Divided developer questions

[justpete]

Pete;

Make sure that the pH values are the same. It should be adjusted to about 10.1 for both solutions. That way you get the best from both buffers for the comparison.

PE

Will do, thanks. I'd initially intended to try them out as unadulterated solutions of roughly the same concentration as the 6% borax solution that is the Formulary's DD-76 bath B. But with a bit of Arm&Hammer and some boric acid both can be adjusted downward until the pH (crudely measured) is about ten, no problem. I'm pretty sure some boric acid from the drugstore is going to work just as well as some from PF as will the bicarb in a box of A&H.

At 5% by weight, going by the data in the borax datasheet from borax.com pH of the 'unbuffered' solutions should be close at about 11.4-11.6, is this about where you start prior to adding their conjugates?

Tnx,
Pete

 

[Photo Engineer]

Pete;

I honestly don't remember. Lately, all of my work has been carbonate and TEA.

PE

 

[sanking]

The logrithmic (sp?) pH scale seems to have very little real world influence in a DD. I have gotten good negatives with a Bath B of 9.5, and also 11. Of far more importance, I've found, is the concentration of developers in Bath A.

Although I have not carried out extensive tests in this area my own experience agrees with Paul's observation in that the major criteria in determining the potential maximum contrast with a DD is the concentration of Bath A, assuming all other factors are equal.

However, in addition to the concentration of Bath A its temperature is also very important because how much the gelatin swells determines how much of the reducer the emulsion can soak up in a given time. Film will soak up a lot more of the reducer in five minutes if the solution is at 80F than if at 60F.
You could also force the film to soak up more reducer by pre-soaking at an even higher temperature, thus selling the gelatin even more.

Sandy King

 

[Photo Engineer]

Sandy;

Using a bath "B" of 50 g/l Tri Sodium Phosphate will boost contrast considerably all else being equal!

PE

 

[sanking]

Ron, I agree with you, if the time of development is the same for TSP as for metaborate.

However, if development is allowed to go on to completion my opinion is that the final contrast will be about the same with metaborate as with TSP, assuming that the reducers used work within the pH range of metaborate. Ultimately the final contrast is determined primarily by how much reducer is in the emulsion.

Please note that this is an opinion, not a statement of fact. I simply have not carried out the requisite testing to speak with authority.

Sandy

Sandy;

Using a bath "B" of 50 g/l Tri Sodium Phosphate will boost contrast considerably all else being equal!

PE

 

[Photo Engineer]

Since this is a development to exhaustion situation, you are right.

However, my opinion is that if you do as you say, the fog will be high. IDK, but I remember Grant Haist saying "If the fog is too high, the pH is too high", or some such and that will be the case here. The E6 color developer uses this, in part, to achieve the total development to completion of E6 films, and Kodachrome does the same. High pH, high fog!

I never did the develop to exhaustion experiment, I just did the develop normally conditions to get the same speed and fog. In that case, the higher pH DD produced higher contrast.

PE

 

[sanking]

Ron,

I am sure that you are right about the B+F. One of the characteristics of Diafine and some other DDs that I have tried is higher B+F than with traditional development.

However, I got involved in two-bath developers from the perspective of a development strategy for a hybrid work flow where the negatives would be scanned and the files then either printed digitally and printed as digital negatives for hybrid wet-processing work flow. When that is the case the small additional B+F that results from DD is not significant.

Sandy

Since this is a development to exhaustion situation, you are right.

However, my opinion is that if you do as you say, the fog will be high. IDK, but I remember Grant Haist saying "If the fog is too high, the pH is too high", or some such and that will be the case here. The E6 color developer uses this, in part, to achieve the total development to completion of E6 films, and Kodachrome does the same. High pH, high fog!

I never did the develop to exhaustion experiment, I just did the develop normally conditions to get the same speed and fog. In that case, the higher pH DD produced higher contrast.

PE

 

[dancqu]

Using a bath "B" of 50 g/l Tri Sodium Phosphate will
boost contrast considerably all else being equal! PE

How about a carbonated glycin only A bath and a
TSP B bath? Two or three minutes at high ph then
that much or more at even higher ph. Perhaps today's
hardend emulsions may not react much to that high
ph pre-treatment.

Could there be such a thing as a Glycin only divided
developer? Dan

 

[sanking]

Why not?

But what would that improve, either in image quality or versatility, over a developer like divided D-23?

Sandy King

How about a carbonated glycin only A bath and a
TSP B bath? Two or three minutes at high ph then
that much or more at even higher ph. Perhaps today's
hardend emulsions may not react much to that high
ph pre-treatment.

Could there be such a thing as a Glycin only divided
developer? Dan

 

[Paul Verizzo]

Thanks, Sandy, for your observations. One of the pertinent phrases of mine that may have been overlooked in this thread is time in Bath B as needed for completion. After that, grain starts developing, not image!

The Otha Spencer two bath that I've mentioned from time to time on this forum, I have since discovered that it is based on, and close to, the Shipman two bath from way, way, back. Sort of a DK-50 with more metol and Q, then a high pH Bath B. Ninety grams of carbonate, that is probably up about 10.8 pH. With only two minutes in either Bath, the negs are very fine grain.

Second, I think that while the temperature of a "non-developing" Bath A will have some effect as you describe, I doubt if it is much. That's just a guess.

 

[Photo Engineer]

Plain carbonated glycin may not keep well enough for you.

PE

 

[sanking]

Paul,

Yes, I don't know for certain about this as I have not done the tests. However, based on my experience with sensitizing carbon tissue I am inclined to believe that the amount of reducer that could be absorbed by most films would increase significantly with temperature, and/or with a pre-soak in hot water.

At some point I will surely test this, if someone else does not beat me to it.


Sandy

Second, I think that while the temperature of a "non-developing" Bath A will have some effect as you describe, I doubt if it is much. That's just a guess.

 

[Photo Engineer]

Swell and diffusion vary as a function of temperature. This is related in two equations at EK, one developed by R. Willis and the other by K. Liang. IDK if they are published, but the data would indicate that the amount of "A" sucked up increases as temperature increases.

PE

 

[sanking]

Ron,

My experience in sensitizing carbon tissue absolutely agree with the research cited. An increase in temperature of five degrees F or more, with the same time of sensitizing, gives a significant boost in sensitivity.

Based on my experience with carbon tissue emulsions there is absolutely no question in my mind but that the amount of reducer that can be absorbed by the emulsion increases with temperature, and by a very significant amount at that.

Sandy King

Swell and diffusion vary as a function of temperature. This is related in two equations at EK, one developed by R. Willis and the other by K. Liang. IDK if they are published, but the data would indicate that the amount of "A" sucked up increases as temperature increases.

PE

 

[Photo Engineer]

I'm glad to hear that Kai Liang and Roland Willis were right then. Our whole diffusion transfer product line was based on their work.

PE

 

[dancqu]

...there is absolutely no question in my mind but that
the amount of reducer that can be absorbed by the
emulsion increases with temperature...Sandy King

Also by an increase in ph. So, the reason for the glycin
A bath. Glycin is moderately active with carbonate. The
high ph will swell the gelatin while development will be
minimal. After A a TSP B bath to kick that glycin
into high gear. A carbonated metol A bath
would be to active. So no D-23.

At a higher temperature and/or ph emulsions have
a greater volume. Dan

 

[Alan Johnson]

As well as glycin perhaps high pH Ascorbate could be tried.

I measured the amount of carry-over from bath A to bath B on the surface of the film, reel and tank,it is about 20ml. When 20 ml of Thornton's A solution was put in part B, the part B alone slowly developed a film put in it,producing a faint visible image after 4 mins. Only one test, but it suggests the B bath may not exhaust but development just becomes very slow after the developer in the emulsion is used up, there being some developer still present in the solution from the carry-over.

 

[Photo Engineer]

Any alkaline bath with a developing agent will initiate the beginnings of development and will thereby increase the effect of any DD.

PE

 

[Paul Verizzo]

Any alkaline bath with a developing agent will initiate the beginnings of development and will thereby increase the effect of any DD.

PE

That's especially true with phenidone, even with only sulfite present, pH will be IIRC, about 9.5. That is, of course, why some formulas lower the pH, slowwwww that development down.

In a phenidone based Bath A of my making with only 30 grams of sulfite, a highly reactive film like Foma 100 is pretty well all developed after 5 minutes! TMY, somewhat. I forget the pH and my notes are elsewhere; probably about 9. Lowering the pH with metabisulfite to 7.6 (handy, that pool test kit) has the TMY making a faint image at 5 minutes. Bueno.

We have to remember, too, that increasing the pH to swell the gelatin also depends on the type of salt used. IIRC, for instance, TSP really opens it up, even adjusted for pH with, say, carbonate. I think part of the reason lies in a sort of osmotic effect even though there isn't a membrane. So, if a lower concentration of a salt can gt the pH wanted, more will enter the emulsion. ??????

Also, thiourea can be used for the same purpose and is not pH sensitive. I've not yet tried it, but am quite tempted.

 

[removed account4]

many moons ago
clay published the formula for mortenson's glycin varient
(there was a url link here which no longer exists)
it is glycin, sodium carbonate and sodium sulfite ( and water ).

it is not divided ...

john

 

[Photo Engineer]

Sodium Sulfide?

PE

 

[removed account4]

Sodium Sulfide?

PE

sorry PE
it was supposed to be sodium sulfite ...

john

 

[justpete]

Any alkaline bath with a developing agent will initiate the beginnings of development and will thereby increase the effect of any DD.

PE

This is what started me wondering about Formulary's DD-76(A) as its pH is 7.5-8.0 but titrating it lower (boric acid? to complement the borax in bath B?) would reduce gelatin swelling and thus reducer absorption. I wonder if the 300mg of KBr doesn't adequately suppress development in bath A though. Obviously I haven't experimented with it yet, just curious as bath A is a MQ variant.

 

[dancqu]

Many moons ago clay published the formula for mortenson's glycin
varient http://www.apug.org/forums/forum37/20714- glycin-fresh-glycin-what-developers-make.html
It is glycin, sodium carbonate and sodium sulfite
It is not divided ... john

Glycin may be THE agent for today's thin emulsion films.
By swelling of the emulsion it's high ph requirement will add
to the emulsion's load of reducer. Two tank processing may
be ideal. The A bath remaining in it's tank should have VERY
long life.

A sulfited, carbonated, A bath and a carbonated
B bath should be worth some one's testing. More
active would be a TSP second bath. Dan

 

[removed account4]

Glycin may be THE agent for today's thin emulsion films.
By swelling of the emulsion it's high ph requirement will add
to the emulsion's load of reducer. Two tank processing may
be ideal. The A bath remaining in it's tank should have VERY
long life.

A sulfited, carbonated, A bath and a carbonated
B bath should be worth some one's testing. More
active would be a TSP second bath. Dan

hi dan

if glycin was human
it would be THE MAN.

foma and neopan LOVE caffenol C and ansco130 (mixed)
they aren't divided .... but if i could find a way ...