This method is intended for determining the resistance of the colour of textiles of all kinds and in all forms to the action of bleaching baths containing sodium, calcium or lithium hypochlorite in concentrations normally used in commercial bleaching. It is applicable mainly to natural and regenerated cellulose materials.
A specimen of the textile is agitated in a solution of sodium or lithium hypochlorite, rinsed in water, agitated in a hydrogen peroxide solution or sodium bisulphite solution, rinsed and dried. The change in colour is assessed with the grey scale.
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