On 8 Jan 98 at 15:19, Peter Leyssens wrote:
> Wow, what a lot of reactions on one day. Seems I've touched a few
> people's hobby here.
> Summarizing :
> 1) Shawn : the web page link for pushing HP5+ up to 3200 : I've seen
> this one, but since I only have Rodinal at the moment, I only checked
> that part of the table (which goes up to 1600). It *is* very
> interesting, but I was kind of looking for 'general push experiment
> guidelines' or maybe a few curves like the contrast- and the
> temperature-development time curves. BTW : for T-Max3200, the list goes
> up to 25000 ASA ! That's nice for a start :-)
> 2) Lars : I've got a place (my kitchen which is a narrow U-shape) that I
> can use as a controlled scene. I knew the contrast would go up, but I
> didn't know why. I didn't know about the chromium intensifier. Sounds
> interesting. Thanks for the lesson !
> 3) Gene : on one side, I'd like to stick with Rodinal because I'm using
> this already for my evening classes in photography (where we calibrate
> our development process). On the other hand, now I'm deviating anyway
> ...
>
> I think I'll be starting with my regular Rodinal, using the 50%
> time/stop and see what the result is. Unfortunately, evaluating on
> prints is a bit harder for me because I don't have an enlarger (and
> doing it during the hours of the evening class isn't always possible, of
> course). I'll buy myself a good enlarging lens for studying the
> negatives and if that doesn't work, I'll have to do the printing anyway.
>
> What the purpose of all this is ? Well, just experimenting. If the
> effect is graphically nice, that's fine. If I can just shoot pictures
> of the Pleiads with my 300mm/f5.6 without a tripod, that would be nice
> too (astrophoto pun : that's a few minutes exposure normally).
>
Since I got Ansel Adams "The Camera" and "The Negative" for Christmas (now in
paperback), I'm freshly hyped on zones & such...
What you might want to try is using a spot meter (a 2S or OM-4/T, or a
handheld) to evaluate the densities since you don't have an enlarger (and
presumably a densitometer). I'd try some exposures at zones I, V and VIII to
start, at say ISO 3200, bracketing by 1stop, using the rough dev guideline.
Compare these densities with a test roll and "normal" exposure and development.
If you remember that Zone I should be 0.10 above film base+fog, (ie: 1/3 stop),
you should be able to determine the target ISO rating for a given
development time, then find the matching zone V and zone VIII exposure at the
same ISO and determine their densities. This will give you an idea of where the
contrast curve is going. At 3200, you may find that zone VIII is pushed too far
off the scale. If you're using a whole 24exp roll, you could try Zones
I,III,V,VI,VII,VIII,IX in 3 sets bracketed around the target ISO. If you able
to measure the negs accurately on a light table with spot meter, this will give
you a decent film curve. (Remember that each zone = 1 stop)
I was about 1/2 way through this process before sending my 4-T in for service,
so I can't verify whether the spot meter method actually works, but it should.
I was testing for normal development and film speed on FP4+, but the idea is
similar.
Good luck and let us know what happens.
========================
Shawn Wright
Computer Systems Manager
Shawnigan Lake School
250-743-6240
swright@xxxxxxxxx
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