Perceptol Recipe?
Steven Tackett
I have a complete stock of dry chemicals that I can mix my own developers
but I am short on actual recipes.
Please help!
John
Both are proprietary formulas which are not available to the public domain at this time. Microphen is probably _very_ similar to ID-68 which was Iford's published PQ film developer. Perceptol seems to be very similar to Microdol-X
The following is from my site at ;
http://www.darkroompro.com/html/darkroom/darkroom.html
Ilfords ID-68
Water 750 ml
Sod. Sulfite 85 g
Hydroquinone 5 g
Borax 7 g
Boric Acid 2 g
Pot. Bromide 1 g
Phenidone 0.13 g
Water to make 1.0 liter
This formula is probably the ancestor to Microphen. I'd imagine that Microphen has more Phenidone and slightly different amounts of alkali and will develop slightly better film speed but all in all they should perform very similarly. Dilute this developer 1:1 for good quality, fine grain and a high degree of sharpness.
***
Also note that Michael Gudzinowicz posted on the likely composition of Microdol-X in <5vgaks$l...@freenet-news.carleton.ca> and stated the following :
"The Kodak MSDS and product package provides some information on the
current composition of Microdol-X. The MSDS gives percentage ranges for
the constituents, and the conversion to grams per liter assumes that the
1 gallon packet of Microdol-X contains 17.0 oz powder. Reversing the
estimate using know formulas for a buffered version of D-76 can validate
the approach (I've done so; data not shown).
Percentage g/l
Sodium Sulfite 70 to 80% 93 to 106 g/l
Sodium Chloride 20 to 30% 26 to 40 g/l
Metol 1 to 5% 1.3 to 6.6 g/l
Boric Anhydride - -
Sodium Hexametaphosphate - -
A reasonable starting point for experimentation would be:
Sodium Sulfite 100 g/l
Sodium Chloride 33 g/l
Metol 5 g/l
Boric Anhydride 1+ g/l
Sodium Hexametaphosphate 1 g/l
Table salt should not be used due to other halides which have a marked
effect on film speed. Use a commercial packet of Microdol-X as a
control, and add boric anhydride to acidify the clone until activities
match, checking the CI with a densitometer. BTW, develop at 75F. Note
that packaged Microdol-X and other developers are often less expensive
that the cost of photograde chemicals used to mix developers.
You can probably replenish the developer with DK-25R in a manner similar
to D-23 replenishment."
Regards,
John S. Douglas
http://www.darkroompro.com
Richard Knoppow
"Steven Tackett" <steven_...@hotmail.com> wrote in
message news:uon911c...@corp.supernews.com...
Until recently both seem to have been virtually identical.
Recent MSDS for Perceptol indicate a change in formula,
although it may be an error in the current MSDS.
Microdol-X and the older form of Perceptol employ sodium
chloride (table salt) as a restraining agent. While the use
of sodium chloride as a fine grain agent has been known of
for decades it has not been employed in many formulas. It
appears from the MSDS that something close to Microdol-X can
be gotten by adding about 30 grams/liter to D-23.
Originally, this developer was sold as plain Microdol. The X
was added some years later indicating some change. This is
likely to have been an agent for preventing dichroic fog,
perhaps a mercaptan. Whatever it is the amount is so small
it doesn't have to be listed in the MSDS.
Currently, the MSDS for Perceptol shows it to contain a
large amount of sodium bromide. Bromide is a well known
restrainer and anti-fog agent. It can also be a fine grain
agent in the right developer. Assuming the MSDS to be
correct, the amount of bromide is somewhere around 20% to
33% of the amount of sulfite, about the same as the
percentage of sodium chloride used in the previous formula.
Perceptol also contains a small amount of sodium
polyphosphate, a sequestering agent. This is probably not
for the dissolved silver but for dealing with hard water.
Dichroic fog is a fine deposit of metallic silver
deposited on ether side of the film but mostly on the image
side. The name comes from the fact that it is one color by
reflection, usually pinkish, and anoter color by
transmission, typically yellow or brown. Extremely finely
devided silver (colloidal silver) is bright yellow by
transmission. In fact, the yellow color filter layer in some
color films (Kodachrome for example) are formed of colloidal
silver and are removed when the silver image is bleached out
and removed.
The fog in developers of the Microdol type come from the
silver halide dissolved by the sulfite. This very fine
halide is developed into metallic silver by the developer
and deposited on the film. All high solvent developers
suffer from dichroic fog to some extent, even D-76 can
produce it under some circumstances. The fine grain
properties of Microdol-X, Perceptol, Kodak D-25, Kodak D-76,
and many others, come largly from the solvent action of the
sulfite. This is not "eating away" of the silver particles
as often described, but rather dissolving of part of the
surface of the undeveloped silver halide. When only a small
amount of halide is dissolved, as in D-76, the film speed is
increased because more development centers are made
available to the developer. For developers with more solvent
action the speed is reduced because enough halide is
dissolved to remove some of the development centers, which
constitute the latent image.
Microdol-X, Perceptol, and D-25 all work by slowing down
the development process so that the solvent action of the
sulfite has longer to work. The sulfite also promotes the
production of silver filiments from the halide particles
rater than sharp-edged crystals. These filiments give the
silver grains something of the appearance of little tufts of
steel wool. They have greater covering power than halide
devloped into crystals the same shape as the original shape
of the halide so less light gets between them, hense the
finer grain. Note that these particles are microscopic, the
visible grain is due to conglomerations of silver grains,
singe grains are not visible except under a fairly powerful
microscope.
D-25 is an extra-fine-grain developer which retards the
development by being buffered to neutral pH. Metol will
develop in an acid or in a neutral solution, but its slow.
D-25 is comparable to Microdol-X or Perceptol in grain size.
It is the same as D-23 except for 15grams/liter of sodium
bisulfite to buffer the sulfite. I will append a couple of
formulas below.
A few older developers relied on additional solvents for
fine grain. Kodak DK-20 is among these. It is an M-H
developer containing sodium thiocyanate, a powerful solvent.
DK-20 was designed for old style thick emulsion films and is
unsuitable for modern films It will generate dichroic fog
and has no virtue over othe formulae. Some developers
employed developing agents which have solvent action. Mostly
these were para phenylenediamine and ortho phenylenediamine.
The ortho form is a weak developer but a good solvent and
was used by Hans Windisch and others in combination with
Metol to make fine grain developers.
This is all to the point that you can probably get what
you want with D-25, which is below.
Kodak D-23
Water (125F or 52C) 750.0 ml
Metol 7.5 ml
sodium Sulfite, dessicated 100.0 grams
Water to make 1.0 liter
Times and results are similar to D-76
Modified with a buffer this becomes:
Kodak D-25
Water (at 125F or 52C) 750.0 ml
Metol 7.5 grams
Sodium Sulfite, dessicated 100.0 grams
Sodium Bisulfite 15.0 grams
Water to make 1.0 grams
When used full strength about 3/4 stop of film speed is
lost. When used diluted 1:3 full film speed is obtained and
acutance effects take place, nowever the extra fine grain
property is lost and grain is about the same as D-23 or
D-76.
Times will be similar to Microdol-X.
Something close to Microdol-X will be obtained by mixing
D-23 and adding about 15 grams of Sodium Chloride. Do not
use table salt, its too likely to contain Iodide and other
impurities. Kosher or pickling salt is usually pure enough.
Since Metol will not dissolve in concentrated solutions of
sulfite the mixing instructions always direct that it be
dissolved first. It is important to purge dissolved oxygen
from the water to prevent rapid oxidation of the Metol. Two
suggestions on minimising the oxygen are, first; boil the
water for several minutes and let it stand and cool. Decant
it carefully to prevent aerating it again. Second, dissolve
about 15 grams/liter of Sulfite in the water before adding
the Metol. The sulfite will help to scaveng any remaining
oxygen. This is a very low concentration whcih will not
interfere with the solution of the Metol.
--
---
Richard Knoppow
Los Angeles, CA, USA
dick...@ix.netcom.com
Nick Zentena
>
> D-23 and adding about 15 grams of Sodium Chloride. Do not
Is there any guideline on subbing Sodium Chloride for other restrainers?
Nick
Richard Knoppow
"Nick Zentena" <zen...@hophead.dyndns.org> wrote in message
news:i7shma.07b.ln@barley...
not scientific ones. They often mislead about ingredients
and amounts as much as they tell you anything. The
percentage amounts listed in the Ilford MSDS for Perceptol
vary by a 2 to 1 ratio, not exactly helpful.
The MSDS for Microdol-X powder lists the ingredients as:
Concentrate:
70-75 Sodium sulfite (007757-83-7)
20-25 Sodium chloride (007647-14-5)
1-5 4-(methylamino)phenol sulfate (000055-55-0)
< 1 Boric anhydride (001303-86-2)
< 1 Sodium hexametaphosphate (010124-56-8)
The MSDS for the liquid concentrate lists:
Weight % - Component - (CAS Registry No.)
80-90 Water (007732-18-5)
5-10 Sodium sulfite (007757-83-7)
1-5 Sodium chloride (007647-14-5)
< 1 4-(methylamino)phenol sulfate (000055-55-0)
< 1 Sodium citrate (000068-04-2)
It would appear from this that a liter of Microdol-X has
something like 85 grams of Sulfite, perhaps 25 grams of
sodium chloride, 3 grams of Metol and small amounts of
sodium hexametaphosphate. The last is also known as Calgon,
a calcium sequestering agent. I am not sure what the Boric
anhydride is there for, perhaps some degree of buffering.
Sodium citrate may also function as a sequestering agent.
Probably both could be left out of a home made version.
Three grams of Metol is enough for development but not
enough for much of a capacity when used alone so the amount
may actually be toward the higher number, about 5
grams/liter.
Again, there is probably a silver sequestering agent
present in very small quantity. The silver sequestering
agent would prevent dichroic fog.
There is probably a patent on this stuff somewhere which
probably has close to the actual formula in it.
Steven Tackett
I will try your suggestions to the modifcations to D23 as you have listed to
see if it gives the results I have seen using Perceptol.
By the way, I really appreciate your exhaustive explanation of the
constituents of these types developers!
"Richard Knoppow" <dick...@ix.netcom.com> wrote in message
news:amhf32$88d$1...@slb3.atl.mindspring.net...
John
> I am not sure what the Boric
>anhydride is there for, perhaps some degree of buffering.
I think it's just the liquid version of Borax.
Richard Knoppow
"friend" <me.at...@universe.org> wrote in message
news:09sqou4lp6jhpaq6p...@4ax.com...
> On Sat, 21 Sep 2002 18:11:55 -0500, "Steven Tackett"
> <steven_...@hotmail.com> wrote:
>
> >Richard,
> >
> >I will try your suggestions to the modifcations to D23 as
you have listed to
> >see if it gives the results I have seen using Perceptol.
> >
> >By the way, I really appreciate your exhaustive
explanation of the
> >constituents of these types developers!
> >
> >
intentioned, but
> from chemist's point of view, too many misinformations.
> I do not recommend using MSDS as a source of info on
composition of
> photographic developers. Too long to explain.
> Sodium or potassium chlorides are good as restraining
agents
> (anti-fog) only for materials based on silver chloride,
ie. papers.
> Fimls use bromide/iodide mixture and chlorides are
ineffective. Why -
> apply Nernst's equation. Consider solubility product
constant and
> equilibrium with an excess of halide ions,as well. Bromide
ions
> released during developing will have bigger effect than
chlorides,
> unless you saturate developer with KCl or NaCl. For the
same reason
> iodides are much more powerful restrainers than bromides.
> Saying that, there are some reports on formulations
containing
> sulphite, metol and 30+ g/L of sodium chloride. In such a
case we deal
> with physical development, which may lead to very fine
grain indeed.
> So, chlorides serve different role, with quite good
results.
> Conclusion - Dick's explanation is not fully correct.
I don't think I said that sodium cloride is an
anti-foggant or restraining agent in the sense of Bromide.
It is a fine grain agent.
All of the developers which are slow acting and have
considerable sulfite in them have a significant amout of
solution physical development, including D-76. Those which
slow down development allowing the sulfite a longer time to
act, or which use a secondary halide solvent, have much more
solution physical development, although that is not the only
reason for finer grain.
The free silver in some of these developers can cause
significant dichroic fog.
I agree about using MSDS, as I pointed out they are legal
not scientific or technical documents. They are often meant
to disguise as much as expose the actual formula and
constituents of the materials they describe. However, they
can give you a clue as to what is going on.
John
> providing they are water soluble.
>you can treat boric anhydride as if boric acid less a molecule of
>water.
Thanks for the reminder.
Richard Knoppow
formula ID-68
Ilford ID-68 Fine Grain Phenidone-Hydroquinone-Borax
Developer
Water (at 125F or 52C) 750.0 ml
Sodium Sulfite, dessicated 85.0 grams
Hydroquinone 5.0 grams
Borax 7.0 grams
Boric Acid, crystaline 2.0 grams
Potassium Bromide 1.0 gram
Phenidone 0.13 grams