perceptol formula?

"Larry" wrote in message
...
Does anyone out there have the perceptol formula? If you
do, could
you send to my e-mail. thanks....

Larry


The formula for Perceptol is proprietary. Perceptol is
evidently very similar, if not identical, to Kodak
Microdol-X. I have somewhere a patent which I believe is for
Microdol but will have to search for it. Both are low pH
developers which rely on sodium chloride (common table salt)
as the fine grain agent. Microdol-X evidently contains a
silver sequestering agent to prevent dichroic fog, otherwise
a problem for this type of developer. Its very likely
Perceptol has the same thing. My experience with Perceptol
is that it produces very clean negatives. If I can find my
guess at the Microdol formula I will post it but both of
these developers are similar to Kodak D-23 with about 25
grams of sodium chloride added.
I have no idea of what the sequestering agent is,
possibly a mercaptan but Kodak has many patents for
anti-silvering agents an any one of them could be the X in
Microdol-X.


--
---
Richard Knoppow
Los Angeles, CA, USA

Originally Posted by Richard Knoppow

I have somewhere a patent which I believe is for Microdol but will have to search for it.


--
---
Richard Knoppow
Los Angeles, CA, USA

What is the patent number?
I have seen some Kodak patents for fine-grain developers containing sodium and ammonium chloride and a couple of patents for anti-stain agents that reduce or eliminate dichroic fog.

Edgar Hyman`s Microdol substitute is 5 grams of Metol, 100 grams of sodium sulphite, anhydrous and 30 grams of sodium chloride per litre of stock solution although I don`t know how close that is to Kodak`s Microdol-X or Ilford`s Perceptol or the exact additives to the commercially sold products.

"Keith Tapscott."
wrote in message
...

Edgar Hyman`s Microdol substitute is 5 grams of Metol, 100
grams of
sodium sulphite, anhydrous and 30 grams of sodium chloride
per litre of
stock solution although I don`t know how close that is to
Kodak`s
Microdol-X or Ilford`s Perceptol or the exact additives to
the
commercially sold products.




--
Keith Tapscott.

One patent covering the Microdol type developer is:
USP 2466423 issued to John I. Crabtree and Richard Henn and
assigned to Kodak. The patent has some discussion of the
problem of silver fog in fine grain developers and suggests
some compounds for suppressing it. There are sample formulas
for both liquid concentrate and powdered developers. The
simplest is copied below but I suggest reading the patent
for a greater understanding of what the inventors were
trying to do.

Microdol _type_ developer

Water to make 1 liter
Metol 5.0 grams
Sodium sulfite, anhydrous 100.0 grams
Ethylene diamine sulfate 12.0 grams
Sodium metaborate 4.0 grams
Potassium bromide 0.25 grams
Sodium chloride 20.0 grams

The patent is dated 1945 so its about right for the
original Microdol. The X version was released a couple of
years later. Presumably the X indicates an improvment,
probably in the form of a better silver sequestering agent.
Kodak holds many patents on various sequestering agents,
only a couple are mentioned in the above patent.


--
---
Richard Knoppow
Los Angeles, CA, USA

Originally Posted by Richard Knoppow

One patent covering the Microdol type developer is:
USP 2466423 issued to John I. Crabtree and Richard Henn and
assigned to Kodak. The patent has some discussion of the
problem of silver fog in fine grain developers and suggests
some compounds for suppressing it. There are sample formulas
for both liquid concentrate and powdered developers. The
simplest is copied below but I suggest reading the patent
for a greater understanding of what the inventors were
trying to do.

Microdol _type_ developer

Water to make 1 liter
Metol 5.0 grams
Sodium sulfite, anhydrous 100.0 grams
Ethylene diamine sulfate 12.0 grams
Sodium metaborate 4.0 grams
Potassium bromide 0.25 grams
Sodium chloride 20.0 grams

The patent is dated 1945 so its about right for the
original Microdol. The X version was released a couple of
years later. Presumably the X indicates an improvment,
probably in the form of a better silver sequestering agent.
Kodak holds many patents on various sequestering agents,
only a couple are mentioned in the above patent.


--
---
Richard Knoppow
Los Angeles, CA, USA

There are some other similar patents for fine-grain developers including that one.
http://www.google.com/patents

Another one here describes the use of antistain agents, although I am told that these have long been superceded.
http://www.google.com/patents?id=vHF...ain+Developers

"Keith Tapscott."
wrote in message
...

Richard Knoppow;744145 Wrote:

One patent covering the Microdol type developer is:
USP 2466423 issued to John I. Crabtree and Richard Henn
and
assigned to Kodak. The patent has some discussion of the
problem of silver fog in fine grain developers and
suggests
some compounds for suppressing it. There are sample
formulas
for both liquid concentrate and powdered developers. The
simplest is copied below but I suggest reading the patent
for a greater understanding of what the inventors were
trying to do.

Microdol _type_ developer

Water to make 1 liter
Metol 5.0 grams
Sodium sulfite, anhydrous 100.0 grams
Ethylene diamine sulfate 12.0 grams
Sodium metaborate 4.0 grams
Potassium bromide 0.25 grams
Sodium chloride 20.0 grams

The patent is dated 1945 so its about right for the
original Microdol. The X version was released a couple of
years later. Presumably the X indicates an improvment,
probably in the form of a better silver sequestering
agent.
Kodak holds many patents on various sequestering agents,
only a couple are mentioned in the above patent.


--
---
Richard Knoppow
Los Angeles, CA, USA
There are some other similar
patents for fine-grain developers
including that one.
http://www.google.com/patents




--
Keith Tapscott.

Thats where I found it, probably doing a name search for
Richard Henn. Google Patents is an excellent research tool
since you can do complete text searches on any U.S. patent
ever issued and all are available directly as PDFs. The U.S.
Patent Office site allows text searches only for patents
issued from 1976 and all patents are downloaded as
page-by-pate FAX Tiff files. Its easy enough to convert them
to a single PDF but Google does it for you. Each patent will
give you some clue as to other searches. Its never ending
and a very great time sink.


--
---
Richard Knoppow
Los Angeles, CA, USA

Richard Knoppow wrote:
Thats where I found it, probably doing a name search for
Richard Henn. Google Patents is an excellent research tool
since you can do complete text searches on any U.S. patent
ever issued and all are available directly as PDFs.


Before Google Patents and the USPTO web site, IBM had an on-line
patent search web site. If you read the fine print, they told you that
they data-mined the queries. They had a group of people reading the
results of the data mining and the best ideas were presented to IBM
managment for evaulation and possible development as IBM products.

Since Google data-mines everything they "give" you, I would be very
careful about what I search there. I'm not saying they will take your
ideas, but who knows. It may also be construed as publication in a
court of law.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

"Geoffrey S. Mendelson" wrote in message
...
Richard Knoppow wrote:
Thats where I found it, probably doing a name search
for
Richard Henn. Google Patents is an excellent research
tool
since you can do complete text searches on any U.S.
patent
ever issued and all are available directly as PDFs.


Before Google Patents and the USPTO web site, IBM had an
on-line
patent search web site. If you read the fine print, they
told you that
they data-mined the queries. They had a group of people
reading the
results of the data mining and the best ideas were
presented to IBM
managment for evaulation and possible development as IBM
products.

Since Google data-mines everything they "give" you, I
would be very
careful about what I search there. I'm not saying they
will take your
ideas, but who knows. It may also be construed as
publication in a
court of law.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel
N3OWJ/4X1GM

Well, first of all I am searching to satisfy my
curiousity. Secondly, most of the patents I look at are very
old, long expired, and not useful for anyone trying to guess
what new, novel, and useful things I am inventing. I doubt
if anyone doing serious patent searches for the purpose of,
say, finding out if something is prior art, would use Google
and one can not use the USPTO site for that except for a
fee: the free searching has a limit.


--
---
Richard Knoppow
Los Angeles, CA, USA

WB6KBL

They had a group of people reading the
results of the data mining and the best ideas were presented to IBM
managment for evaulation and possible development as IBM products.

That doesn't happen. IBM is full of people promoting
their _own_ ideas, no one there is about to promote
someone else's.

Inspiration is worthless, it's the
perspiration that is worth something.

--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation: F-Stop Timers, Enlarging Meters
http://www.darkroomautomation.com/index2.htm
n o lindan at ix dot netcom dot com