From: Manuel Gomes Teixeira (PunctumStudios@netc.pt)
Date: 09/02/01-06:26:26 PM Z
Hi Sandy,
Thanks for you and all others members for all the useful comments about BPF
in ABC+.
you wrote:
"If you are shooting in low contrast situations, however,
> you will not be able to approach this kind of DR without increasing
> the films b+f."
You're right , most of times I shoot immediately the sun has disappeared in
the horizon. That absolutely magic light !
"I rate BPF at an EI of 150"
As I said before I'm obsessed by shadow detail , perhaps I'm overexposing.
I have only one B&W densitometer so I'm unable to read my shadow density in
pyro negatives in order to confirm this. Visually ,my negatives have plenty
of density perhaps to much, but that doesn't explains the overall excessive
density (b+f or stain ?).
"Finally, what is your exposing light for POP ?"
Usually I use Bl tubes because my darkroom and working space has no
suitable place to expose the printing frame to sunlight.
Nevertheless I learned last week when I tried to expose some very dense
Ilford Ortho+ film with silver POP at direct Portuguese sun for several
hours that the film stick to the printing frame glass because the back of
the film literally melted !!
I confirmed that when I expose POP to a normal fluorescent tube for 12 to
24 hrs the contrast will increase visibly.
I do not confirm as you said that direct sunlight will be faster than
artificial light source. My experience says the opposite. At least with my
working conditions.
Thanks again for your support. Here in the west limit of Europe I feel
sometimes like a alternative Martian :-) .
Greetings
Manuel Gomes Teixeira
Punctum Studios
Portugal
EU
> From: Sandy King <sanking@clemson.edu>
> Reply-To: alt-photo-process-l@sask.usask.ca
> Date: Fri, 31 Aug 2001 18:41:49 -0400
> To: alt-photo-process-l@sask.usask.ca
> Subject: Re: POP choices
>
> Manuel Gomes Teixeira wrote:
>
>
>> I was
>> interested in obtaining negatives that could be printed in both contact
>> methods Pt/Pd, Silver POP and with conventional VC paper for enlargements.
>> Nevertheless I was intending to use other developers than Pyro but after
>> reading your post I'm quite pessimistic about it.
>
>
> In spite of its limitations it is still very possible to get enough
> contrast for POP printing with BPF. I can get a DR with this film in
> normal lighting conditions (SBR 7) of about 1.6-1.9 with either ABC+
> or Pyrocate-HD, which should be more than enough for most POP
> processes. If you are shooting in low contrast situations, however,
> you will not be able to approach this kind of DR without increasing
> the films b+f.
>
> BTW, if you are getting very high b+f with ABC+ something is wrong
> with the developer or film as this combination gives me negatives
> with a b+f of about 0.25, not real low but not unreasonably high
> either. You may be over-exposing..
> Remember, if you increase development times to get a high DR you
> should also increase the EI of the film somewhat as the extra time in
> development will give you an increase in effective film speed so if
> you are basing your exposure on a shadow density and developing for
> about 2X normal time I recommend you increase the EI of the film to
> about 250.
>
> Finally, what is your exposing light for POP. In spite of everything
> I still sometimes get negatives that are too dense for printing with
> my artificial light source (BL tubes). Try direct sun with this type
> of negative. I have some negatives that are so dense that they will
> not print with the BL tubes even with 4 hour exposures, yet they
> print beautifully in direct sun in 30-40 minutes. As a rule I find
> POP about three times as fast at my BL tubes for POP processes. That
> is, an exposure that takes 5 minutes with the sun will take 40
> minutes with the BL tubes.
>
> Sandy King
>
>
>
>
>
>
>
>
>
>
This archive was generated by hypermail 2b30 : 10/01/01-01:41:32 PM Z CST