Colours have variable waves length. From 380 nm of the violet to 760 nm of the red. Colours are sensations. Colours are a psychological event related to sight. When their radiations hit our eyes, our organism reacts in a un-rational and emotive way. Colours are universal but, emotionally talking, they are differently perceived. Cromica can interact with the environment - using sensors - or works in a standalone mode with different effects (e.g. warm, cold, random...)