BS EN ISO 8654:2018 pdf free.Jewellery – Colours of gold alloys – Definition, range of colours and designation [ISO 8654:2018). The samples to be measured shall have a flat and polished surface to be used as a measurement area. The measurement area shall be exempt of defect. The finishing (polishing and washing) shall be (re)done until a mirror surface is achieved (Y reaches a constant value). After polishing, the sample colour measurement shall be made within 120 mm maximum. NOTE Polishing, washing and environment conditions can greatly affect the colour. 5.2.1.2 Metallographic preparation Metallographic preparation is made with a final polishing with broadcloth charged with an abrasive solution. The solution contains 1 I.Im sized abrasive particles. 5.2.1.3 Sample cleaning The recommended sample cleaning is done by gently wiping the surface with a clean soft cloth (microflbre) and some isopropylalcohol (IPA). 5.2.2 Measurement apparatus 5.2.2.1 General The measurement apparatus for the colour measurement of a gold alloy shall be in accordance to CIE Publication No. 15. 5.2.2.2 Reference apparatus The reference apparatus for the colour measurement of a gold alloy is an integrating sphere spectrophotometer able to measure spectral reflectance, with a measurement geometry compatible with designation di:8° or 8°:di (specular…