Re: filmscanners: Re: looking at the Sun

[Arthur Entlich <artistic@ampsc.com>]

Shough, Dean wrote:

>> From a prctical point of view, I seriously doubt that glass absorbs a heck
>> of lot of UV, certainly not over a long term.
>> 
> 
> 
> Correct.  Most glass readily transmits near UV quite well.  For example, a
> very common optical glass, BK7 transmits 80% of light at 340 nm and 5% at
> 300 nm.  This is typical for many glasses.  It is mainly the heavy flints
> and rare earth glasses that tend to absorb the near UV.

Hi Dean,

I realize that your reference to optical glass is due to the discussion 
of camera lenses and the risk of looking through the viewfinder at the 
sun, but since this seems to be an area you have explored in some depth, 
would you know how regular window glass or picture frame glass do in the 
UV screening process?  Also, I imagine certain wavelengths of UV are 
more damaging to things like ink dyes than others, so does the 
"bandwidth" of wavelengths the glass screens make a big difference in 
things like inkjet prints fading?

Art