Hi Richard:
You are right, the PQ7 has 16% to 16,5% hydroquinone, 8 to
8,5% sodium sulfite, 5% potassium bromide, 64 to 65% distilled water and 8
to 8,5% "others" according the data in the plastic bottle for the
concentrated solution, that "others" is for the "phenimek"/phenidone
according reliable data. You need to use it diluted 1 developer: 3 water,
it's the only dilution the manufacturer recommends. The working solution
could be used to develop 8 120 film or 8 35mmx36 frames or equivalent, you
need to increase 10% the developing time after the second film you
developed.
The data sheet for this developer says it has a basis of "phenimek", but it
does not appear in the bottle data, it must be "others" as I explained. I
have used Ilford Microphen several times, Microphen is a powder developer
and it has different developing times and can be used as a stock solution
or diluted with different results, PQ7 is 1+3 only.. Liked very much the
results I obtained with the PQ7 and Ilford 3200 film
This is the only data sheet available in the web for the PQ7, developing
times suggested for differents films are a good initial recommendation IMO
(there is a "+" sign at the end of the first page to enlarge the leterrs
size):
https://es.slideshare.net/hernan030/revelador-pq-7
Carlos
El mar, 15 dic 2020 a las 17:52, `Richard Knoppow (<dickburk@xxxxxxxxxxxxx>)
escribió:
I was unable to find any information on this on the web. The
manufacturer has a web site but it only displays various
developers. Its on the giant developer chart (drawing a blank on
its right name).
My guess is that the PQ means phenidone hydroquinone If so
that might make it similar to Ilford Microphen. Microphen is
similar to a phenidone version of D-76. I think Ilford has a
published formula for something similar but can't remember its
number off hand. Microphen is a good, general purpose, fine grain
developer which in comparison to D-76 delivers slightly finer
grain and slightly higher speed. I am a bit puzzled by the
dilution. For Romek its given as 1:3. So either its more
concentrated than Microphen or is a different developer. Ilford
does give instructions for Microphen diluted to 1:3. At that
dilution is becomes a high definition developer. Actually, D-76
does too. Kodak does not give times for 1:3 but Ilford does for
ID-11 which is identical. I've tried it and get a very strong
edge effect but don't like the way it looks.
AFAIK, the patents where they ever existed for all these
developers has long expired so anyone can make something like
Xtol, T-Max, Microphen, Microdol-X, etc, etc.
Several modern developers use Phenidone in place of Metol and
ascorbic acid in place of hydroquinone. Generally, Phenidone
yields slightly higher speed than the metol equivalent.
Back in the 1930s C.E.K. Meese, the founder of Kodak's
research lab, said that the great number of developers only
showed how many ways there were of doing the same thing.
Also, those of us in the U.S.A. have the advantage that we
can buy nearly anything even despite some EPA regulations where
in other countries there are import restrictions or other barriers.
On 12/15/2020 1:17 AM, CarlosMFreaza wrote:
Hello Louis:
Thank you. I like B&W very much, anyway I
also like to shoot color sometimes. Romek PQ7 is a developer
manufactured in my country, the factory info about this liquid
developer is basic; it's an ultrafine grain developer on the
basis of an element they call "phenimek", I guess phenidone, an
Ilford trade mark. I use it because I like the results most of
the time and it's available here regularly, at least so far; I
have used several other developers like Agfa Rodinal, D76, both
Tmax, Perceptol, Microphen, Tetenal Ultrafin Plus, I liked all
them, but some of them are not available here sometimes or they
become more expensive due to the exchange rate, therefor I'm
using the PQ7 from some time ago. There is some additional info
and feedback about the PQ7 from users, but most in Spanish.
I liked your photographs at Flickr, nice light and good contrast.
Carlos
--
Richard Knoppow
dickburk@xxxxxxxxxxxxx
WB6KBL
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