Commercial Devs. vs. Custom Chemistry

[gainer]

Take this with a grain of salt, but I seem to recall that pyrogallol was one of the things that I'd heard Europeans complaining was impossible to obtain as an individual. As a manufacturer it might be different, of course. It could be my memory's faulty on this point, though, or I might have been listening to people who were looking for pyrogallol in all the wrong places.

I suppose one of our more intelligent beaurocrats might know that the prefix "pyro" refers to "fire" and think pyrogallol and pyrocatechol are used to make explosives. With our luck, that one will be in charge.

 

[dancqu]

... the book calls for plain hypo and Looten's Acid Hypo ...

Plain hypo is a breeze. On an 8 X 10 basis use 6ml
of A. Thio. or 6gr of S. Thio. anhydrous for a solution
volume of 250ml. Use one-shot with continuous agitation
as the fix is very dilute. So dilute in fact and the volume
so great that a single fix does yield archival results.
Skip the stop.

I agitate by pulling the print in a folding manner upon
itself from the far end then in the same manner from the
side. The print will alternate face up, face down. Two to
four minutes will do S. or A. Thio.

I achieve ZERO stain results with RC in two minutes
when tested for silver using the sulfide test. Establish
times for each paper. Do test for silver. Papers vary.
When toning Zero stain results are needed. Dan

 

[Photo Engineer]

Well, since we are talking about fixers, I won't start a new thread for this. I was looking for a non hardening fixer to use for toning. I was going through the "Darkroom Cookbook" and noticed something that confuses me. Does someone sell sodium thiosulfate in liquid form? The places I have book marked has it as a solid sold by the pound, but the book calls for plain hypo and Looten's Acid Hypo to be made with 16 fl oz. of sodium thiosulfate. I'm open to formulas here. Hmm... just noticed the metric equivelant is in grams, so maybe a misprint? The fl should not be there?

Out, I slipped a cog here. You are quoting from Anchell, and I was thinking Anchell and Troop. Of course, errata for A will not be on the A&T web site suported by Bill Troop. My apologies to all three of you.

I hope that you can get it cleared up.

PE

 

[nworth]

...

MikeS, Dektol is D72 (or D52 - I can never remember which one it is either and I'm too lazy to go to my index of formulas). You guys should remember that a published formula is almost exactly what the plant formula is, with just a few exceptions.

...
PE

Sorry, I'm a bit behind in my reading.

Dektol and D-72 are actually quite different developers. See the MSDS for Dektol. Dektol is compounded to give results very similar to D-72 but to still be sold in single package containers and have long unopened shelf life.

 

[Photo Engineer]

Sorry, I'm a bit behind in my reading.

Dektol and D-72 are actually quite different developers. See the MSDS for Dektol. Dektol is compounded to give results very similar to D-72 but to still be sold in single package containers and have long unopened shelf life.

Exactly how does the MSDS here for Dektol powder -

http://www.kodak.com/eknec/PageQuer...003=*&C013=&C014=Dektol&C901=Z_WEBEXT&x=0&y=0

in any way differ from D72?

The formulas are, for all practical purposes, identical except as I noted above.

PE

 

[Tom Hoskinson]

Well, since we are talking about fixers, I won't start a new thread for this. I was looking for a non hardening fixer to use for toning. I was going through the "Darkroom Cookbook" and noticed something that confuses me. Does someone sell sodium thiosulfate in liquid form? The places I have book marked has it as a solid sold by the pound, but the book calls for plain hypo and Looten's Acid Hypo to be made with 16 fl oz. of sodium thiosulfate. I'm open to formulas here. Hmm... just noticed the metric equivelant is in grams, so maybe a misprint? The fl should not be there?

My copy of Anchell's "The Darkroom Cookbook" (1994 edition) lists the recipe for Looten's Acid Hypo as:

Water (125 deg F/52 deg C)--------------2.0 liters
Sodium thiosulfate (hypo)----------------480.0 grams
Sodium bisulfate--------------------------45.0 grams

That clears up the 16 fl oz. of hypo business, but raises a new question:
Why is Sodium bisulfate called out rather than Sodium bisulfite??

Kodak F-24 and Agfa 300 are both non-hardening fixers that are based on the combination of Sodium thiosulfate and Sodium bisulfite.

Michael A. Smith's Fixer formula is very similar and calls out 25 grams of Sodium bisulfite per half gallon of hypo fixer stock solution. This will result in a much less acidic solution than Anchell's version of the Looten recipe (above).

Michael A. Smith's hypo stock solution is 32 ounces (~960 grams) of Sodium Thiosulfate Prismatic Rice Crystals per gallon of water.

 

[Photo Engineer]

I think that the dialog here only points out one of the problems with hand mixes from the literature.

Unless you go back to original sources (for example the Kodak formula handbook that they used to publish), the literature is filled with typographical errors. It seems that everywhere I turn, I find a formula for a popular developer or fixer that is slightly off or really way out there.

This is a major problem that we must all recognize and work towards fixing up.

Sodium Bisulfate and Sodium Bisulfite are two very very different compounds and will give drastically different results. One has a bi-SULFATE (HSO4) radical and the other has a bi-SULFITE (HSO3) radical in it. The Sulfate is essentially neutral in reactivity and pH, the Sulfite is a mild reducing agent and is slightly more alkaline in solution. The bi-Sulfite gradually turns into Sulfate and bi-Sulfate via oxidation in solution. Sulfite (bi-Sulfite) offers protection to the hypo, but Sulfate (bi-Sulfate) offers none.

This is a drastic simplification of the chemistry and equillibria involved.

PE

 

[sanking]

There is no question but that typographical errors are a major problem in the literature, and you can find at least one or two in even well written and edited books.

One will also find numerous variations on formulas, especially developers, and this can be confusing for people who don't understand how the various chemicals in a particular formula work. And you find this even in variations of very popular formulas such as D76. What exactly is D76? If you mix it without hydroquinone, one of the variations proposed in The Film Developing Cookbook, does it give the same results in all conditions as the original formula?

Sometimes the variations don't make a lot of difference in practice, but at other times even minute changes in the amount of some of the chemicals will result in a dramatic difference in the energy of the developer, as well as grain and sharpness.

Sandy

I think that the dialog here only points out one of the problems with hand mixes from the literature.

Unless you go back to original sources (for example the Kodak formula handbook that they used to publish), the literature is filled with typographical errors. It seems that everywhere I turn, I find a formula for a popular developer or fixer that is slightly off or really way out there.

This is a major problem that we must all recognize and work towards fixing up.

PE

 

[Ryuji]

D-76 without hydroquinone has lower poorer keeping properties and it is less suitable for long term keeping. The reason is that, Metol and hydroquinone have mutual inhibition of aerial oxidation reaction. (Sulfite is also involved in this.) There is optimal ratio in M and Q that minimizes oxidation as a whole. Of course there are other ways to deal with this problem other than adding hydroquinone, but what I'm saying is that simple removal of hydroquinone has this kind of effect.

However, if you mix immediately before use, especially for one-shot or limited replenishing method, D-76 without hydroquinone is quite practical.

Sometimes the variations don't make a lot of difference in practice, but at other times even minute changes in the amount of some of the chemicals will result in a dramatic difference in the energy of the developer, as well as grain and sharpness.

Commercial products rarely adapt such formulae that have great sensitivity to slight variations for obvious reasons. Good formulators usually try to come up with a way to achieve the same goal with less error-sensitive ways, though this may not be always possible.

But another thing is that, film emulsions are also different among current lines, as well as current films compared to ones from 1970s. Modern emulsions are a lot more closely designed and manufactured with tight control, while old emulsions are more ad hoc. For example, most negative emulsions produced today have 3+ emulsions blended. (in color negatives, 3+ emulsions blended in each color layer.) One emulsion largely covering the toe region, another in highlight region. But the one covering the toe region itself may be a blend. Same for the emulsion covering the highlight region. Manufacturers usually design those emulsions to develop together very similarly in the same developer, but other times they intentionally do otherwise. A good example might be T-MAX P3200, Delta 3200, and Neopan 1600. By giving slightly different developer reaction in the toe and highlight regions, they can make more graceful results when the film is pushed.

So, a trick that works on APX25 should work for TMZ? I don't know. What about trick that worked with Panatomic-X, is it goign to work with Pan F Plus? These are legitimate questions no matter which developer is used, but it is more serious with developers that are sensitive to slight difference in ingredients.

Also, with highly optimized emulsions, achievable effects significantly different from "standard result" are at sharp trade off with loss of quality in other aspects of the image quality.

The picture may be a bit different for those who work with low tech films from Eastern Europe, though.

 

[dancqu]

One has a bi-SULFATE (HSO4) radical and the other
has a bi-SULFITE (HSO3) radical in it. The Sulfate is
essentially neutral in reactivity and pH, the Sulfite is
a mild reducing agent and is slightly more alkaline
in solution.

I'm sure you must have some other chemicals in mind.
As is somewhat commonly known a bisulfate can be
used as a substitute for sulfuric acid.

A bisulfite solution is acid: ph 3 - 4. I've not made
an exact determination. Patrick Dignan recommends
stock solutions of phenidone in bisulfite solution. "The
acid condition of the above solution improves
the keeping properties ... ".

Formula: 1 gram phenidone and 5 grams sodium
bisulfite. Water to make 1 liter.

From another source I've read that such a solution
will keep phenidone in good shape for several months.
It should. The solution is both acid and contains a
preferential oxygen scavenger. Dan

 

[Photo Engineer]

Dan, you are absolutely right. Where was my mind. I was thinking sulfate and sulfite, when writing about bi-sulfate and bi-sulfite. AAAGH.

So sorry all. Both the bisulfite and bisulfate are acids, the sulfite is slightly alkaline and the sulfate is neutral.

None of the four can be effectively substituted for the other without either an activity change or a pH change in the photographic solution where used. Sulfite and bisulfite are preservatives and silver halide solvents (used in fix baths as preservative and D76 as both preservative and silver halide solvent for example) and the sulfate and bisulfate are used as pH buffers on the acid side in fix baths. Without sulfite or bisulfite, a fixer becomes less stable especially on the acid side. So, I suspect that a bisufate containing fix with no bisulfite or sulfite will sulfurize rather rapidly.

It goes to illustrate that formulas are often not recorded correctly even with the best intentions. It also brings up the question of what the bisulfate is doing in that fix, as it might cause it to become too acidic and bring about decomposition due to acid content and lack of sulfite ion as a preservative.

Both fixers and developers use sulfite ion as a preservative.

Thank you for catching me. It helped emphasize my point though, and I didn't even do it on purpose. Honest.

PE

 

[MurrayMinchin]

What are the potential benefits of mixing one's own chemistry vs. using these commercial developers?

There appears to be a fair bit of "wiggle room" on this thread so;

Make a print with Kodak Selectol Soft. Make a print of the same image with Ansco 120. Compare.

That's why you mix your own

Murray

 

[Tom Hoskinson]

What Murray said!

Kodak D-52 Paper Developer
Water (125 deg F)---------------------500 ml
Kodak Elon (Metol)--------------------1.5 grams
Sodium Sulfite (Anhydrous)-----------22.5 grams
Hydroquinone-------------------------6.3 grams
Sodium Carbonate (Anhydrous)-------15.0 grams
Potassium Bromide (KBr)---------------1.5 grams
Water to make------------------------1.0 liter
Note: For warmer tones, add more KBr



Ansco 120 Soft Working Paper Developer
Water (125 deg F)--------------------750 ml
Kodak Elon (Metol)--------------------12.3 grams
Sodium Sulfite (Anhydrous)------------36.0 grams
Sodium Carbonate (Anhydrous)--------36.0 grams
Potassium Bromide (KBr)----------------1.8 grams
Water to make-------------------------1.0 liter
Note: For warmer tones, add more KBr

Compare this Ansco (Agfa) developer with Kodak D-52

Ansco 135 Warm Toned Paper Developer
Water (125 deg F)---------------------500 ml
Kodak Elon (Metol)---------------------1.6 grams
Sodium Sulfite (Anhydrous)------------24.0 grams
Hydroquinone--------------------------6.6 grams
Sodium Carbonate (Anhydrous)--------24.0 grams
Potassium Bromide (KBr)----------------2.8 grams
Water to make-------------------------1.0 liter
Note: For warmer tones, add more KBr

 

[MikeS]

Sodium Bisulfate and Sodium Bisulfite are two very very different compounds and will give drastically different results.

I recall reading somewhere (was it here on APUG?) that Sodium Bisulfite is used in swimming pools to decrease the pH. Armed with this knowledge I went out, and bought a 5lb bottle of the stuff, and I checked in the store, yup, it's Sodium Bisulfate, just like they said it would be! Well, it's not till I get home, and recheck my info, and the bottle label that I realize I now have 5lbs of bisulfAte, not bisulfIte!!

So, other than decreasing the pH of my non-existent pool, is there anything I can actually do with this stuff in a photographic formula?

Thanks.

-Mike

 

[Ryuji]

So, other than decreasing the pH of my non-existent pool, is there anything I can actually do with this stuff in a photographic formula?

One thing I can think of is... to replenish exhausted stop bath. If you use indicator stop bath, it's pretty easy. When you see the solution turning purple, add bisulfate until the solution comes back clear yellow. That's that.

 

[Photo Engineer]

Tom, that listing of paper developer formulas is interesting.

It shows the apparent tolerance available to the hobbyist mixing the chemistry - something noted here in posts. It also mentions the change in image tone. So, the final results across those developers may be the same for speed and contrast but may differ quite a bit in image tone.

I'm sure we would also find that the rate of development varied, and the response across paper types was not necessarily uniform.

In other words, we can get usable and in fact, good results from all of them, but to a critical eye, each of them would differ. If you mixed one up and used it today, then re-mixed it tomorrow with a 10% error in bromide, would you worry about image tone changing? Would you worry about a 2" in 12" change in exposure time? I'm not sure most out there would be overly concerned.

Just another point in this argument. It depends on what you expect and what you are doing. Some people would be satisfied, and others would not. It boils down to a matter of opinion.

PE

 

[gainer]

Maybe this summarizes a lot of what has been posted: If you think you will have fun mixing and perhaps even modifying recipes from old or new books, try it but don't expect to get it right the first time. What you may learn from the first time is whether it's worth a second try. Even if your recipe gives recommended development conditions, they may aply to older films that have been changed a great deal in the meantime. (The first instructions that came with Kodak D-76 said to do Super-XX for 17 minutes at 68 F. with full strength soup.) Use the highest grade of chemicals you can get for first tries. Later, you can experiment to see how far you can stray. It's never good to experiment with important pictures. A test roll to gain knowledge is never wasted.

 

[nworth]

Exactly how does the MSDS here for Dektol powder -

http://www.kodak.com/eknec/PageQuer...003=*&C013=&C014=Dektol&C901=Z_WEBEXT&x=0&y=0

in any way differ from D72?

The formulas are, for all practical purposes, identical except as I noted above.

PE

I checked your reference, and you're right. Except for the Calgon and the coating to make the metol dissolve (not noted in the MSDS), they appear to be similar. My remark was based on looking at the package and MSDS a couple of years ago. At that time, Dektol used a different developing agent and used TSP as the alkali. Proprietary formulas do change from time to time.

 

[Photo Engineer]

Nworth, the TSP was not the alkali. If they used TSP for alkali, the pictures would end up looking like Kodalith prints. The pH would be too high and so would the contrast as a result.

The TSP was a substitute for Calgon and was actually in quite low concentration.

Back a few years ago, Calgon changed their formula from a phosphate to something else less effective for EK purposes (still a good product, but not for photo use - this goes to the photograde designation discussed here as well). EK changed to a TSP derivative as sequestrant, and finally ended up using Quadrofos. Try looking it up on the internet and you will find the product still listed.

In any event, the MSDS can be quite misleading. It is not intended to give you a method to replicate the formula. It is there for safety.

PE

 

[Gerald Koch]

At that time, Dektol used a different developing agent and used TSP as the alkali. Proprietary formulas do change from time to time.

If you are referring to bis (4-hydroxy-N-methylanilinium) sulfate vs p-methylaminophenol sulfate being mentioned in the MSDS it is because they are the same developing agent. They both have the same CAS number (55-55-0) and are thus the same chemical. I don't know why Kodak did this except to confuse people. Other than minor and functionally neutral changes, the formulation for Dektol has remained unchanged from its inception.

 

[nworth]

If you are referring to bis (4-hydroxy-N-methylanilinium) sulfate vs p-methylaminophenol sulfate being mentioned in the MSDS it is because they are the same developing agent. They both have the same CAS number (55-55-0) and are thus the same chemical. I don't know why Kodak did this except to confuse people. Other than minor and functionally neutral changes, the formulation for Dektol has remained unchanged from its inception.

That, I knew. I think they use that name because it is the formal name for the chemical required in some countries. No, Dektol was really different for a while.

 

[gainer]

I hear that Kodak used catechol in HC110 for a while. If they had a surplus on hand or a cheap source for it, why not? Catechol and hydroquinone are not so much different in many uses. Both will stain in low or no sulfite developers, but it doesn't take much sulfite to prevent staining.

What other agent than phenidone would be likely to be used in place of metol? Maybe p-aminophenol? I'll have to try that sometime.

 

[Tom Hoskinson]

That, I knew. I think they use that name because it is the formal name for the chemical required in some countries. No, Dektol was really different for a while.

Different in what way?

 

[Photo Engineer]

So many rumors abound, but AFAIK, no one knows the 'truth'.

EK does not and cannot change formulas on a whim. It takes $$$ to do the R&D to prove conclusively that a formula change will not hurt the customer in any way. Spending $$$ reduces profit. So, formulas rarely change, and only change for a good reason.

Along with all of the tests are toxicity tests and shelf life which take quite a while to accomplish.

The only change I ever heard of in my time working there was one in B&W and color products from Calgon to Quadrofos, and some technical (methodology) improvements in mixing and packaging.

In color, they changed from hydroxylamine to diethyl hydroxyl amine in some developers. Another minor change. They went to a sulfite adduct of the developing agent in the color developer.

HC110 went through some revisions at the startup as did several of the newer liquid kit products. I am not aware of the changes in these formulas, but I understand that they were minor as well.

PE