ISO 105 Color Fastness to Perspiration Testing: Complete Technical Guide

ISO 105 color fastness to perspiration testing (ISO 105-E04) is the internationally recognized method for evaluating how textile dyes resist fading and staining when exposed to human sweat. This technical guide explains the test principle, sample requirements, procedure, evaluation criteria, and typical applications for textile manufacturers, quality control laboratories, and sourcing professionals.

Technical Overview

The ISO 105 series, published by the International Organization for Standardization, is the globally accepted framework for assessing the color fastness of dyed and printed textiles. Within this series, ISO 105-E04 specifically addresses color fastness to perspiration, one of the most frequently requested tests in commercial textile production. The method simulates prolonged contact between textile materials and human sweat by exposing test specimens to artificial perspiration solutions under controlled temperature, pressure, and duration conditions.

Human perspiration contains both acidic and alkaline components, and its composition varies between individuals, body regions, and activity levels. For this reason, the standard requires testing with two separate artificial sweat solutions: an acid solution buffered at pH 5.5 and an alkaline solution buffered at pH 8.0. The test evaluates two distinct failure modes: color change of the specimen itself and staining transferred to adjacent fabrics.

• Standard reference: ISO 105-E04 (Textiles — Tests for colour fastness — Part E04: Colour fastness to perspiration)
• Test temperature: 37 °C ± 2 °C, approximating human body temperature
• Exposure time: 4 hours under pressure
• Applied pressure: 12.5 kPa, equivalent to approximately 5 kg load on the specimen
• Liquor ratio: 50:1 (solution volume to specimen mass)
• Evaluation: grey scale ratings from 1 (poor) to 5 (excellent) with half-step increments

Testing Samples

Dyed and Printed Fabrics

Fabric samples are cut to 100 mm × 40 mm and placed in contact with a multifibre adjacent fabric of the same dimensions, or sandwiched between two single-fibre adjacent fabrics in accordance with the ISO 105-F series. One adjacent fabric should match the principal fibre of the specimen, while the second is typically polyester or another fibre as specified by the customer or product standard.

Yarns and Loose Fibres

Yarn samples are knitted into a small swatch or wound tightly around a suitable frame to form a uniform layer of the required dimensions. Loose fibres are combed and compressed into a thin, even sheet of matching size before being combined with the adjacent fabric.

Multicolored and Patterned Goods

When a fabric contains multiple colors, all significant colors must be included in the test. This may require preparing separate specimens so that each color is positioned in contact with the adjacent fabric, or ensuring the combined specimen captures all major shades of the design.

Sample Conditioning

Specimens and adjacent fabrics should be conditioned in a standard atmosphere of 20 °C ± 2 °C and 65 % ± 4 % relative humidity prior to testing to ensure reproducible moisture content and consistent results.

Testing Items

Testing under ISO 105-E04 covers the following assessments, each of which is reported separately for the acid and alkaline conditions:

• Color fastness to acid perspiration (color change of the specimen after exposure to pH 5.5 solution)
• Color fastness to alkaline perspiration (color change of the specimen after exposure to pH 8.0 solution)
• Staining of adjacent fabrics in acid perspiration (dye transfer measured against the staining grey scale)
• Staining of adjacent fabrics in alkaline perspiration
• Surface appearance changes such as bleeding at color boundaries in multicolored goods, where relevant

Testing Methods

Preparation of Artificial Perspiration Solutions

The acid solution contains 0.5 g/L of L-histidine monohydrochloride monohydrate, 5 g/L of sodium chloride, and 2.2 g/L of sodium dihydrogen orthophosphate dihydrate, adjusted to pH 5.5 ± 0.2 with sodium hydroxide solution. The alkaline solution contains 0.5 g/L of L-histidine monohydrochloride monohydrate, 5 g/L of sodium chloride, and 5 g/L of disodium hydrogen orthophosphate dodecahydrate, adjusted to pH 8.0 ± 0.2. Both solutions must be freshly prepared and used within a short period to avoid pH drift.

Test Procedure

• Immerse the combined specimen (fabric plus adjacent fabric) completely in the test solution for 30 to 60 minutes at a liquor ratio of 50:1, occasionally agitating to ensure thorough wetting.
• Remove the specimen and squeeze gently to remove excess liquor, retaining approximately its own mass in solution.
• Place the specimen between the plates of a perspirometer (perspiration fastness tester) so that a pressure of 12.5 kPa is applied uniformly across the specimen area.
• Place the loaded apparatus in a laboratory oven maintained at 37 °C ± 2 °C for 4 hours, regardless of whether one or multiple specimens are tested.
• After the exposure period, remove the specimen, open it out, and allow it to dry in air at a temperature not exceeding 60 °C, keeping the two parts in contact only at the stitching line.

Evaluation and Reporting

Color change of the tested specimen is assessed against the original sample using the grey scale for color change in accordance with ISO 105-A03, while staining of the adjacent fabric is assessed using the grey scale for staining in accordance with ISO 105-A02. Ratings range from 1 (severe change or staining) to 5 (no visible change or staining), with intermediate half-step grades such as 4-5 commonly reported. The test report should state the ratings for color change and staining under both acid and alkaline conditions, the adjacent fabrics used, any deviations from the standard, and the pH of the solutions before and after testing where required.

Applications

Perspiration fastness testing is a core requirement across nearly every category of clothing and many technical textile applications:

• Sportswear and activewear, where garments experience prolonged contact with sweat during exercise
• Underwear, lingerie, socks, and hosiery worn in direct contact with the skin
• Baby garments and children's clothing, which are subject to stricter color fastness requirements in many markets
• Medical and hygiene textiles, including bandages, orthopedic supports, and reusable protective garments
• Workwear and personal protective equipment exposed to demanding wear conditions
• Compliance verification for eco-labels, product certification schemes such as OEKO-TEX, and retailer technical manuals
• Quality control during dye and auxiliaries selection, production monitoring, and failure analysis of customer complaints

Equivalent and related national standards include AATCC 15 in North America, JIS L 0848 in Japan, and GB/T 3922 in China, so manufacturers exporting globally should confirm which method each buyer specifies, since procedural differences can produce different ratings.

FAQ

What is the difference between ISO 105-E04 and AATCC 15?

Both methods evaluate perspiration fastness, but ISO 105-E04 uses both acid and alkaline solutions at pH 5.5 and pH 8.0, exposes specimens for 4 hours at 37 °C, while AATCC 15 uses a single acidic solution at pH 4.3, incubates for 6 hours at 38 °C, and uses its own staining scales and apparatus. Results are similar in principle but not directly interchangeable.

What rating is considered a pass?

Acceptance limits depend on the buyer and product standard, but typical commercial requirements call for a minimum grade 4 for color change and grade 3 to 4 for staining in direct skin contact articles. Certification schemes and children's products generally demand the higher end of this range.

Why are both acid and alkaline perspiration tests required?

Human sweat shifts from acidic to alkaline depending on the individual, body location, diet, and activity level, and some dyes are sensitive to only one pH range. Testing both conditions provides a realistic picture of real-world performance.

What equipment is needed to perform the test?

The essential equipment includes a perspirometer with calibrated loading weights, a laboratory oven capable of 37 °C ± 2 °C, analytical glassware and a pH meter for solution preparation, multifibre or single-fibre adjacent fabrics, and grey scales conforming to ISO 105-A02 and ISO 105-A03, supported by a standardized lighting and viewing environment for assessment.

How long does the complete test take?

The core procedure from wetting to drying typically takes one working day, with an additional day often required for specimen conditioning, grey scale evaluation, and reporting in a third-party laboratory workflow.