Color Fastness in textiles: an in-depth guide
Color Fastness is a well-known textile industry term which relates to the resistance of a material to a change in any of its colour characteristics. The term was coined in 1916 by the textile industry whereby manufacturers tested fabrics when exposed to light, washing, perspiration, and abrasion.
Color Fastness remains as relevant as ever and, as this article will show, there are now standards to rate fabric behaviour when exposed to testing.
Color Fastness can be defined in several ways. The first is the ability of a fabric to retain its original dye color under the influence of various external factors in the normal use of dyed textiles. Another definition relates to the resistance of color of a dyed or printed textile to fade or bleed under different types of influences including water, light, rubbing, washing and perspiration.
There are different degrees of colorfastness and for this reason fastness properties are expressed in ‘ratings’, from rating 5, which means unchanged to rating 1, which means major changes to color.
Color Fastness after exposure to light is measured using a specimen of the fabric to be tested. The specimen and a range of eight blue wool standards are simultaneously exposed to artificial light in an apparatus fitted with a xenon arc fading lamp with the humidity in the apparatus is controlled.
Blue wool references are identified by the number 1 (very low colour fastness) to 8 (very high colour fastness), with each rating being approximately double the fastness of the one below it. The term ‘change in colour’ includes changes in hue, chromatic characteristics, lightness or a combination of these characteristics of colour.
Human health element
Why is Color Fastness so important? The issue is that when when fabrics with poor color fastness are exposed to water, sweat, sunlight or physical friction, the dyes may eventually fall off or fade, and this in turn means the appearance of the textile product is negatively affected. There is also a human health element as, during use, shed dye molecules or heavy metal ions may be absorbed by the human body through the skin, thereby endangering the user’s health.
So what factors affect whether or not fabrics are likely to retain their color or bleed easily? Textile chemists recognise there are many issues which can impact these issues.
They include the content of a fabric, as each fibre has different properties. To offer one example, polyester is usually more colorfast than nylon.
Another variable is natural dyes versus synthetic dyes. The textile industry has seen a shift towards natural dyes by some of the major textile chemical companies in recent years, although these are not always as cost effective and more difficult to scale.
While natural dyes can have a tendency to fade faster than synthetic dyes, because they fade over time they stay true to their original color, with the colors becoming softer and acquiring a patina. Synthetic dyes tend to be more color fast, but when they do get to the point of fading they can fade to a different or muddier color than that of the original. As an example, navy blue could fade to a gray, or orange to beige.
Other factors which influence colorfastness include whether or not fibres were dyed before the weaving or knitting process or if the finished fabric was vat-dyed; the laundry chemicals used during cleaning, including detergent, stain removers, or bleach; the water temperature used for washing (higher temperatures may cause problems for some garments); the pH of various substances which interact with the fabric (perspiration, detergents, or skin creams); and whether the fabric is exposed to high drying temperatures.
If this sounds like a complex issue, that’s because it is. There are many variables involved in Color Fastness and clothing manufacturers may not always be inclined to include full information on garment labels regarding whether or not clothing is going to bleed.
That said, if a label says “wash separately” or “wash with similar colors,” that would offer an indication that a dye was not stable and is likely to bleed or even rub off. To offer an example, jeans can turn a light-colored cushion blue because the dye rubs off.
Is there a test for color fastness? Actually, the colour fastness of textiles is graded by discoloration and staining grey cards. The cards currently in use include AATCC grey cards, ISO grey cards, JIS grey cards and national standard GB grey cards. These grey cards are only slightly different in the grayscale.
The Color Fastness rating grey card is a card characterized by a specific gradient increase or decreases. A color-changing grey card comprises one group of standard grey levels and another group of color-changing grey levels. The original grey levels remain unchanged throughout a test, while the second group of color-changing gray levels decreases gradually to form a discoloration contrast between the two.
Testing for Colour Fastness
A leading name in apparel testing and quality control is HQTS. HQTS provides quality control inspections, factory audits, supplier evaluations, consumer product testing, production control and management, and quality control consulting throughout greater Asia.
HQTS is accredited to test against all major regulatory standards for the import of consumer products, including fashion and footwear.
HQTS boasts 80,000 sq ft of laboratory, centrally located in Hangzhou, China. From this base, the company provides competitive pricing, fastest delivery times in the industry, and the support of a single point of contact for all testing projects. This personalized approach has established it as one of the most respected labs in China.
HQTS can test for compliance against RoHS, REACH, ASTM, Ca Prop 65, EN 71, to name a few.
Setting the standard
HQTS has been setting the standard in reliable textile and apparel quality control services throughout Asia since 1987. The business offers comprehensive services for all your apparel and textile inspections and testing to help clients deliver the highest-quality products.
With nearly 700 professional staff in Asia, HQTS textile and apparel inspections are conducted by industry educated and experienced experts that can evaluate textile products and help clients to identify varying levels of defects, including colour fastness issue.
HQTS vastly experience inspection, scientific and engineering staff provide unparalleled guidance for even the most complex product performance needs. The company’s knowledge, experience, and integrity helps clients to achieve compliance with international regulations on flammability, fibre content, care labelling and more.
The textile testing laboratory of HQTS is equipped with advanced testing equipment and processes. The business provides high quality testing service against most international standards, including:
Visual Inspection – Ensuring a product meets or exceeds client expectation with special emphasis on color, style, materials, helping to ensure market acceptance
AQL Inspection – HQTS staff work with clients to determine the best AQL standards to maintain balance between cost of services and market acceptance
Measurements – HQTS boasts a well-trained inspection team which will inspect a client’s entire shipment prior to shipping to ensure compliance with their measurement specifications, avoiding loss of time, money, and goodwill due to returns and lost orders.
Testing – HQTS-QAI has been setting the standard in reliable textile and apparel testing services since 2003. The company’s veteran scientific and engineering staff provide unparalleled guidance for even the most complex product performance needs. HQTS’ knowledge, experience, and integrity helps clients achieve compliance with international regulations on flammability, fibre content, care labelling and many more related issues.
With increasing concern regarding the environmental, health and safety of textiles, and successive introductions of relevant governmental regulations, textile manufacturers are facing unprecedented challenges in quality assurance. HQTS-QAI has a team of professional testing engineers who provide one-stop textile testing services in accordance with ASTM, AATCC, ISO, EN, JIS, GB plus others. HQTS internationally recognized testing services help clients to improve the quality of their products and meet specific regulations
Major product categories
- Various fibrillar component
- Various structural fabrics
- Home textiles
- Decoration articles
- Ecological fabrics
Physical testing items
- Fiber composition analysis
- Fabric construction
- Measurement stability (shrinkage)
- Color fastness
- Flammability safety
- Garment accessories (zipper, button, etc.)
Chemical testing items
- Allergenic disperse dyes
- Carcinogenic dyes
- Heavy metal
- Flame retardants
- OPEO: NPEO, CP, NP
Other quality control services
HQTS services a wide range of consumer goods including
- Automotive parts and accessories
- home and personal electronics
- Personal care and cosmetics
- home and garden
- Toys and children’s products
- Bags and accessories
With regards to Color Fastness testing, a variety of different national and international standards may apply to a product, including:
Color Fastness to Washing (ISO 105 C06)
ISO 105-C06 specifies methods intended for determining the resistance of the colour of textiles of all kinds and in all forms to domestic or commercial laundering procedures used for normal household articles using a reference detergent. Industrial and hospital articles may be subjected to special laundering procedures which may be more severe in some aspects.
Color Fastness to Light (ISO 105 B02)
ISO 105-B02:2013 specifies a method intended for determining the effect on the colour of textiles of all kinds and in all forms to the action of an artificial light source representative of natural daylight (D65). The method is also applicable to white (bleached or optically brightened) textiles. This method allows the use of two different sets of blue wool references. The results from the two different sets of references may not be identical.
Color Fastness to Phenolic Yellowing (ISO 105 X18)
Although fabrics may turn yellow under a variety of circumstances, one of the most frequent culprits is the plastic packaging in which the fabric is stored. Phenolic acid is commonly used in industrial plastics and can sully material when exposed to oxygen.
ISO 105-X18:2007 specifies a method intended for assessment of the potential to phenolic yellowing of textile materials. The method is specific to phenolic yellowing and does not cover the many other possible causes of yellow discolouration found on textile materials.
Color Fastness to Rubbing (ISO 105 X12)
ISO 105-X12:2016 specifies a method for determining the resistance of the colour of textiles of all kinds, including textile floor coverings and other pile fabrics, to rubbing off and staining other materials. The method is applicable to textiles made from all kinds of fibres in the form of yarn or fabric, including textile floor coverings, whether dyed or printed. Two tests may be made, one with a dry rubbing cloth and one with a wet rubbing cloth.