One of the first projects with which I was involved when I moved to Michigan in the early 70s was a water recycling system for the home. (Don’t worry- this had relevance to 3D printing, I promise!) We added a very powerful ultraviolet light (UV) light to disinfect the water. From that UV technology, the ability to “cure” ink on silver aluminum cans was derived. Which greatly increased the demand for – and technology around- UV curing.