On Tue, 11 Nov 2003, Dr E D F Williams wrote: > The UV that passes clear glass (and gets through camera lenses) is rather > long wave -- just the other side of visible. Short-wave UV is stopped by > most glass. To pass short wave UV, optics made of quartz are needed.
Some month ago I learned that the limiting factor in us seeing UV light is in the lense of the eye rather than in the light sensitive tissue in the back of the eye. Some of the patients that have had their lenses replaced with synthetic lenses due to cataract/glaucoma (don't know which since I was told this in Swedish and those two conditions share the same word) actually can see a little bit into the UV range. For exemple, they can tell sugar and salt apart just by the colour. One was percieved redish and the other greenish, due to their different UV responses. anders ------------------------- http://anders.hultman.nu/
