Colour Fastness Is Not One Score: Washing vs Rubbing vs Light for Home Textiles

Short answer: colour fastness is not one score. Washing, rubbing and light expose a textile to different stresses and answer different buyer questions. A fabric can keep its shade after laundering yet transfer colour when rubbed, or resist dry rubbing but fade under daylight. A defensible home-textile specification therefore names the exposure, test method, specimen state, assessment scale and acceptance rule instead of requesting “good colour fastness.”

For B2B bedding and home-textile sourcing, Nantong Oulai Trading Co., Ltd. recommends building the test package from the end use. Bed sheets and duvet covers usually need laundering and rubbing evidence; curtains and sunlit decorative textiles may also require light-fastness evidence. Printed, yarn-dyed and solid-dyed fabrics should be compared under the same agreed method and conditions. The dye or print route alone does not prove a grade.

What does each colour-fastness test actually answer?

Test	Buyer question	Typical evidence	What it does not prove
Washing fastness	Will the specimen change colour or stain adjacent materials during the specified laundering procedure?	Colour change and staining assessments after the stated ISO 105-C06 condition	Resistance to rubbing transfer or long-term daylight exposure
Rubbing fastness	Can colour rub off onto another material under the specified dry or wet condition?	Staining of the rubbing cloth under ISO 105-X12	Shade retention after detergent, heat and laundering action
Light fastness	How does colour respond to a controlled artificial light exposure representative of daylight?	Result under ISO 105-B02 and its declared exposure/assessment system	Performance in washing, wet rubbing or the exact conditions of every room

ISO 105-C06 covers domestic and commercial laundering procedures for normal household articles using a reference detergent. ISO 105-X12 addresses colour rubbed from textiles and staining of another material. ISO 105-B02 uses a xenon-arc source representative of daylight. These are separate methods; passing one cannot be used as evidence for another.

Why must a wash-fastness request name the exact condition?

“Wash fastness” is incomplete because the laundering procedure changes the severity of exposure. A useful request identifies the selected ISO 105-C06 procedure, temperature, detergent system, mechanical action, specimen construction and assessment criteria. ISO notes that single and multiple tests are not identical in severity, and that the specified detergent and bleach system matter. A laboratory report should therefore show the actual procedure rather than only a grade.

Buyers should also separate colour change from staining. Colour change describes what happened to the tested specimen. Staining describes colour transferred to adjacent fabric. ISO 105-A02 defines the grey scale for assessing change in colour, while ISO 105-A03 defines the grey scale for assessing staining. A specification that lists one number without identifying which assessment it represents is ambiguous.

Why should dry and wet rubbing be reported separately?

Dry and wet rubbing are different conditions and should not be collapsed into a single “crocking” value. Wet contact can create a different transfer risk from dry contact, especially for deep shades, printed surfaces or products used against pale bedding components. The report should state the direction tested when relevant, the face or surface tested, and whether the result is dry or wet.

For pile or textured fabrics, specimen preparation and contact with the rubbing cloth require particular care. The buyer should identify the usable face and pattern area to be assessed. A result from a flat background area may not represent a raised print, metallic-looking decorative surface or pile tip.

When does a home-textile buyer need light-fastness evidence?

Light fastness becomes more important when the finished product is expected to receive sustained daylight—for example, curtains, cushion covers near windows, bedspreads in bright rooms or decorative throws used in sunlit interiors. ISO 105-B02 evaluates response to artificial light representative of daylight, but the method does not reproduce every combination of glass, exposure direction, temperature, humidity and use duration.

For ordinary bed linen used away from prolonged sunlight, washing and rubbing may be the higher-priority risks. For a curtain program, light exposure may move into the core specification. The correct matrix follows the use case, not a universal list copied from another product.

How should buyers write colour-fastness requirements into an RFQ?

1. Define the finished use: sheet, duvet cover, pillowcase, curtain, cushion, throw or sleepwear.
2. Identify the colour system: solid-dyed, yarn-dyed, printed or a combination, without assuming that the route guarantees performance.
3. Name each exposure: laundering, dry rubbing, wet rubbing and/or artificial light.
4. Name the method and condition: include the part number, selected procedure, specimen face and any required preconditioning.
5. Separate outputs: colour change, staining of adjacent fabric, dry rubbing and wet rubbing.
6. Set application-specific limits: agree the grade or decision rule contractually; the method itself does not create a universal pass value.
7. Define sampling: colourways, darkest shade, print area, lot, roll and pre- or post-wash state.
8. Require traceability: link the report to the article number, colourway, sample ID, production lot and test date.

How can live fabric examples be used without overclaiming?

Oulai’s active catalogue includes Reactive Printed Cotton Fabric for Bed Linen, 100% Cotton Solid Dyed Fabric for Bedding and Home Textiles, and Solid Dyed Microfiber Fabric for Bed Covers and Sleepwear. These product pages help buyers frame sample and end-use discussions, but a material name, colour route or product description is not a colour-fastness result. Request evidence for the selected colourway and order.

The same boundary applies to the merchant-provided SGS report SL42604345449801TX: its washing and rubbing results apply only to the identified white woven cotton sample tested in that report. They cannot be generalized to the live examples above, other colours, prints or future lots.

Which internal guides help complete the specification?

Use How to Approve Fabric Color for Bulk Production for lab dips, instrumental colour difference and shade control. That process controls initial colour agreement; it is not a substitute for fastness testing. For a product-specific print workflow, see Reactive Printed Cotton for Bed Linen & Sleepwear. For report identity and scope, use How to Verify a Textile Test Report Before Bulk Approval.

Buyer checklist

• Have we defined the real exposure rather than asked for “good fastness”?
• Are washing, dry rubbing, wet rubbing and light listed separately?
• Does the report identify the exact method and selected condition?
• Are colour change and staining reported as different assessments?
• Were representative colourways and pattern areas sampled?
• Is the tested specimen traceable to the intended production lot?
• Are acceptance limits agreed before testing?

FAQ

Does reactive printing guarantee high wash fastness?

No. “Reactive printed” identifies a colouration route, not a verified result for every colourway, recipe, fixation condition or lot. Use the specified method on a traceable specimen.

Can one colour-fastness grade cover both colour change and staining?

No. They are different observations and should be identified separately. ISO 105-A02 addresses change in colour; ISO 105-A03 addresses staining.

Is light fastness necessary for every sheet program?

Not automatically. Select it when daylight exposure is material to the end use or claim. Laundering and rubbing may be more relevant for many sheet programs, while curtains and decorative textiles may need light evidence.

Can a report for one white cotton sample support a dark printed fabric?

No. Results remain tied to the tested sample and conditions. Fibre name alone does not establish equivalence across dyes, prints, shades, finishes or lots.

Authoritative Sources

• ISO 105-C06:2010 — Textiles — Tests for colour fastness — Part C06: Colour fastness to domestic and commercial laundering
• ISO 105-X12:2016 — Textiles — Tests for colour fastness — Part X12: Colour fastness to rubbing
• ISO 105-B02:2014 — Textiles — Tests for colour fastness — Part B02: Colour fastness to artificial light: Xenon arc fading lamp test
• ISO 105-A02:1993 — Grey scale for assessing change in colour
• ISO 105-A03:2019 — Grey scale for assessing staining
• ISO 105-A01:2010 — General principles of testing