Re: rodinal developer for infrared

[George L Smyth <GLSmyth@xxxxxxx>]

Willem-Jan Markerink wrote:
> 
> You say you take a bare reading with your (handheld?) meter set to
> EI32, and compensate +2 stops for the #25 filter. That is an
> effective IE of 8.
> Your TTF reading suggest you set your meter to EI8, and *then* take a
> reading through the filter, adding at least another +2 to +3 stops
> (depending on the red sensitivity of the meter). So you end up with
> an EI of at least 2, perhaps 1.

Hmmm, it seemed clear to me. <g>  The first statement is true (although
I always meter TTF).  The second statement, however, doesn't ring true
to me.  If I shoot at the same speed as I metered, then the EI I shot at
would be the effective EI.  In the first instance the metered EI and
effective EI are different because of the filter.  In the second case
they're the same.  It would only drop to EI2 if after metering I placed
a second #25 filter on the lens and opened up two more stops.  Then the
effective EI would drop to 2.  Perhaps I'm missing something? (possible
- I've sent more than my share of messages today <g>)

george

-- 
 Handmade Photographic Images     
  http://www2.ari.net/glsmyth

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Topic No. 10