Barry, Ken (kbarry@epri.com)
Wed, 14 Apr 1999 09:06:33 -0400
Thanks to everyone for their responses. I have broken out a ND filter to
get my f-stop up to a more sharp opening and I am ready to be more
systematic (base for shadows and flash for highlights - where have I seen
this before?) in determining base and flash times.
Liam stated:
> You say you used a 30-second base exposure (which, with the 3X factor,
> means
> your normal time would have been 10 seconds). Someone is borrowing my P-F
> at the moment, but I'm reasonably sure I said somewhere in the article
> that
> a flash time between 10 and 50 percent of the NORMAL time will usually
> cover
> the range of useful densities. For a normal exposure of 10 seconds, this
> would indicate a flash between 1 second and 5 seconds, which would give
> you
> a choice of maximum densities between 3.42 and (roughly) 0.8. (Sounds
> like
> you've confused the normal and base times, though without checking I can't
say whether I told you wrong in the article!)
I can honestly say that I read the article at least 20 times before starting
and a few times after. Every time I found things that I didn't see or
understand the previous time. So it is possible that I misread your
instructions. I will read it again tonight. But using Normal time to
calculate flash would put me in the right range. I have some good
negatives, I was just concerned that I was misunderstanding your procedure
and apparently I was.
> Well, you don't sound too disappointed with the method, though I'm sorry
you've wasted a whole box of film.
One of the advantages of Lith film is it is very cheap. And it was 25
sheets of 5x7 so it was real cheap. The box wasn't wasted; I am learning
and it was the first time I have mixed my own developers, etc., and the
Financial Coordinator let me buy an Ohaus triple beam balance. There is
nothing like doing, to push the learning curve along.
Thanks,
Ken Barry
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