Understanding the effects of lighting upon the appearance of fabrics.

Currently laundry formulations employ optical brighteners in order to make the fabrics washed in them appear a brighter and better balanced white. These work by absorbing UV light from either sunlight for artificial lighting, and re-emitting this absorbed energy by fluorescence in the blue portion of the spectrum, countering the yellowing or 'dingy' fabrics. An alternative way of bringing about this effect is to add a 'hueing dye' to the laundry, such as 'Reckitts Blue Bags. This older technology (mid 19th century) affects the perceived colour of a fabric by absorbing light in the red and green portions of the spectrum, restoring the white colour balance to the object, but making it less bright. Modern lighting technology is tending away from UV-generating fluorescent lighting, and towards the use of white LED technologies. These new light sources produce no UV radiation and hence will render the optical brighteners unless indoors.
This work will examine the fundamental absoroption, emission and scattering properties of fabrics and the agents that may be used to change their appearance under various lighting scenarios, with a view to improving the perceived colour of laundered clothing under a variety of lighting conditions.