Mohanad Aldib

A new method for evaluating the light fastness of photochromic fabrics was established, aimed at replacing the conventional method with an instrumental method. This method was based on comparing the colour difference of photochromic fabrics after light exposure with measured values of the colour differences of the blue wool references after fixed periods of light exposure. This method benefits from replacing the traditional visual evaluation of colour difference between exposed and unexposed areas of textile samples with a more accurate, instrument‐based measurement of the colour difference. The light fastness is then evaluated by comparing the colour difference with tabulated values of colour differences brought about by light exposure, for increased periods of time, of standard blue wool references. This method could be used for measuring light fastness of both traditional and photochromic fabrics. However, blue wool references and tested samples should be exposed to light under similar conditions when using this method to measure colour fastness to light of fabrics.

The application of a series of commercial photochromic dyes to polyester fabric by a digital inkjet printing method was investigated. Solvent‐based ink systems using the dyes were formulated. The inks were characterised in terms of their physical properties which are related to the jettability of the inks, and finally the prints were fixed onto polyester fabrics by thermal fixation. Colour measurement of the printed fabrics was used to measure their degree of photocoloration, fading rate, fatigue resistance, and storage stabilities. The measured properties of the inkjet‐printed fabrics were compared with the same properties of the same dyes applied to polyester fabrics by dyeing methods. The printed fabrics demonstrated inferior performance in terms of the degree of photocoloration, superior performance in the case of background colours, a higher rate of fading, and a lower fatigue resistance compared with that shown by the same dyes applied to polyester fabric by dyeing methods.