At 17:18 3/31/02, Walt Wayman wrote:
But the "pan" part means it was panchromatic, as opposed to
orthochromatic, which I doubt many of the younger folks here even know
there ever was any such a thing as.
Walt Wayman
Orthochromatic is why I ordered a B+W 470 filter late last week:
http://www.schneideroptics.com/filters/filters_for_still_photography/special/
Oddly, it's not listed under their Black/White filters, but under their
"special" ones. It uses Schott BG 18 glass and is classed as a
"blue-green" or "cyan." Its curve is very close to a "minus red" filer:
http://www.besoptics.com/html/schott_bg18_filter_glass.html
The B+W 470 is about as close as one can get to the color response of the
orthochromatics when using the panchromatics with a practical screw-on
filter for field use.
None of the above information should be construed as providing *any*
indication about my age. Rumors that I'm the person who suggested to
Theodore Roosevelt that he head up the hill instead of down it are merely
Urban Legend!
-- John
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