Overview
EN ISO 105-E05:2010 - Textiles - Tests for colour fastness - Part E05: Colour fastness to spotting: Acid (ISO 105‑E05:2010) is a CEN-endorsed ISO method for assessing how textile colours resist the action of dilute organic and mineral acids. The standard defines up to four severity levels of acid-spotting tests and specifies specimen preparation, reagents, test procedure and reporting. It applies to textiles of all kinds and in all forms.
Key topics and technical requirements
- Scope: Determines resistance of textile colour to dilute solutions of acids (organic and mineral).
- Test principle: Drops of acid solution are applied to a specimen and gently worked in with a glass rod; colour change is assessed while wet (optionally after 10 minutes) and after drying.
- Specimen sizes:
- Fabric: 40 mm × 100 mm
- Yarn: knitted into fabric of 40 mm × 100 mm or a wick of parallel lengths 100 mm long (~5 mm diameter)
- Loose fibre: compressed sheet 40 mm × 100 mm
- Reagents (examples provided by the standard):
- Acetic acid solution (300 g/L) - pH 1.8 to 2.4
- Hydrochloric acid solution (350 g/L) - pH 0.1 to 0.3
- Sulfuric acid solution (50 g/L conc. H2SO4) - pH 0.6 to 0.8
- Tartaric acid solution (100 g/L) - pH 1.5 to 1.8 (recommended for acetate fibres)
- Assessment methods:
- Visual assessment using the ISO grey scale (ISO 105‑A02)
- Instrumental assessment using spectrophotometer or colorimeter (ISO 105‑A05)
- Test steps: spotting, rubbing with glass rod, assess wet and dry change, allow drying at room temperature, repeat for each acid. For water effects, perform ISO 105‑E07 (colour fastness to spotting: water) as recommended.
- Reporting: Must reference ISO 105‑E05:2010, date, sample ID, grey scale or instrumental ratings (wet and dry), water-spotting result (if done), and any deviations.
Applications
- Quality control and acceptance testing of dyed textiles and finished garments
- Evaluating dye stability to accidental acid spills or acidic environments during processing
- R&D when selecting dye-fibre systems and finishes with improved acid resistance
- Certification and supplier verification for textiles destined for markets with CEN/ISO conformity requirements
Who uses this standard
- Textile manufacturers and dyers
- Independent testing laboratories and QC departments
- Product designers and textile engineers
- Procurement/specification teams and regulators
Related standards
- ISO 105‑A01 - General principles of testing
- ISO 105‑A02 - Grey scale for assessing change in colour
- ISO 105‑A05 - Instrumental assessment (spectrophotometry/colorimetry)
- ISO 105‑E07 - Colour fastness to spotting: Water
Keywords: colour fastness, textiles testing, ISO 105‑E05, acid spotting, grey scale, spectrophotometer, textile quality control, CEN.