Re: Exposure (was: Rangefinder etc)

[v.bromfield@xxxxxxxxxx (Vaughan Bromfield)]

At 11:02 AM 18/7/96, Willem-Jan Markerink wrote:

>In the past several people have emailed me asking for the proper
>setting for the darker colors 87B and 87A. Regrettably, Kodak has
>skipped many of its IR colors (only 87 & 87C remaining I believe),
>so I am currently involved in a (too) long project having this color
>made in resin.

To be honest I have always use Hoya filters and have never bothered
learning the Wratten designations. So I know what a R25, K2 and O(G) filter
is as well as 81a, 82a, but 87x I dunno.

I have the Hoya opaque IR filters, and my understanding is that they are
still readily available. The actual designations I cannot remember,
something like IR650 or similar designating the visible-light cut-off point
-- one cuts-off deeper (ie transmits less far-red light) than the other. I
have the "shallower" one, and if you hold it to a light you can see a deep
dark red image through it, so I guess it has similar transmission
characteristics to a bottle of Port!

So perhaps much time and effort may be saved looking into the Hoya range of
filters. Unless, of course, the *challenge* of diy IR filters is your thing
;-)

Vaughan

----------------------------------------------------------------
| Vaughan Bromfield                  |                         |
| ITD Education Consultant           |                         |
| University of Technology, Sydney   |  Phone: +61 2 9514 2176 |
| P.O. Box 123                       |  Fax:   +61 2 9514 1169 |
| Broadway  2007   (Australia)       |  V.Bromfield@xxxxxxxxxx |
|====================================|=========================|