single agent developers
d23
have been unable to find one using only hydroquinone. Is there a reason, or
have I just not looked hard enough?
Thanks
Michael A. Covington
"d23" <d23n...@attbi.com> wrote in message
news:X8h5a.197447$Ec4.2...@rwcrnsc52.ops.asp.att.net...
Some developers used in the graphic arts use only hydroquinone. In general,
hydroquinone by itself produces low film speed and high contrast, or so I am
told.
There is a possibility that Kodak HC-110 uses hydroquinone as its only
developing agent, but I don't think so myself. See
www.covingtoninnovations.com/hc110.
--
Clear skies,
Michael Covington -- www.covingtoninnovations.com
Author, Astrophotography for the Amateur
and (new) How to Use a Computerized Telescope
Nick Zentena
The darkroom cookbook lists a few Agfa/Ansco paper developers. After
checking the MSDS for the store bought one I use it seems to be just
hydroquinone.
Nick
Garry D. Lewis
> "d23" <d23n...@attbi.com> wrote in message
> news:X8h5a.197447$Ec4.2...@rwcrnsc52.ops.asp.att.net...
> > There are many single agent developer formulas--d23 comes to mind. But I
> > have been unable to find one using only hydroquinone. Is there a reason,
> or
> > have I just not looked hard enough?
> > Thanks
>
Chlorhydroquinone(Aurdol or C.H.Q.[historical names]) -- Champlin #16
and Edwal #36.
yours quoting from history,
Garry D. Lewis
Michael A. Covington
"Nick Zentena" <zen...@hophead.dyndns.org> wrote in message
news:l3653b.0b8.ln@barley...
You can't necessarily trust an MSDS because relatively nontoxic agents
apparently do not have to be listed if they are present in low
concentrations. This is the root of the long controversy as to whether
HC-110 contains an agent other than hydroquinone.
Bill Troop
>There is a possibility that Kodak HC-110 uses hydroquinone as its only
>developing agent, but I don't think so myself. See
>www.covingtoninnovations.com/hc110.
There isn't any possibility. It uses a phenidone derivative. The
amount is so small it does not have to be listed on the MSDS.
It is probably possible to get hydroquinone to work as a reasonably
low contrast developer with some tanning action, but probably some
loss in speed.
Try 0.5g HQ, 2g sod sulfite, 3 g sod carb anh, to one litre of water.
Try a developing time of 12 minutes. Make up fresh: don't store. It
would be interesting to know how this worked out. Given the propensity
of the reaction products of HQ to accelerate development, my hopes are
not high. You could control this with sulfite. More sulfite would mean
less reaction product, and lower contrast. But the mechanism may be
different in such a weak developer as I have proposed here. Although I
do not expect it, it would not astonish me if this trial developer
produced reasonably low contrast and a reasonable speed. Needless to
say, there is not a single commercial developer for pictorial film or
paper that uses only HQ.
Nick Zentena
>
>
> You can't necessarily trust an MSDS because relatively nontoxic agents
> apparently do not have to be listed if they are present in low
> concentrations. This is the root of the long controversy as to whether
> HC-110 contains an agent other than hydroquinone.
Fair enough. The one I looked at seemed to be very similar to the Agfa
developers in the "Darkroom Cookbook". From the MSDS the only difference was
the addition of gylcol and one other chemical. Considering the pH is
supposed to be 11.5 I just assumed it didn't include anything else.
Nick
Nick Zentena
>
> It is probably possible to get hydroquinone to work as a reasonably
> low contrast developer with some tanning action, but probably some
> loss in speed.
>
> Try 0.5g HQ, 2g sod sulfite, 3 g sod carb anh, to one litre of water.
> Try a developing time of 12 minutes. Make up fresh: don't store. It
> would be interesting to know how this worked out. Given the propensity
> of the reaction products of HQ to accelerate development, my hopes are
> not high. You could control this with sulfite. More sulfite would mean
> less reaction product, and lower contrast. But the mechanism may be
> different in such a weak developer as I have proposed here. Although I
> do not expect it, it would not astonish me if this trial developer
> produced reasonably low contrast and a reasonable speed. Needless to
> say, there is not a single commercial developer for pictorial film or
> paper that uses only HQ.
How about the Agfa's paper developers? Do you know what else is in their
Multicontrast developer?
Would the formula you've given work with a high contrast lith film to get
a normal contrast result? If so I'll remember to order the film and give it
a try but I'll have to sub in Vit C.
Nick
Michael A. Covington
"Bill Troop" <bi...@graphos.org> wrote in message
news:3oic5vsl5v53g4kn7...@4ax.com...
>
> >There is a possibility that Kodak HC-110 uses hydroquinone as its only
> >developing agent, but I don't think so myself. See
> >www.covingtoninnovations.com/hc110.
>
> There isn't any possibility. It uses a phenidone derivative. The
> amount is so small it does not have to be listed on the MSDS.
Bill, do you have any confirmation of this other than the things already
noted on www.covingtoninnovations.com/hc110 (i.e., the apparent patent, and
someone's experiment demonstrating superadditivity with ascorbate)?
Thanks,
Michael
Dan Quinn
"...using only hydroquinone." I've read some, reasoned some,
and experimented some.
Metol is a high energy, nonselective agent. At high ph it will
develop everything.
Hydroquinone is a low energy, selective agent. A high ph will
cause it to develope the more exposed areas. At a low ph it acts to
regenerate other agents.
Ascorbic acid is a mistery; at least the ascorbic I've got. It
came from Photo. Formulary and should be good. It is very acid. It
may be similar to hydroquinone. In dual agent formulas it takes the
place of the hydroqinone. I've read though of it working alone with
film and paper. I've not been able so far, to duplicate the results.
Pota, uses phenidone alone. Dr. Beer's A-B print developer has
only hydroquinone in part B, as does a least one warm tone print de-
veloper I found.
Is'nt Glycine a stand alone agent? Dan
John
One could make a stand developer with hydroquinone. You would need the
longer induction time for the shadow areas to develop as much as possible and
lower the over all contrast of the image.
Regards
John S. Douglas Photographer & Webmaster
Formulas, Facts and Info on the Photographic Process
http://www.darkroompro.com
Bill Troop
>noted on www.covingtoninnovations.com/hc110 (i.e., the apparent patent, and
>someone's experiment demonstrating superadditivity with ascorbate)?
I know for two reasons, but none of them rate as "confirmation". There
isn't any confirmation worth a damn outside of the manufacturer's
mixing sheet. But I know. First, I know because I know. It's
inconceivable that anyone would make an HQ-only developer for
pictorial film or paper today. It would have undesirable image
characteristics and would be terribly uneconomical. The economics of
chemistry essentially forces superadditivity upon the manufacturer.
All of these people who read MSDSs and jump to the conclusion that HQ
is the sole developing agent are simply ignoring the fact that a
manufacturer does not have to list ingredients under 1 or 2 % (I
forget which); and as a result, rarely does so.
Second, I know because Dick Henn, who formulated the developer, told
me so.
In any case, it's a changeable formula. Ultimately, we can't know
what's in any particular batch without analyzing it, and even then,
there are plenty of ways to trick analysis.
Bill Troop
>Multicontrast developer?
Agfa having patented some interesting aminopyrazoline concentrated
developers with high resistance to oxidation and hydrolysis in
alkaline solution, I would place a bet in that direction. Whatever it
is, you can be sure it's something besides HQ, and that the amount is
sufficiently small not to have to listed on the MSDS. You can find a
discussion of this in Haist v.1
> Would the formula you've given work with a high contrast lith film to get
>a normal contrast result?
No. The developer I proposed is much too weak to have a lith effect.
Lith development is very complex. There's a good discussion again in
Haist v. 1, Oh. You want to work with lith film to get a normal
contrast result? But why would you try to do this? In any case, the
formula I proposed is just there to show that it is possible to make a
low contrast, tanning developer out of HQ is you really don't have
anything else to work with. Undoubtedly, however, pyrocatechin would
be a better choice for this kind of developer.It would be interested
to compare the speed of HQ and pyrocatechin in this kind of highly
dilute formulation (i.e. a half gram/litre of developing agent,
carbonate alkalinity). But what I don't understand is why you would
want to get normal contrast out of a lith film? That's what lith
emulsions are expressly designed for.
>If so I'll remember to order the film and give it
>a try but I'll have to sub in Vit C.
I don't understand what you mean here. Could you elaborate? You
certainly cannot get a lith effect with a Vit. C developer. HQ is by
far the most desirable developing agent for the lith effect -- much
better than the bromo, chloro or toluhydroquinone variants. However,
vit. C has been used as an anti-oxidant agent in lith developers, as
Haist noted. This was one of the secrets of the Pako lith developers.
Lith developers require low sulfite (to get the reaction products
going) and thus are unstable, usually requiring to be mixed just
before use. It seems that vit. C can confer some stability without
ruining the lith effect.
Bill Troop
> One could make a stand developer with hydroquinone. You would need the
>longer induction time for the shadow areas to develop as much as possible and
>lower the over all contrast of the image.
John is right, but I think it would be problemmatical in practice. The
reason glycin is used in stand developers is that is believed to have
high resistance to aerial oxidation. An HQ developer weak enough to
work as a stand developer would probably produce streaking and all
kinds of other unwanted side effects. It would also be likely to bomb
out, I would guess.
Bill Troop
single agent formula anymore? I don't think so. If you look at the
MSDS, concentrations are way below what you would expect, knowing that
the oft-published 'traditional rodinal' formulas perform very
similarly. I am thus convinced that Agfa is using one of the hundreds
of agents they have studied for superadditivity with para aminophenol.
Bob Schwalberg had managed to persuade his old pals at Agfa to let him
publish most of the proprietary formulas except of course the current
one. His untimely death put an end to this project, which would have
interested so many here. All I learned from Bob was that the formula
we know as traditional Rodinal, which we had all suspected to have
been used commercially by Agfa for decades was, according to Bob's
informants, never used in the commercial product.
A consultant chemist I used to know told me that many of the earlier
manufacturing formulas are available -- if you know where to look for
them. Some undoubtedly in the Library of Congress, others in less
recondite places. I asked him to get some of this material for the
Film Developing Cookbook, but he wouldn't do it without getting paid a
reasonable sum of money, doubtless much more than I will ever receive
in royalties.
So I didn't get the information. You win some, you lose some.
Michael A. Covington
> >Bill, do you have any confirmation of this other than the things already
> >noted on www.covingtoninnovations.com/hc110 (i.e., the apparent patent,
and
> >someone's experiment demonstrating superadditivity with ascorbate)?
>
> inconceivable that anyone would make an HQ-only developer for
> pictorial film or paper today. It would have undesirable image
> characteristics and would be terribly uneconomical.
> In any case, it's a changeable formula. Ultimately, we can't know
> what's in any particular batch without analyzing it, and even then,
> there are plenty of ways to trick analysis.
Thanks very much. I suppose that, by definition, if the 2 compounds
interact in a useful way, they're going to be hard to separate by analysis.
What do you know about the initial introduction of HC-110? I have never
been able to find an advertisement for it!
Nick Zentena
> Haist v. 1, Oh. You want to work with lith film to get a normal
> contrast result? But why would you try to do this? In any case, the
Freestyle sells lith sheet film for about 1/4 the price of the lowest
priced B&W film. In addition it's slower. With the majority of my lenses not
having shutters the slow speed is enough to make it interesting. I've been
collecting hints on how to get normal contrast out of it. Some one suggest
D-72 at 1:10. The combination of the cost and that it can be processed with
the safelight makes it a perfect learner film. If I can get normal contrast
out of it.
>
>>If so I'll remember to order the film and give it
>>a try but I'll have to sub in Vit C.
>
> I don't understand what you mean here. Could you elaborate? You
> certainly cannot get a lith effect with a Vit. C developer. HQ is by
Well I have Vit C in the house. If it would work I'd rather sub in that
and adjust for the acidity then buy HQ for just this.
Nick
Bill Troop
reasons for wanting to get normal contrast out of lith film.
In that case, I see no reason to use HQ. Why not try D-76 and see what
happens? I would expose at a variety of speeds, and develop at, say,
3,5,7,10, and 14 minutes. Once you got the results from that, it would
be easier to suggest something else for you.
I have no experience with lith films, so all I can give you is
reasonably intelligent guesses. I see no reason to use either HQ or
Vit. C. When you say Vit. C do you mean Vit. C or do you mean sodium
isoascorbate, which is the only form I would recommend?
If the film is slow and inherently of high contrast, I see nothing to
be gained by using an inherently high contrast developer.
I'd love to know how this works out. Sounds like you might get some
interesting results. I assume you'll be making quite large negatives?
Bill Troop
>interact in a useful way, they're going to be hard to separate by analysis.
Also, Michael, please consider that everyone who makes a commercial
formula adds a little of this and that -- chemicals known to make
accurate analysis almost impossible.
>What do you know about the initial introduction of HC-110? I have never
>been able to find an advertisement for it!
That's a very interesting question. I know nothing about it. It may be
that at first Kodak didn't advertise it heavily, not knowing quite
what to do with it. I know Kodak people who strongly dislike it, for
its (in their view) unnecessarily high solvent effect. It may be one
of those products like Adobe Acrobat, that nobody knew what to do with
when they first came out -- but which established valuable uses and
large numbers of users as time went on.
As I said in my book, what impresses me most about HC-110 is the
environmentally-friendly aspect. The chemicals per se are not that
friendly, but, because of the composition, you need to use about ten
times less of the chemicals than would normally be required. That's a
pretty valuable achievement. What is interesting is that nobody has
thought it worthwhile to extend the technology to other developers. We
know that there must be some great manufacturing difficulties, which
probably are due to the necessity of having particular grades of
particular chemicals. So often, the success of a commercial formula
depends very closely on the precise grade of chemical used. That may
be hard to obtain as time goes on -- grades may get less pure, and
even when they get more pure, they may not work. Sometimes a formula
depends on particular impurities.
That's one reason why one should try to keep formulas as simple as
possible. Even metol has changed considerably over the years, as Haist
documents at various points in his book.
Mike King
Kodalith ortho in the camera since I could load it by red safelite.
Processed the film in D-76 1:1 for a Tri-X time. Too contrasty? Try POTA
or any of the brew's intended to tame Tech Pan.
--
darkroommike
----------
"Bill Troop" <bi...@graphos.org> wrote in message
news:qqfi5v43kkh7c4lfg...@4ax.com...
Robert L. Vervoordt
Sad, so sad. I remember Bob Shwalberg from the old Pop Photo days.
He was a force in photographic writing.
I began photography in the early 50s and started formulating my own
from anything I could read. If anyone wants to dig into this subject,
I recommend checking out old photo books at a public library. the old
books led me to:
Metol, Glycin, Pyrogallol, Pyrocatechin, Paraminphenol (Rodinal),
Amidol, Hydroquinone, Parapenylenediamine (and derivative salts),
Chlorohydroquinone and Eikonogen. I may have forgotten a few.
Of these, I found Metol, as John Douglas and John Hicks recommend in
D23and its variants, Glycin, Paraminophenol, Chlorohydroquinone, some
Paraphenylenediamine salts and Eikonogen to produce useable pictorial
results in their various formulations.
The Paraphenylrnediamine salts were the modern color developing agents
such as Ansco's Dicolamine, Kodak's CD-1, CD-3 and CD-4. Of these,
CD-4 was the most useful. This is also borne out by folks using the
C-41 color developer for Tech Pan. I did find that they benefited
from use in a Sease type formula by including Glycin, at least for BW
negatives; never thought to try this out with color film.
The Eikonogen I used was not exactly the original item, but rather an
equivalent compound with a similar structure. I got it from City
Chemical in NYC some years ago. Its use was given as a dye
intermediary.
I seem to recall its designation as 1,2,4, Betaphenyethylamine or Beta
something else. (Please correct me on this, as I can't access my
records.) It may be the same agent used in Promicrol, as I recall
from reading that patent. Promicrol was a 2 agent developer combining
the beta compound with Glycin, making something like a Sease formula
variant; that one worked, too.
For my first attempt with this compound as a single agent I used 5
grams of the agent with 20 to 50 grams of Metaborate and 50 grams of
Sulfite in a liter of solution. I can't remember the film I used or
the time of development, but it developed negs with full speed, proper
tonality, grain, sharpness and no fog. In all, a successful item on
first use with no bad surprises.
Hope this helps someone along the road to experimentation with their
own work, Looks like this might be right up some dude's alley. )-D
Cheers,
Robert Vervoordt
Richard Knoppow
reports made after WW-2. There were several intelligence
gathering investigating bodies operating at the time from
the USA and England and a couple of joint bodies. They
examined all of German industry and published everything.
Lots of trade secrets there. I no longer remember all the
abbreviations of these groups. One was BIOS, a British
group, I suspect there are others in the group who will
remember.
I surveyed some of this stuff many years ago when
researching sound recording technology. I currently have a
couple of publications describing lens manufacturing at
Zeiss. I know there is at least one publication with
complete information on optical glass manufacture at Schott.
It would be interesting to know the stages Rodinal has
gone through since color changes, etc., indicate the formula
or at least method of production, has changed over the
decades its been made.
--
---
Richard Knoppow
Los Angeles, CA, USA
dick...@ix.netcom.com
Richard Knoppow
inactive at low pH. By the time the pH is increased enough
for reasonable activity the contrast becomes high.
However, there have been some paper developers using
Hydroquinone as the sole developing agent, particularly for
very warm tones. These developers, however, loose emulsion
speed. I suspect the current packaged Agfa Neutol WA is a
combination of developers, probably containing Glycin.
However, Agfa has used some unusual reducing agents in its
commercial products. I've forgotten what is in Rodinal
Special or Studional but they contain something other then
the common agents.
An example of a Hydroquinone warm tone developer is:
Agfa 110 Direct Brown-Black Developer
Stock Solution
Water (at 125F or 52C) 750.0 ml
Hydroquinone 22.5 grams
Sodium Sulfite, dessicated 57.0 grams
Sodium Carbonate, monohydrated 75.0 grams
Potassium Bromide 2.75 grams
Water to make 1.0 liter
For use dilute 1 part stock solution with 5 parts water.
Prints require 3 to 4 times normal exposure. Develop for 5
to 7 minutes at 68F
Agfa published similar formulas over the years under a
couple of different designations.
Patrick Gainer
Dan Quinn wrote:
Many of today's RC papres have developing agent in the emulsion. A
strong enough alkali alone may in fact develop them. I used to develop
stabilazion papers in a tray of water and washing soda. Ascorbic acid
can be used effectively as a substitute for hydroquinone in most
developeer formulas. You must have enough alkali to restore the pH.
Ascorbate is not very good by itself. It will show some of the
properties of hydroquinone if the pH is high enough. Development will
accelerate. Fog level will be high.
When i first heard about HC-110over 30 years ago, a friend told me it
contained a variety of phenidone which he called "methyl phenidone." I
am convinced by its behavior when I add ascorbate to it that it must
have something more that hydroquinone because HC-110 is very
superadditive with ascorbate.
John
>When i first heard about HC-110over 30 years ago, a friend told me it
>contained a variety of phenidone which he called "methyl phenidone." I
>am convinced by its behavior when I add ascorbate to it that it must
>have something more that hydroquinone because HC-110 is very
>superadditive with ascorbate.
I am still somewhat skeptical of these theories as any
Phenidone-containing formula would develop a high amount of base-fog at the
working pH of HC110. Also note that most photographers that use it find about
1/2 stop speed loss at least. Not a common characteristic of a PQ developer.
Michael A. Covington
"Patrick Gainer" <pga...@rtol.net> wrote in message
news:3E5DAD6D...@rtol.net...
> When i first heard about HC-110over 30 years ago, a friend told me it
> contained a variety of phenidone which he called "methyl phenidone." I
> am convinced by its behavior when I add ascorbate to it that it must
> have something more that hydroquinone because HC-110 is very
> superadditive with ascorbate.
Kodak Dimezone can be described as di-methyl-Phenidone. More evidence that
that's what it is...
Michael A. Covington
"John" <jo...@darkroompro.com> wrote in message
news:9dgr5v82fn54per8u...@4ax.com...
> On Thu, 27 Feb 2003 01:17:17 -0500, Patrick Gainer <pga...@rtol.net>
wrote:
>
> >When i first heard about HC-110over 30 years ago, a friend told me it
> >contained a variety of phenidone which he called "methyl phenidone." I
> >am convinced by its behavior when I add ascorbate to it that it must
> >have something more that hydroquinone because HC-110 is very
> >superadditive with ascorbate.
>
> I am still somewhat skeptical of these theories as any
> Phenidone-containing formula would develop a high amount of base-fog at
the
> working pH of HC110. Also note that most photographers that use it find
about
> 1/2 stop speed loss at least. Not a common characteristic of a PQ
developer.
True; that is the one big difference between HC-110 and the other
Phenidone-based developers I've known. HC-110 produces the same speed as
D-76 or a little less. PQ developers produce half a stop more speed.
HC-110 is also quite fog-free (even with the hydrogen-baked film we use in
astronomy); Microphen, for instance, gives heavy fog with such films.
Could this be due to a stronger than normal restrainer?
John
<lo...@www.covingtoninnovations.com.for.address> wrote:
>> I am still somewhat skeptical of these theories as any
>> Phenidone-containing formula would develop a high amount of base-fog at
>the
>> working pH of HC110. Also note that most photographers that use it find
>about
>> 1/2 stop speed loss at least. Not a common characteristic of a PQ
>developer.
>
>True; that is the one big difference between HC-110 and the other
>Phenidone-based developers I've known. HC-110 produces the same speed as
>D-76 or a little less. PQ developers produce half a stop more speed.
>HC-110 is also quite fog-free (even with the hydrogen-baked film we use in
>astronomy); Microphen, for instance, gives heavy fog with such films.
>
>Could this be due to a stronger than normal restrainer?
It would be a possibility but it would take a lot and it would be listed
in the MSDS. Nothing in it catches my eye. Benzotriazole would probably be used
as bromide would be ineffective against Phenidone at the ~9pH of HC110.
Robert L. Vervoordt
Wait, now hasn't somone in another thread used HC-110 as a stand
developer?
If so, a few thoughts come to mind, particularly in light of the
Catechol and the Diethanolamine-sulfur dioxide complex in the MSDS
linked to from Michael's page.
What if there was another agent in addition to HQ in there in a lower
than usual amount and lower toxicity, such that it didn't have to be
listed?
Might this be Glycin?
Given the low level of HQ in a working solution and assuming the
inclusion of Dimezone, perhaps the need for additional superadditivity
at low toxicity recommended the use of Glycin. As Richard observed,
Agfa has used Glycin in a lot of their products, and I remember the
use of Glycin in Promicrol's patent. This is from Bill Troops book:
PROMICROL
Hydroxyethyl-o-aminophenol 6 g
Sodium sulfite anhydrous 100 g
Glycin 1.16 g
Sodium carbonate anhydrous 11.5 g
Water to make one liter.
Here's another, linked:
http://www.jackspcs.com/fx11.htm
The small amount in these formulae point up the additivity of Glycin
with HQ and the Hydroxyethyl-o-aminophenol, which is related to the
Beta compound I mentioned in my earlier post. Ilford patented the
superadditivity of GLycin with Phenidone early on.
A likely scenario at Kodak may have been that they wanted to get
around the Ilford patent, and did it by patenting Dimezone. Somebody
played around and came upon the extra superadditivities and made up an
early version of HC-110 with Catechol and while at it went for the
Diethanolamine-sulfur dioxide complex and other exotic compounds. The
resulting brew was interesting in that it was environmentally
friendly, gave a lot of solvent action and preservative, could be made
into a concentrated solution that could be highly diluted and still
work well enough and had a very low fog level. Should have been good
for something, I'd say.
Some clues are in the very high solvent action, even when highly
diluted, lack of fog, staining streaking and good keeping properties
in solution all point to Glycin as a possibility.
Another aspect could be the use of the HQ salt that Kodak patented for
their color reversal first developers. This was called Hydroquinone
Monosulphonate, if I recall correctly, and it was essentially half
strength HQ that proved to be more stable and longer lasting in a
working solution. Being less active, it also was claimed to give less
fog and contrast. Use of this would get Kodak right out from under
Ilford's patent on superadditivity of Phenidone and Glycin.
After that, if they slipped in a little Ascorbate, no one would know
as it wouldn't show on the MSDS.
A neat trick, if that's what they did.
Regards,
Robert Vervoordt
Bill Troop
>
>True; that is the one big difference between HC-110 and the other
>Phenidone-based developers I've known. HC-110 produces the same speed as
>D-76 or a little less. PQ developers produce half a stop more speed.
>HC-110 is also quite fog-free (even with the hydrogen-baked film we use in
>astronomy); Microphen, for instance, gives heavy fog with such films.
>
>Could this be due to a stronger than normal restrainer?
>
extra speed does not mean that they all do!!!!! HC-110 is a highly
solvent developer; it is formulated first and foremost to use the
absolute minimum amount of chemistry. It achieves usage levels of
chemicals at least 10 times less than any comparable formula. There is
_no_ way you can compare what happens in HC-110 to what happens in any
other developer, because the use of the ammonia salts changes
everything about the way the developer works.
As to Dimezone, it was not patented to get around Ilford's patent. It
was invented because phenidone is simply not adequately stable in most
alkaline solutions. Dimezone is much more stable, but is much more
difficult to dissolve. It is also clearly superadditive with Dimezone.
This discussion about whether HC-110 does or not contain Dimezone is
just silly. Of course it does. If anyone doubts that, let them get it
analyzed.
By the way, I see no reason to assume that Benzotriazole is used in
HC-110. We know that Kbr can lose effectiveness in phenidone formulas
as pH rises. But HC-110 does not use Kbr. It uses imniodiethanal
hydrobromide, and no one has yet suggested that this is an ineffective
antifoggant for Dimezone at high pH, as far as I know.
If you dilute the formula in patent 3,522,060 by 100, you have a
working solution with just 0.005g phenidone/dimezone and 0.06 g HQ.
Does anyone really think that is enough to produce a speed gain?
It is perfectly possible to create a speed-_losing_ PQ developer if
you want to. -- And Kodak at the time of HC-110 had an adamant mind
set against speed-increasing developers.
Finally, I find it difficult to believe that any widely available
commercial developer today uses glycin. Glycin is too expensive to use
in commercial products.
Isn't there someone on this list who can do some analysis and answer
some of these questions more defintiively?
John
On Fri, 28 Feb 2003 22:01:10 GMT, Bill Troop <bi...@graphos.org> wrote:
>>True; that is the one big difference between HC-110 and the other
>>Phenidone-based developers I've known. HC-110 produces the same speed as
>>D-76 or a little less. PQ developers produce half a stop more speed.
>>HC-110 is also quite fog-free (even with the hydrogen-baked film we use in
>>astronomy); Microphen, for instance, gives heavy fog with such films.
>>
>>Could this be due to a stronger than normal restrainer?
>
I think it's safe to say that we disagree ;>)
>Of course it is.
Then what is used as a restrainer ? I don't know of one that is non-toxic
and there would be a significant amount in the concentrated formula of HC-110.
Enough that it would have to be included on the MSDS.
>Also, just because _some_ PQ developers give 1/2 stop
>extra speed does not mean that they all do!!!!!
They don't all have a speed gain but they all at least "break even". Also
many PQ formulas are capable of delivering more than half a stop of speed.
>HC-110 is a highly solvent developer
It's solvency is on par with Rodinal and FX-1 as has been noted by many
photographers. Also note that the amount of sulfite per liter of Dil. B is less
than 1/6 the amount used in most developers. Did you mean soluble ?
>; it is formulated first and foremost to use the
>absolute minimum amount of chemistry.
"HC" as in Highly Concentrated.
> It achieves usage levels of
>chemicals at least 10 times less than any comparable formula.
It is efficient but it's simply because of the strongly alkaline solution
and low amount of sulfite in the working stock. It is known (Haist v.1, p.301)
that hydroquinone will produce semiquinones when reducing the silver halide and
that these semiquinones are in effect super-additive with hydroquinone. I
propose that this is part of the cycle that gives HC110 its' upswept curve. It
may also be part of the manner in which HC-110 starts it's entire development
cycle. Much like a litho developer actually.
> There is
>_no_ way you can compare what happens in HC-110 to what happens in any
>other developer, because the use of the ammonia salts changes
>everything about the way the developer works.
And what about other developers that use similar components ? T-Max/RS,
DD-X and a few others are probably very similar.
>As to Dimezone, it was not patented to get around Ilford's patent.
Of course it was ! Show me one time that E.K. actually paid patent rights
on something ? Why would they ? Not only do they have really deep pockets but
they own their own labs !.
>It was invented because phenidone is simply not adequately stable in most
>alkaline solutions.
And as I recently told you, I have some marvelously ripe 2.5 year old
Microphen that seems to be doing quite well. Is Ilford using a different
derivative now ?
> Dimezone is much more stable, but is much more
>difficult to dissolve.
Which is why E.K.formulated the Dimezone-S for Xtol. See U.S.Pat. #
6,083,673 for some interesting info on the Dimezone derivative development.
> It is also clearly superadditive with Dimezone.
>
>This discussion about whether HC-110 does or not contain Dimezone is
>just silly.
I agree.
>Of course it does. If anyone doubts that, let them get it
>analyzed.
Would that I could afford such an endeavor but with one in diapers and one
on the way !
>By the way, I see no reason to assume that Benzotriazole is used in
>HC-110.
You know of another restraining agent that is effective in extremely
small, non-toxic quantities against Phenidone ?
>We know that Kbr can lose effectiveness in phenidone formulas
>as pH rises.
KBr is virtually ineffective from the start, never mind after the pH
rises.Phenidone is more easily absorbed by the halide than KBr and therefore
it's simply ineffective. The only agents that are effective at controlling
Phenidones development are the organics such as benzotriazole and
1-Phenyl-5-mercaptotrazole.
> But HC-110 does not use Kbr. It uses imniodiethanal
>hydrobromide, and no one has yet suggested that this is an ineffective
>antifoggant for Dimezone at high pH, as far as I know.
Please show me a document that mentions this chemical. I have read most of
Mr.Haist' and Mr.Meese' works but have not come across this name before nor is
it listed in any of the 3 Focals Encyclopedias that I own. Do you mean
cyclohexylamine hydrobromide ?
>If you dilute the formula in patent 3,522,060 by 100, you have a
>working solution with just 0.005g phenidone/dimezone and 0.06 g HQ.
Patent # 3,522,060 is for "Process for Preserving Plant Material in a
Fresh State".
So now you are proposing that there is a minuscule amount of Dimezone and
a micro-scule amount of restrainer ? Bill, Kodak can't even measure out the
ingredients for Xtol properly !
BTW, Microphen at 1:4 has 1.0g of hydroquinone and 0.03g of Phenidone and
will develop T-Max 400 to EI 400 in around 24 minutes at 70F.
>Does anyone really think that is enough to produce a speed gain?
Yes, given the elevated pH of the working solution, the effect of any
Phenidone on the development cycle would be very significant.
>It is perfectly possible to create a speed-_losing_ PQ developer if
>you want to. -- And Kodak at the time of HC-110 had an adamant mind
>set against speed-increasing developers.
I know of no PQ formulas for normal panchromatic films that looses speed.
Some such as T-Max Developer show less of a speed gain than say Microphen but
none actually loose emulsion speed.
Also, I wonder why Kodak would be dis-interested in speed-producing
developers given that most photographers under-rated their films at least 1 full
stop.
>Finally, I find it difficult to believe that any widely available
>commercial developer today uses glycin. Glycin is too expensive to use
>in commercial products.
Too unstable as a powder, too limited in availability and too insoluble.
Adds up to too expensive for what is essentially a niche industry.
>Isn't there someone on this list who can do some analysis and answer
>some of these questions more defintiively?
I'm working on it !
Honestly Bill, don't you think it's safe to say that if HC-110 had either
Phenidone or a restrainer in it that one-or-the-other would show up on the MSDS.
Bill Troop
>>>Phenidone-based developers I've known. HC-110 produces the same speed as
>>>D-76 or a little less. PQ developers produce half a stop more speed.
If you look at the patent for HC-110 (3,522,969 -- sorry, I mistyped
it before) you will see that a primary concern was not losing emulsion
speed in this type of formulation. It is completely inaccurate to
think that phenidone developers automatically confer a half-stop extra
speed. Some very carefully formulated instances arguably do. Others do
not, nor do they make any claim to do so. In HC-110, the formulators
considered themselves lucky to get rated emulsion speed, given the
difficulties of balancing the highly solvent, dichroic-fog producing
organic amines, with the antistain agent (PVP).
> Then what is used as a restrainer ? I don't know of one that is non-toxic
>and there would be a significant amount in the concentrated formula of HC-110.
>Enough that it would have to be included on the MSDS.
Since when John are you an expert on what does or does not have to be
included in an MSDS? If you have a look at the typical requirements,
you'll see that there is enormous flexibility. Haist lists
2,2'-Iminodiethanol hydrobromide at 1.5g/L as the typical antifoggant
in HC-110. That would not have to be included, I don't think. Another
very popular Kodak antifoggant, which is never present in amounts
sufficient to need to be included in an MSDS, is
1-phenyl-5-mercaptotetrazole. In any case, a developer does not have
to include a restrainer and, arguably, should not contain a
restrainer. XTOL, for example, does not; neither does D-76. As Grant
Haist has remarked (and as I quoted him in FDC), "If you've got too
much fog, you've got too much alkali." (Neither does traditional
Rodinal contain a restrainer; but the commercial version does; it also
obviously contains a very significant developing agent not listed in
the MSDS which necessitates the restraint.)
>>Also, just because _some_ PQ developers give 1/2 stop
>>extra speed does not mean that they all do!!!!!
>
> They don't all have a speed gain but they all at least "break even".
They "all" do? You have tested every known formulation? Look John, you
are completely at sea here because you are trying to apply the
knowledge you have (developers that do not contain organic amines) to
an area of photographic science where you have no knowlege (developers
that do condtain organic amines). Everything changes when you use
organic amines. You're in a different universe.
>>>HC-110 is a highly solvent developer
>
> It's solvency is on par with Rodinal and FX-1 as has been noted by many
>photographers. Also note that the amount of sulfite per liter of Dil. B is less
>than 1/6 the amount used in most developers. Did you mean soluble ?
John, you are completely mistaken. The amines that are the entire
basis of HC-110 are highly solvent, much more so than sodium sulfite.
HC-110 is highly solvent, and would produce dichroic fog except for
the presence of the antistain agent (PVP). It is certainly considered
as such by Kodak people (S. Zawadzki; the late R. Henn). In fact,
Zawadzki strongly criticized me for, in her view, inaccurately
classifying HC-110 as non-solvent developer, and XTOL as a solvent
developer. She is right. I was wrong. HC-110 has reasonably high
definition, due to sharpness-enhancing effects caused by developer
exhaustion _and_ by the solvent action. (Always remember that there
are strong sharpness enhancing effects in highly solvent developers,
such as monobaths, and HC-110.) When photographers, as you say, "note"
that HC-110's "solvency" is on a par with that of FX-1 or Rodinal,
they are talking through their hats. Photographers have no way of
measuring solvency. What photographers _can_ do is to observe whether
development is sharp or not. HC-110 is _very_ sharp, in part because
of its clever exploitation of the solvent effects of the organic
amines. In any case, I would argue that for conventional films, FX-1
is much sharper than any of the other developers you mention. HC-110
is also highly diliute, so additonal adjacency effects are created
through developer exhaustion.
> It is efficient but it's simply because of the strongly alkaline solution
>and low amount of sulfite in the working stock. It is known (Haist v.1, p.301)
>that hydroquinone will produce semiquinones when reducing the silver halide and
>that these semiquinones are in effect super-additive with hydroquinone.
Your reasoning is off base, and this is because you understand nothing
about working with organic amines. The pH of HC-110 is 8.8 to 9.0,
which is only fractionally higher than the pH of D-76. No, I would not
call HC-110 highly alkaline You also fail to grasp that the reaction
products of hydroquinone produce high contrast, which would make
pictorial film development impossible. In an MQ or PQ developer, the
overwhelming balance of the reaction products produce low contrast.
In any case, pH is not a reliable guide to developer activity when you
are talking about organic amines. Organic amines cause a developer to
be much more active than a much higher pH developer that used
carbonate, phosphates, or hydroxide.
>I propose that this is part of the cycle that gives HC110 its' upswept curve. It
>may also be part of the manner in which HC-110 starts it's entire development
>cycle. Much like a litho developer actually.
If you really think this is the case, then why don't you make a
diethanolamine-HQ-PVP developer yourself and test it out? You will
find that you will get very low speed and very high contrast. Trust me
on this one!
>
>> There is
>>_no_ way you can compare what happens in HC-110 to what happens in any
>>other developer, because the use of the ammonia salts changes
>>everything about the way the developer works.
>
> And what about other developers that use similar components ? T-Max/RS,
>DD-X and a few others are probably very similar.
You can't generalize that much. So much depends on the dynamics of the
inividual formula.
>
>>As to Dimezone, it was not patented to get around Ilford's patent.
>
> Of course it was ! Show me one time that E.K. actually paid patent rights
>on something ? Why would they ? Not only do they have really deep pockets but
>they own their own labs !.
>
>>It was invented because phenidone is simply not adequately stable in most
>>alkaline solutions.
>
> And as I recently told you, I have some marvelously ripe 2.5 year old
>Microphen that seems to be doing quite well. Is Ilford using a different
>derivative now ?
If it's 2 and a half years old, it's not phenidone, which would long
since have bombed out. It's either the 4-methyl form (Phenidone B) or
the 4-dimethyl form (Dimezone). Phenidone is useless in liquid
concentrates because it simply does not last long enough. Now that the
patents on all of these chemicals have long expired, I find again and
again when I talk to chemists that Dimezone is considered the best all
round choice. But the long experience that has shown this to be true
is still considered trade secret. For gosh sakes, do you expect
manufacturers to shout this kind of stuff from the rooftops, so that
every jerk can start manufacturing chemistry in his bathroom?
>> It is also clearly superadditive with Dimezone.
What I meant to write there is that pyrocatechin is clearly
superadditive with Dimezone.
>>By the way, I see no reason to assume that Benzotriazole is used in
>>HC-110.
>
> You know of another restraining agent that is effective in extremely
>small, non-toxic quantities against Phenidone ?
Yes. 1-phenyl-5-mercaptotetrazole, which could be used in quantities
100 times less than BZT. But the amine bromide listed in the patent is
most likely the one still used, for a wide variety of reasons. BZT
would not be adequately active at the comparatively low (sorry John!
but check the MSDS!) pH of HC-110. I can't think of any reason why a
manufacturer would use BZT in a negative developer today. There is
also the additional problem that the grades of BZT being manufactured
today are very poor. By contrast, it is still possible to get
excellent Kbr.
>>We know that Kbr can lose effectiveness in phenidone formulas
>>as pH rises.
>
> KBr is virtually ineffective from the start, never mind after the pH
>rises.Phenidone is more easily absorbed by the halide than KBr and therefore
>it's simply ineffective. The only agents that are effective at controlling
>Phenidones development are the organics such as benzotriazole and
>1-Phenyl-5-mercaptotrazole.
You are completely mistaken. The organic antifoggants are only
effective in phenidone developers at a pH of 10 or higher. At pH 9 or
below, bromides or iodides are the antifoggant of choice.
>> But HC-110 does not use Kbr. It uses imniodiethanal
>>hydrobromide, and no one has yet suggested that this is an ineffective
>>antifoggant for Dimezone at high pH, as far as I know.
>
> Please show me a document that mentions this chemical. I have read most of
>Mr.Haist' and Mr.Meese' works but have not come across this name before nor is
>it listed in any of the 3 Focals Encyclopedias that I own. Do you mean
>cyclohexylamine hydrobromide ?
No. Read them again, and you'll find the chemical listed in the HC-110
patent, but you won't find any discussion of it. Do you think these
people are positively obliged to discuss every interesting chemical
that might be used in a commercial producdt? And by the way, if I may
just be a bit of a grammarian, the possessives of these two names are
Haist's and Mees's.
>
>>If you dilute the formula in patent 3,522,060 by 100, you have a
>>working solution with just 0.005g phenidone/dimezone and 0.06 g HQ.
>
> Patent # 3,522,060 is for "Process for Preserving Plant Material in a
>Fresh State".
See above for the correct patent number.
> So now you are proposing that there is a minuscule amount of Dimezone and
>a micro-scule amount of restrainer ? Bill, Kodak can't even measure out the
>ingredients for Xtol properly !
As every chemist involved in mixing will tell you, it is incredibly
difficult to mix chemicals for dry formulation accurately. But it is
very easy to mix chemicals for a liquid formulation accurately.
>
> BTW, Microphen at 1:4 has 1.0g of hydroquinone and 0.03g of Phenidone and
>will develop T-Max 400 to EI 400 in around 24 minutes at 70F.
Really? You know the actual formula of Microphen as manufactured?
That's something I myself have never come across. You must have some
very good contacts at Ilford. Please tell us more!
>
>>Does anyone really think that is enough to produce a speed gain?
>
> Yes, given the elevated pH of the working solution, the effect of any
>Phenidone on the development cycle would be very significant.
Again, you have two misconceptions: (1) you think HC-110 has a very
high pH. In reality, it is only half a unit higher than HC-110 --
barely enough to activate HQ!!!!. (2) you don't take into account the
fact that, with the chemistry used in HC-110, the formulator's two
biggest problems are (a) how to prevent speed loss and (b) how to
prevent dichroic fog. (In fact, if anything establishes at once that
HQ is not used by itself in HC-110, the specified pH does! Do you
seriously expect us to accept that a highly active, highly dilute
HQ-only developer has been formulated to work at pH 8.8?)
>>It is perfectly possible to create a speed-_losing_ PQ developer if
>>you want to. -- And Kodak at the time of HC-110 had an adamant mind
>>set against speed-increasing developers.
>
> I know of no PQ formulas for normal panchromatic films that looses speed.
>Some such as T-Max Developer show less of a speed gain than say Microphen but
>none actually loose emulsion speed.
Again, when you say something loses speed, there's only one o. If
something's on the loose, then it has two o's. I think we have
discussed the speed increasing issue adequately above.
>
> Also, I wonder why Kodak would be dis-interested in speed-producing
>developers given that most photographers under-rated their films at least 1 full
>stop.
You mean -un-interested, not -dis-interested. Kodak was of course
interested. But it never accepted that the claims for speed increase
were really true. Although I don't personally agree with their
position (basically held from 1950 to 1980), I think there is
considerable merit to it. The people who formulated these opinions
were not imbeciles. (I mean Rochester, of course. Other Kodak labs
held different opinions and made different products.)
>
> Honestly Bill, don't you think it's safe to say that if HC-110 had either
>Phenidone or a restrainer in it that one-or-the-other would show up on the MSDS.
No. It's time for you to lose your pathetic faith in MSDS's. Just like
with patents, a manufacturer uses these disclosures as much to conceal
as to reveal what is actually in the product. I can't believe that I
have wasted two hours of life responding to this not very well thought
out argument. If you really need to be convinced further, I suggest
you count to ten, and then call DIckerson, Zawadzki, or Haist, They'll
be able to set you straight.
And keep on reading your Haist! I've been reading it for 20 years, and
I still have only absorbed about 10% at best. Every time I look in it,
I find something vital that I missed on previous readings.
Bill Troop
drawing my attention to the incorrect last three digits in my citation
for the HC-110 patent, a mistake I continue to make; also John, Mees &
James, and Haist, are wonderful reference books, but the Film
Developing Cookbook does contain a few things they could not have
disclosed in their own writings. Also, for all its faults, FDC was
extensively reviewed before publication by S. Zawadzki, D. Dickerson,
G. Haist, and T.H. James. I think I can claim that it is accurate as
any other publication in photochem.
Obviously, there is one point I should have made clearer: no pictorial
contrast developer can contain hydroquinone alone, for the simple
reason that the reaction products of hydroquinone accelerate
development, leading to high contrast. Conversely, the reaction
products of metol and phenidone decelerate development, leading to low
contrast. In an MQ or PQ developer, the reaction products of M and P
dominate. The HQ's primary role is to regenerate the P or M. As I have
said, Zawadzki believes that ascorbate is the primary developing agent
in XTOL. Her opinion is obviously entitled to vastly greater weight
than mine, but I am not yet entirely convinced. Anyone who thinks
there are any ultimate answers in photography is crazy. The chemistry
is simply too illinear. This has been recognized by all the
researchers in the end.
Finally, although it is true that a theoretically high contrast
developing agent (such as pyrocatechin) can be formulated under very
limited circumstances to produce pictorial contrast with a normal
pictorial film, this is very difficult to achieve. I have proposed
earlier in this thread a tanning HQ developer that I think should
work, but I would expect substantial speed loss. Naturally, an HQ
developer will produce lower contrast if sulfite is very high and the
developing time is very brief, because, in that case, there is no time
for the contrast-producing reaction products to form. But speed loss
would be great. By contrast, in the developer that I proposed, the
diliution is very great, but the tanning action probably helps to
control the contrast. I wish someone would try it out. The films I
would recommend are FP4 or Plus-X,
Bill Troop
>Again, you have two misconceptions: (1) you think HC-110 has a very
>high pH. In reality, it is only half a unit higher than HC-110 --
>barely enough to activate HQ!!!!.
I meant to write, "it is only half a unit higher than D-76."
The pH of HC-110 is 8.8-9.0. The pH of D-76 is 8.5. That is not a very
great difference. Now, the threshold of development pH for
hydroquinone is pH 10 according to M.H. Dickerson (Haist, v. 1, p.
236, fn 84) (Clerc gives 9..5-11). It is therefore simply
inconceivable that HQ is the primary developing agent in HC-110, and
nobody has ever seriously suggested that it could be. An not just for
that reason, but for many others. There is no HQ-only pictorial
contrast film developer.
Dennis O'Connor
change in pH from 8.0 to 9.0 is a change in ion concentration of ten
times... So a change from 8.5 to 8.9 in pH between the two developers means
that one has (roughly) 2.6 times the acid (H+) concentration of the other..
So, as a chemist (in a previous lifetime) I consider that 0.4 pH change
likely to cause a significantchange in the rate of the electrochemical
reactions in the developing tank..
A change of 0.4 pH in your internal chemistry will make you deathly ill, and
some of you won't survive such a change...
Denny
"Bill Troop" <bi...@graphos.org> wrote in message
news:vbf26v845ihfaj92h...@4ax.com...
Bill Troop
<doco...@chartermi.net> wrote:
>The thing you need to keep in mind is that pH is a logarithmic scale... A
>change in pH from 8.0 to 9.0 is a change in ion concentration of ten
>times... So a change from 8.5 to 8.9 in pH between the two developers means
>that one has (roughly) 2.6 times the acid (H+) concentration of the other..
>So, as a chemist (in a previous lifetime) I consider that 0.4 pH change
>likely to cause a significantchange in the rate of the electrochemical
>reactions in the developing tank..
That is an excellent point. We always have to keep in mind that the pH
scale is logarithmic. However, it does not really affect the argument.
All developers ph 9 or lower -- and that comfortably includes
HC-110--are considered 'fine grain developers' in the classification
Haist gives in v.1 p. 349. Anything between pH 8 and 9 is considered,
in photography, to be a "low alkalinity" developer--as opposed to pH
10.5 for carbonate developers and pH 12 for caustic developers. (The
pH of 0.4% sodium hydroxide is 13.)
If I recall correctly, the pH of D-76 can rise from a minimum of about
8.3 to a maximum of about 9.1 upon storage, enough to increase gamma
from 0.78 to 1.19 in about 50 days, according to Carlton and Crabtree
-- but not, necessarily, high enough to activate the hydroquinone to
any significant extent. According Crabtree and Matthews (PCS) borax
developers have a pH range of 8.0 to 9.0; Kodalk developers range from
9.0 to 10.0; carbonate 9..5 to 10.5; caustic soda 11.0 to 12.0 or
higher.
It must be clear by now that Hydroquinone is an inactive developing
agent at the pH of HC-110. Its sole purpose is to energize and
regenerate the phenidone derivative.
The most signfiicant error in John's argument was that he assumed that
HC-110 was a "strongly alkaline" developer without first measuring the
pH or by simply checking the MSDS. For the record, "strongly alkaline"
in photography means at least 10.5. That is not arguable. (Personally,
I would reserve that characterization for a developer above pH 11.)
There is nothing to suggest that hydroquinone can by itself be a
viable developer at anything under pH 10. The use of the organic
amines at their relatively low pH is not sufficient to make HQ active
at that pH. What the organic amines do is to make the PQ combination
much more active than would be expected at the target pH --
essentially, 100 times more active than would be expected. That is a
very notable achievement.
As Crabtree and Matthews point out, the use of organic amines has been
known since the early 1930s, but even on the films of that day,
dichroic fog was too high to make them generally useful. Nor were any
of the earlier antistain agents effective. HC-110's PVP was the
breakthrough.
I myself would not consider using organic amines unless common
developing agents became so rare and so expensive that it was
necessary to conserve them better. I don't consider the results in
negative development to be worthwhile. On the other hand, I can't help
wondering if they couldn't be useful in concentrated print developers.
Nevertheless, given the numerous problems Kodak has had with this
product over the years, it is not very tempting.
Michael A. Covington
>
> I myself would not consider using organic amines unless common
> developing agents became so rare and so expensive that it was
> necessary to conserve them better. I don't consider the results in
> negative development to be worthwhile. On the other hand, I can't help
> wondering if they couldn't be useful in concentrated print developers.
> Nevertheless, given the numerous problems Kodak has had with this
> product over the years, it is not very tempting.
Problems with HC-110? Tell us more. I have always found it very reliable.
John
Myself as well. It's incredibly robust in concentrate and I never had any
"surprises" from it as I did with Xtol.
Bill Troop
>>Problems with HC-110? Tell us more. I have always found it very reliable.
>>
>
> Myself as well. It's incredibly robust in concentrate and I never had any
>"surprises" from it as I did with Xtol.
The problems have been with the manufacturing. Fortunately, users have
not been exposed to this--to the extent that it has always developed
film. However, the characteristics have changed slightly over the
years, as the chemicals have had to be changed. But I can't think of a
commercial formula that has given so much trouble to the manufacturer
over the years. So often, a formula only works just right with
chemicals from a given supplier. Sometimes, one discovers upon moving
to a purer grade of a chemical, that it was impurities in the previous
grade that were making the formula 'work'. Because of its exotic
chemicals, HC-110 has had more than its share of reformulations.
I should have been more explicit. The chemistry is unattractive to me
from a manufacturing point of view. But for that matter, anything with
phenidone is unattractive to me, and I have always disliked the
organic amines. Today, manufacturers have huge problems getting
reliable qualities of potassium bromide, sodium sulfite, and sodium
carbonate, without getting into the variable quality of developing
agents whose consistency we have for so long taken for granted. When
you have to rely on outside suppliers for the chemicals needed for
HC-110, you're in a much more vulnerable position.
It's not just Kodak that has these problems. Some of the formulas from
the smaller manufacturers are surprisingly difficult to manufacture,
and some are surprisingly sophisticated.
I like really, really simple formulas. I believe that everything you
need to do in photochemistry can be accomplished really simply. I know
that's kind of boring to talk about.
I still wonder if anyone really knows for sure what all of the
problems with XTOL are? My own view is that I would never formulate a
commercial product with phenidone without putting in some metol, or
something else, to take up the slack just in case the phenidone (or
phenidone dervative) bombed out.
Has anyone had any experience with FX 50 yet? I talked with Crawley
some ago when he was formulating it, and he was having problems, but
he expected to be able to solve them, and apparently has. He was very
enthusiastic about ascorbates. Isn't FX 50 a two-solution? But I doubt
it will ever get the huge amount of exposure that XTOL did.
I would still enthuasiastically recommend XTOL as long as (1) you
either test with paper before each developing session or (2) you mix
it up from your own chemicals according to a substitute approximation,
like Paul Lewis's Mytol. As I understand it, the results from Mytol
are not substantially different from those in XTOL.
Bill Troop
look at the MSDS for Rodinal Special :
pH is 10.3 (as opposed to 14 for Rodinal)
primary alkali is Triethanolamine at 30-40%
HQ is 1-5%
MISSING: (1) the primary developing agent; (2) the antistain agent
The restrainer is Kbr. The greatest probability is that the primary
developing agent is Phen B or Dimezone, but it could be plenty of
other things. I would not want to guess how effective Kbr might be at
for phen/Dimezone at pH 10.3. Of course, there may be other
antifoggants as well and Crawley has sometimes used both organic and
inorganic antifoggants in a developer -- and not necessarily just to
suppress fog. They all have other effects as well.
In that it uses organic amines, HQ, and is highly concentrated, this
developer is similar to HC-110. But what on earth is the antistain
agent? I supppose it could be PVP, just as in HC-110, since the patent
has expired by now. But Agfa could easily have come up with something
else.
One thing you can be sure of: there _is_ an antistain agent.
Oh yes: and you can be sure that the MSDS is perfectly legal!
Rich Shepard
> pH is 10.3 (as opposed to 14 for Rodinal)
^^
Ouch! That will dissolve living tissue -- such as fingers. That's as
strong a base as there is. Highly dangerous if the pH is 14.0.
Rich
Dr. Richard B. Shepard, President
Applied Ecosystem Services, Inc. (TM)
2404 SW 22nd Street | Troutdale, OR 97060-1247 | U.S.A.
+ 1 503-667-4517 (voice) | + 1 503-667-8863 (fax) | rshe...@appl-ecosys.com
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Dan Quinn
"...if the pH is 14.0." Near that I'd say. It uses KOH as the
alkaline activator. That is part of it's problem when used with Kodak
Tech. Pan. It's a concentrate used at dilutions of 1 + 25 - 200.
Jobo, Tech. Pan., and Rodinal don't go well togeather. Dan
Dennis O'Connor
skin, but if I have a tiny cut on a finger it will find it - right now...
I am, careful with the stock solution as a significant concentration of lye
is present...
Denny
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