resins can yellow when they are exposed to chlorine bleach. In this case, the yellowing will be uniform. It can be avoided by following the care label and using only non-chlorine bleach when this is specified.
Some white fabrics lose their whiteness just from normal oxidation and exposure to atmospheric soils. This process can be reversed in some fabrics by careful wet cleaning and bleaching, but often yellowing is not reversible. Drycleaners sometimes add a fluorescent brightener to their dry cleaning procedure, and many laundry detergents include brighteners, but severe cases of yellowing cannot be corrected in this manner.
