Manufacturers Colourcraft (colours and adhesives) Ltd. describe them as: A unique, transparent, highly pigmented water-colour ink powders giving wonderful bursts of colour when used, exclusively manufactured by us at our factory in Sheffield. Brusho® crystal colour offers a very good degree of light fastness. Inevitable I bought a set of the paints (what not more paint) as the colours are great, but I can't pin down details about how much a 'good degree of lightfastness is' so I have painted them out to do my own light fading tests. Great colours which fade would lead to disappointment .