PQ Stain

John Stockdale wrote:
I did read Patrick's item a few weeks ago with some skepticism, but
this really does sound interesting. I suppose I've been mixing with
water for so long that this concept seemed strange.

Since your negs look not very contrasty but print with greater than
expected contrast, I assume that they are stained like a pyro neg.
What is the colour of the neg image?
Brown and stained

Did you use VC paper?

No, Forte Fortezo G3
The reason for my asking is as follows: It used to be said the pyro
negs gave smooth prints because the stain added to the silver grain
(and gaps between grains), leading to good density with minimal
development which of course leads to minimal grain. This was with
graded papers. Nowadays with VC papers it is being said that pyro
gives a built-in soft filter to control highlights, but the effect is
not always desirable, since with VC paper the highlights can look flat
with some subjects.

I've heard that VC papers can do this as well, but also that the stain
(usually) increases the density of the neg more than the colour of the
stain decreases it even with VC...
Have you used PMK? If so, how would you compare PMK with this new
formulation?

No, I haven't tried PMK, Patrick just emailed me tonight privately
saying that he couldn't tell the difference between Catachol and
Hydroquinone in Pyrocat-HD and that it is a safer and cheaper what to
get what most people like about Pyro developers such as PMK. But perhaps
you should ask him exactly what he thinks instead of me paraphrasing him
as he has many years of experience with all of these developers.
Did you do a measurement of film speed?
No, but compared to the same roll I did in another developer this one
seems to have full speed without exaggerated FB+F.

I'm no chemist,
Me neither
but the formula of propyl glycol looks like an
alcohol. Does it absorb water from the atmosphere? I note that its
boiling point is 150degC, well above that of water and other common
alcohols. So heating it could drive off water as long as it didn't
decompose. The developing agents could also get cooked. How hot can
you make it before any such troubles occur?

Its a diol - a double alcohol. It doesn't seem to take on water because
if it did it wouldn't last as long as it does. Wonder why then one has
to heat it to expel the water as per Jorges comments on Patricks
recommendations?
Just what I wanted. Yet another developer to obsess over, just when I
thought I had narrowed it down to two.
Me too, I thought the same thing as soon as I developed these frames
last night. I was happy with my other developer, but compared to these
photos it looks like I've got a new favorite developer and it doesn't
have any Vitamin C in it at all!

Just a couple of general comments here on Patrick's most recent
developers to fill in some details about what Patrick, Nicholas and
Jorge have been writing about. Hope you guys don't mind me piping up
here to give a "bird's eye" description of this stuff.

Many of you know about Patrick's developers from the article posted on
the unblinkingeye.com web site. The ones he describes there are based on
combinations of ascorbic acid (Vitamin C) and phenidone or metol,
dissolved in various alkaline buffers (based on sodium carbonate or
borax/lye mixtures). None of his formulas use sodium sulfite, which
makes them very unusual in the developer world.

Patrick's latest film developers are also based on simple combinations
of developing agents and have also been formulated without any sodium
sulfite at all. However, lately he has been using propylene glycol as a
solvent (instead of water) to make up the stock solutions. The stock
solutions don't contain any alkaline component or preservative (other
than the Vitamin C itself). Part of the reasoning behind using propylene
glycol is that a water-free stock solution inhibits the ionization of
developing agents and reduces their tendency to be oxidized by air. The
stock solutions won't develop film until they are diluted in water
containing sodium carbonate, borax, or both. This is similar to the case
of HC-110, another stock solution in a viscous organic solution. Patrick
has found that HC-110 syrup (undiluted) does not develop film.

Although the propylene glycol has to be heated to get the developing
agents into solution, the developing agents don't crystallize out on
cooling. Propylene glycol is pretty readily available from chemical
suppliers, Photographer's Formulary, and also (pretty inexpensively) at
www.chemistrystore.com. It is non-toxic -- used as an environmentally
friendly antifreeze and as a base for cosmetic products, etc. It's a
viscous liquid and is quite hygroscopic (it absorbs water vapour from
the air). However, the amount of water absorbed isn't enough to cause
problems. The stock solutions in propylene glycol keep for a very long
time. The mixed developers give good film speed and fine grain. I've
used the Vitamin C / Phenidone version on HP5 Plus, FP4 Plus, and PanF
Plus with good results. The PanF looked especially nice.

What Nicholas and Patrick have been discussing here are variants of
these developers that contain hydroquinone. Patrick found that
hydroquinone acts a staining agent in the absence of sodium sulfite. I
don't know too much more about these experiments but they are very
promising. The fact that hydroquinone acts differently in this case than
it does in (say) D-76 isn't surprising. Hydroquinone is known to react
with sodium sulfite in alkaline solutions to form a sulfite addition
product.

Hope I'm not spewing incorrect info here, Patrick or Nicholas should
correct me if I am.

Jordan
(remove "pants" to reply)


John Stockdale wrote:

I did read Patrick's item a few weeks ago with some skepticism, but
this really does sound interesting. I suppose I've been mixing with
water for so long that this concept seemed strange.

Since your negs look not very contrasty but print with greater than
expected contrast, I assume that they are stained like a pyro neg.
What is the colour of the neg image?

Did you use VC paper?

The reason for my asking is as follows: It used to be said the pyro
negs gave smooth prints because the stain added to the silver grain
(and gaps between grains), leading to good density with minimal
development which of course leads to minimal grain. This was with
graded papers. Nowadays with VC papers it is being said that pyro
gives a built-in soft filter to control highlights, but the effect is
not always desirable, since with VC paper the highlights can look flat
with some subjects.

Have you used PMK? If so, how would you compare PMK with this new
formulation?

Did you do a measurement of film speed?

I'm no chemist, but the formula of propyl glycol looks like an
alcohol. Does it absorb water from the atmosphere? I note that its
boiling point is 150degC, well above that of water and other common
alcohols. So heating it could drive off water as long as it didn't
decompose. The developing agents could also get cooked. How hot can
you make it before any such troubles occur?

Just what I wanted. Yet another developer to obsess over, just when I
thought I had narrowed it down to two.

Jorge Omar wrote:

Patrick

I have easy access to 98%~99% pure ethanol (I believe it's not purified
through copper - CaO looks more like it if I remember right).

How would that compare to Pglicol in your opinion?

Besides, I would mix a stock alkali solution also.

Thanks,

Jorge

Patrick Gainer wrote in
:


Nicholas,

You may as well tell everyone what dilution and amounts of borax and
carbonate you used. I just got and signed the contract for the article
in Photo Techniques next issue, but I didn't describe the use of
borax-carbonate. Makes me feel good that you like the results.

We have been keeping the wrong thing away from developer in our
efforts to preserve stock solutions. We worry about air, when we
should be worrying about water. Keep the water away until the last
minute. Dissolve hydroquinone or ascorbic acid or catechol or
pyrogallol and/or phenidone in propylene glycol for the stock. I find
it necessary to heat the mixture in order to dissolve the dry
chemicals and to drive out water that may be in the glycol. This won't
work with most alcohols which would boil away before the water. There
is a method of dehydrating alcohol with anhydrous copper sulphate, but
who wants to take a chance on having traces of copper in the
developer?
When you use a technical grade of propylene glycol, there may be water
in it. When I first used heat to dissolve ascorbic acid, nothing much
happened until I got the temperature up near 250 F. At that point, the
ascorbic acid dissolved with evolution of steam. I was not sure whether
or not there was an actual reaction with the ascorbic acid, and am still
not.

Because the glycol does not ionize the developing agents as water does.
there is no noticeable loss of activity. Yes, glycols do take on water
from the atmosphere, but not very rapidly and only from the atmosphere
in the bottle, which cannot contain very much water. I did a life test
of a phenidone-ascorbic acid-glycol developer which will be described in
the upcoming article, which showed that after exposure to air of a thin
layer of stock solution 100 mm in diameter for 16 days, the stock
solution had lost no oomph. This is a rather extreme exposure. I don't
know of any stock solution of phenidone and ascorbic acid.

My interest was in sulfite-free developers. I have found that fine
grain, excellent sharpness and good film speed can be obtained without
any sulfite, and not just with ascorbic acid. Adding sulfite may
actually increase graininess without increasing acuity.

The staining-tanning developers include any that have two or more
hydroxyl groups such as catechol, hydroquinone and pyrogallol. The
staining is reduced by sulfite. Ordinarilly, sulfite is required for
preservation, but not when a glycol or alcohol or even an organic base
such as triethanolamine is used as a solvent for the stock solution.
After water is added, there is a rather short life, but long enough for
stand development if that is your cup of TEA. (Pun intended.)

"Patrick Gainer"

When you use a technical grade of propylene glycol, there may be water
in it. When I first used heat to dissolve ascorbic acid, nothing much
happened until I got the temperature up near 250 F. At that point, the
ascorbic acid dissolved with evolution of steam. I was not sure whether
or not there was an actual reaction with the ascorbic acid, and am still
not.

Ascorbic acid (vitamin C) is heat labile. I am not sure of the max temp
it will stand but do know that boiling water will destroy it.

I am afraid when it generated a puff, the acid went poof.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.

Nicholas O. Lindan wrote:

"Patrick Gainer"

When you use a technical grade of propylene glycol, there may be water
in it. When I first used heat to dissolve ascorbic acid, nothing much
happened until I got the temperature up near 250 F. At that point, the
ascorbic acid dissolved with evolution of steam. I was not sure whether
or not there was an actual reaction with the ascorbic acid, and am still
not.


Ascorbic acid (vitamin C) is heat labile. I am not sure of the max temp
it will stand but do know that boiling water will destroy it.

I am afraid when it generated a puff, the acid went poof.


My Merck Index gives a melting point of 190-192C for ascorbic acid with
"some decomposition". We may be losing a small part of the ascorbic acid
on dissolving it in the hot propylene glycol, but not much. The
developer still works just fine.

Aqueous solutions of ascorbic acid generally decompose quickly due to
aerial oxidation. Destruction of Vitamin C in boiling water is probably
just a heat-accelerated version of this. The vitamin C does not ionize
in propylene glycol and this probably protects it.

Jordan

I mixed my PA in Pglicol at some 80C (did not heath the Pglicol above that;
it's USP grade) 4 months ago.

It's working quite well - as a matter of fact, just developed a test strip
to test a recently repaired camera.

Jorge

Jordan Wosnick wrote in news:4031233e$0$573
:


My Merck Index gives a melting point of 190-192C for ascorbic acid with
"some decomposition". We may be losing a small part of the ascorbic acid
on dissolving it in the hot propylene glycol, but not much. The
developer still works just fine.

Aqueous solutions of ascorbic acid generally decompose quickly due to
aerial oxidation. Destruction of Vitamin C in boiling water is probably
just a heat-accelerated version of this. The vitamin C does not ionize
in propylene glycol and this probably protects it.

Jordan

Patrick Gainer wrote

My interest was in sulfite-free developers.

WAS? Why such exotic compounds such as brake fluid and antifreeze?
At bedrock is the lifespan of at least the stock or concentrate. Why
not some other scavenger of oxygen? Perhape an oxalate or even one
of those used in preserving pharmaceuticals in water solution. Dan

"Jordan Wosnick" wrote:
Nicholas O. Lindan wrote:
"Patrick Gainer" wrote:
dissolve ascorbic acid ... 250 F ... evolution of steam
Ascorbic acid (vitamin C) is heat labile. I am afraid
when it generated a puff, the acid went poof.

My Merck Index gives a melting point of 190-192C ... Destruction
of Vitamin C in boiling water is probably just a heat-accelerated
[oxidation]

Mea Culpa. I am reading the wrong cookbook; Fanny Farmer's
rather than Steve Anchell's.

Thanks: "Say something stupid -- learn something new."

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.

Dan Quinn wrote:

Patrick Gainer wrote

My interest was in sulfite-free developers.

WAS? Why such exotic compounds such as brake fluid and antifreeze?
At bedrock is the lifespan of at least the stock or concentrate. Why
not some other scavenger of oxygen? Perhape an oxalate or even one
of those used in preserving pharmaceuticals in water solution. Dan
Is there another one that is cheaper than glycol? Besides, glycols are
not scavengers of oxygen. In addition, oxygen is not the only concern.
Some developer solutions are unstable even when carefully protected from
oxygen. The mere ionization of molecules into parts that can oxidize and
parts that can reduce makes possible reactions that you may not want.

In order to get the sulfite-free preservation of stock solutions one
could use an alcohol, but it is difficult to keep alcohols from becoming
10% water. Pure alcohols are more expensive than glycol. Ethanol, for
most of us, is subject to a liquor tax. Besides all that, it makes more
interezting reading when I write about using antifreeze or brake fluid
in developers.

I just had an out of town, 'acquaintance / photographer / accomplished
printer', in my darkroom so I could develop a roll of film that he used to
test a camera he was thinking of buying... When I swung open the cupboard
doors and there stood cans of gas line antifreeze, Red Devil Lye, 20 Mule
Team Borax, Arm & Hammer Washing Soda, and Vitamin C powder, he started
mumbling, "No way... This is a joke, right? Where's the D-76?"...
Funny thing, after the negatives were hanging to dry and we were leaving he
was still mumbling, " . . & the goddam negatives look great.. I don't
believe this..."...

Sorta like the day he found the Santa Claus costume in dad's closet... I'm
not sure he will ever be the same...
denny

"Patrick Gainer" wrote in message Besides all that, it
makes more
interezting reading when I write about using antifreeze or brake fluid
in developers.