Andrew Fildes wrote:
<<
>Alcohol for cleaning? - good on bodies but for glass - WINDEX repeat WINDEX
>on a Johnson and Johnson pure cotton bud. It works much better (and I used
>to use lab grade ethanol).
>>
Garth Wood <garth@xxxxxxxxxxxxxxx> replied:
<< (ammonia attacks metals quite nicely). This made me
hesitant to recommend it to anybody else, since it might do a really fine
job of attacking multicoatings. >>
What are the multi-coatings made of anyway? I guess that they could be the
same stuff that I used to see at Thorn Lighting in the UK on these little 12
volt display lamp reflectors. They used ZnS/MgF2 alternating layers, but
these were replaced by ZnS/SiO2 because they were much more moisture
resistant and environmentally resistant in general. SiO2/TiO2 were used by
some other manufacturers. This was in the early 90s. I know because we
sometimes used to buy these reflectors in and other times made our own in the
factory. I did a scanning electron microscope analysis of all these at
various times, but I wouldn't want to do it on a pristine Zuiko lens!
Sometimes I would get to look at these reflectors after they had spent 300
hours running hot in lamps in a high humidity chamber, and the state of these
under the microsope would make you pack some silica gel in with your lenses!
Dave Bellamy.
http://members.aol.com/synthchap/
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