ISO 10545-16:2010

Overview

ISO 10545-16:2010 - Ceramic tiles - Part 16: Determination of small colour differences - specifies a laboratory method to quantify small colour differences between plain-coloured ceramic tiles intended to be uniform. The standard uses instrumental colour measurement (spectrophotometers or trichromatic colorimeters) and the CMC colour-difference formula to produce an objective ∆Ecmc value. This allows manufacturers, testing laboratories and specifiers to set a maximum acceptable tolerance for colour conformity that depends only on closeness of match, not on the visual nature of the difference.

Key topics and technical requirements

• Measurement method: Use a reflectance spectrophotometer or trichrome colorimeter; geometries permitted are 45/0, 0/45, d/0 or 0/d. For diffuse geometries the specular component must be included.
• Reference conditions: Use illuminant D65 and 10° observer for CIELAB calculations (L*, a*, b*, C*, h).
• Colour-difference metric: Calculate CMC colour difference ∆Ecmc (l:c) per ISO 105-J03:2009 (calculations and component conversions), and decide an l:c ratio (e.g., 1.5:1 often used for high-gloss glazed tiles).
• Commercial factor (cf): A tolerance value agreed between parties; ∆Ecmc is compared to cf to accept or reject batches. (Note: ISO indicates anticipated commercial factors in ISO 13006 when revised.)
• Sampling and measurement protocol:
  • Reference sample: at least five tiles from the same pigment mix (to avoid metamerism).
  • Test sample: representative random selection - never fewer than five tiles.
  • Clean tile surfaces with laboratory-grade isopropanol, dry with a non‑fluorescent absorbent cloth.
  • Take three measurements per tile, alternate reference and test tiles, and average the three readings for calculations.
• Reporting: Include instrument details, ∆L*, ∆C*, ∆H*, agreed cf, mean ∆Ecmc and l:c ratio.

Applications and who uses it

• Quality control in ceramic tile manufacturing (production conformity, batch acceptance).
• Independent testing laboratories performing tile conformity tests for suppliers and clients.
• Architects, specifiers and purchasers who need objective criteria for colour matching between tile batches.
• Construction and tiling contractors verifying delivered tiles before installation. Practical value: objective, repeatable colour control, reduced disputes, and traceable acceptance criteria.

Related standards

• ISO 105-J03:2009 (calculation of colour differences)
• CIE 015:2004 (Colorimetry)
• ISO 11664-4/CIE S 014 (CIELAB space)
• ISO 13006 (ceramic tile definitions/classification - commercial factors reference)
• ISO 23603/CIE S 012 (spectral quality of daylight simulators)

Keywords: ISO 10545-16:2010, ceramic tiles, colour differences, ∆Ecmc, CMC, spectrophotometer, colorimeter, CIELAB, D65, quality control.