From: Michael Healy (mjhealy@kcnet.com)
Date: 10/19/02-10:06:29 AM Z
Don, I've always assumed that compensation for reciprocity depended on the
film. Does the Sexton data account for this, or has he devised a generic
that applies to any film? Do you suppose you send a copy of your spreadsheet
to me as well?
Mike Healy
----- Original Message -----
From: "Don Bryant" <dsbryant@mindspring.com>
To: <alt-photo-process-l@skyway.usask.ca>
Sent: Saturday, October 19, 2002 6:38 AM
Subject: Re: reciprocity failure chart failure
> Shannon,
>
>
> > I can probably print these negatives with some care, but I
> > wonder if anybody has done any testing about reciprocity failure and
>
> Yes, use John Sexton's reciprocity data, it works very well.
>
> > how people estimate their long exposures. My exposures ranged from
> > about five seconds to ten minutes, in one case. Most of them were
> > about two to three minutes.
> >
>
> Those are extremely long exposures for daylight.
>
> If you have any HC-110 you could develop in dilution B which is then
diluted
> 1:49 for about 20 minutes @ 70F. Of course this is only a suggested
starting
> point, you may need to extend or shorten the development time a bit,
however
> this is a very dilute solution so be sure to use a sufficient volume of
> developer. 2 liters should work okay for a single sheet (this is for tray
> development, I don't know what volume you are using for drum). This method
> is recommended by Bruce Barnbaum and it works very well. Even with that
much
> compensation of development you may need to reduce the negatives with a
> negative reducing formula using ferricyanide. You will need to test and
see
> what works.
>
> > Kodak's chart says, for example, that if your metered time is 10
> > seconds, your actual time is 50 seconds, and to cut development by
> > 20%. I haven't been trimming the development time, but I plan to
> > start doing that for the next batch to see if that helps.
> >
>
> It sounds like your zone 3 exposures are going to end up on zone 5 (or
> higher). You should be able to save the negs but they may be a little
> grainy.
>
> If you don't have the Sexton reciprocity charts I can send you a copy off
> line as an Excel spread sheet or a formatted text file.
>
> Good luck,
>
> Don Bryant
>
> > --shannon
>
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