What Is Light?
Lightfastness testing is the exposure of the sample to artificial sunlight produced by a xenon arc lamp under controlled temperature and humidity. Along with the sample, blue wool reference strips are also exposed to the same conditions; The fading in the sample is graded from 1–8 depending on which blue wool reference fading corresponds to it.
Purpose of Light
The aim is to comparatively determine how long the product will retain its color under sunlight. It is decisive in curtains, upholstery and vehicle interior textiles.
Which Products Is Light Applied To?
- Curtain and sunshade fabrics
- upholstery fabrics
- Automotive interior textiles
- Outdoor textiles and awnings
- Printed textiles
In Which Sectors Is Light Used?
Standards Related to Light
- TS EN ISO 105-B02 (artificial light — xenon arc)
- TS EN ISO 105-B04 (artificial air conditioning)
- TS EN ISO 105-B06 (high temperature artificial light — automotive)
- AATCC 16
- TS EN ISO 105-A02 (color change scale)
Light Conditions
- Light source
- Xenon arc, with filter system defined in the standard
- Reference
- Blue wool scale (1–8); the sample is exposed along with the reference
- Cabin conditions
- Black panel temperature and relative humidity are controlled according to standard
- Maruz kalma
- Maintained until target blue wool level fade
Equipment for Light
- Xenon arc light fastness tester
- Blue wool reference scales
- Siyah panel/siyah standart termometre
- Standard illuminated evaluation cabin and gray scale
Sample Requirements for Light
- The sample must be cut to the size defined in the standard
- A separate specimen for each colour
- A portion of the sample is masked and preserved as a reference
- Automotive specifications require separate samples and separate standards
Duration of Light
The duration depends on and is directly determined by the targeted level of blue wool: low levels last days, high levels take weeks. That's why light fastness is one of the longest-lasting textile tests.
Light Procedure
- 1Samples and blue wool references are placed together in the cabinet.
- 2A portion of the sample is masked, preserving the unexposed reference.
- 3Cabin conditions (temperature, humidity, radiation) are adjusted.
- 4Exposure is continued until defined fading is observed in the targeted blue wool reference.
- 5The sample is removed and conditioned.
- 6Blue wool grade is determined by comparing the masked and exposed area.
Light Acceptance Criteria
The acceptance criterion is the minimum blue wool grade in the specification. While high grades are required for curtains and upholstery, lower grades are acceptable for daily wear. The standard does not define a passing grade.
Evaluation of Results
The result is given as a blue wool rating from 1 (very low) to 8 (very high). The scale is logarithmic: each digit means approximately twice as long strength, so the difference between 5 and 6 is not small.
Light Report
- Sample description and color
- Applied standard section and filter system
- Cabin conditions and total radiation
- Blue wool grade
- Gray scale color change note if any
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- EU 1007/2011 (textile fibre names and labelling)
- EU 1907/2006 REACH Annex XVII (restricted substances in textiles)
- Regulation on the Naming of Textile Products
Tekstil Testleri — What Does This Testing Field Cover?
The section below describes the field that the Light test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Textile testing answers two questions separately: does the fabric hold up physically over its service life, and does it carry any substance restricted for human health? These two axes require different laboratory infrastructure and different decision mechanisms.
On the physical side, breaking and tear strength, abrasion resistance, pilling, dimensional change, colour fastness and water and oil repellency are measured. Most of these tests depend on the USE SCENARIO: Martindale abrasion cycles are decisive for an upholstery fabric, while dimensional change in washing and colour fastness come to the fore for a shirting fabric. The same fabric goes through a different test set for a different use.
Colour fastness is a body of work of its own in this field and is not a single test. The fastness of the same fabric to light, washing, rubbing, perspiration, saliva, chlorinated water and ironing is measured separately; each represents a different moment of use. Results are rated from 1 to 5 on the grey scale and the specification gives a separate minimum rating for each agent.
On the chemical side, aromatic amines released from azo dyes, formaldehyde, heavy metals, phthalates, short-chain chlorinated paraffins, alkylphenols and PFAS compounds are screened. These items come from REACH restrictions, brand restricted substance lists (RSL) and voluntary schemes such as OEKO-TEX. Brand lists are often stricter than legislation; the target customer is decisive.
There is NO CE marking on consumer textiles. The obligation has three legs: fibre composition and care labelling, compliance with chemical restrictions, and general product safety. Textiles claiming a protective function (workwear, flame-resistant clothing, high-visibility clothing) fall under personal protective equipment legislation, where CE is mandatory — this distinction is commercially critical.
Verifying the label declaration is the most routine work in the field. Quantitative fibre analysis confirms the blend ratio stated on the label; tolerance ranges are defined in legislation. An incorrect fibre declaration both misleads the consumer and affects customs classification.
Sustainability claims have added a new body of work to the field in recent years: verification of recycled content (GRS, RCS), organic content (GOTS), restriction of harmful chemicals and water/energy footprint declarations. These claims now require auditable evidence.
Method groups in this field
Strength and durability
Strip and grab breaking strength, tearing by the Elmendorf and tongue methods, seam strength, bursting strength.
Abrasion and surface
Martindale and rotary platform abrasion, pilling and fuzzing, fabric mass and thread density measurements.
Dimensional stability
Dimensional change in washing and drying, wrinkling behaviour, appearance after ironing.
Colour fastness
Fastness to light (xenon), washing, rubbing, perspiration, saliva, water and chlorinated water; rating on the grey scale.
Functional properties
Water repellency (spray test), oil repellency, waterproofness, air permeability, effectiveness of antibacterial finishes, UV protection factor.
Chemical analyses
Aromatic amines from azo dyes, formaldehyde, pH, heavy metals, phthalates, chlorinated phenols, PFAS and alkylphenols.
Commonly confused in this field
- A brand restricted substance list (RSL) may be stricter than legislation; REACH compliance does not mean compliance with the customer specification.
- Textiles claiming a protective function fall under PPE legislation and require CE; an ordinary textile test report does not satisfy that file.
- Colour fastness is not a single number; a rating cannot be interpreted without stating which agent it relates to.
- A result obtained for a fabric does not cover the whole garment made from it; lining, sewing thread, print and trims are assessed separately.
- Performance claims after washing are valid together with the stated number of wash cycles; the word "permanent" on its own is not verifiable.
Which decisions these results support
- Compliance with the brand restricted substance list (RSL)
- Verification of label declarations: fibre composition and care instructions
- Determining the performance class of upholstery and technical textiles
- Pre-import shipment inspection and lot acceptance
- Supporting sustainability and recycled content claims
Related Tests
Frequently Asked Questions About Light
What is the blue wool scale?
It is eight strips of blue dyed wool with known light resistance. Each strip lasts about twice as long as the previous one. Since the sample is exposed to light simultaneously with these strips, the result becomes independent of cabin differences.
Does the same test apply to automotive?
Usually not. Temperature and radiation conditions inside the vehicle are more severe; ISO 105-B06 and OEM specifications are used for this. The B02 result obtained for clothing does not represent in-vehicle application.