whilst dye molecules may gain uniform access to all interior fibre surfaces in a hydroentangled nonwoven structure, only the outermost fibres within a yarn-based structure might be readily accessible. This was supported by the calculated porosity values for each undyed fabric type which followed the order: nonwoven > knitted > woven for both cotton and PET fabrics, which fitted well with the colour strength order: nonwoven > knitted > woven.