[pure-silver] Re: hp5+ at 125 development times
- From: Tim Daneliuk <tundra@xxxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Mon, 05 Oct 2009 12:32:53 -0500
Tim Daneliuk wrote:
> But ... Shannon exposed at ASA 125, almost a full stop more light than my
> nominal.
> (In zone system terms it's about N-1 - something you do when you need to
> contract
> the contrast range a bit when it's too long to fit on the film.) So further
> underdevelopment (from my nominal) would be indicated. It's hard to know how
> much, but I'd guess another 15% or so would be in order so:
>
> 11 * .65 = 7.15 min
>
Actually, this is wrong. To move the effective ASA down from a nominal
200 to 125 is more like N-3 exposure in ZS terms which - ballpark -
would be more like 50% below *nominal* development:
8.8 * 0.5 = 4.4 min
The problem here is that this assumes the negs were exposed with this
much contrast range contraction in mind ... which they were not in this case.
So ... we have to play a guessing game. If we develop too much, we get
blown out highlights. If we develop too little, the contrast range is going
to suck (assuming the images had a normal contrast range in the first place).
We have to split the difference between nominal and the 4.4min calculation
above. This will give us somewhat denser than usual shadows and somewhat
higher than usual highlights - both hopefully can be controlled using VC
paper and split printing later on. My best guess, therefore would be
a development time of about 6.5 min. If the subject of the negs had
a lot of real bright highlights like clouds or brightly illuminated
surfaces (building walls, windows, running water), I'd also consider only
agitating (you usual way/frequency) the first 5 minutes or so. When you
stop agitating, the developer around the highlights exhausts and stops
working on those areas while the shadows continue to develop.
Again - this is all guessing by the seat of my pants. If you can provide
more information about the nature of your subject, it may be possible to
refine the recommendation a bit more ...
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Tim Daneliuk tundra@xxxxxxxxxxxxxx
PGP Key: http://www.tundraware.com/PGP/
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