These pigments normally have a pale, off-white appearance but in sunlight or UV light they change to a bright, vivid colour. The pigments revert to their pale colour when away from sunlight or UV light. If the pigment is mixed with a binder, such as an acrylic base, it can be permanently applied to almost any surface. The more dilute the pigment, the less dramatic the colour change. The mixing proportions are a matter of trial and error, but a 50:50 mix is a good starting point. The practical applications of the pigment are almost limitless.

The active photochromic dye is contained in micron-size microcapsules dispersed in water to make up the pigment, which has the consistency of thick cream.

• Uses range from UV warning systems to 'smart graphics' in publications and packaging and garment design.
• Methods of application include brush painting, block printing, stencilling, screen printing etc.

3g supplied in a plastic syringe.