Experiences with Vitamin C developers please

[mrred]

In my early years, I used to be a radio / tv tech. I remember RCA (late 70's early 80s) made, without question, the best quality TVs. They did this by designing the circuits around specific qualities of the components. When one would fail, substitutions could not be made without a significant loss of quality. Other manufacturers tended to design generically and could easily adapt to substitutions.

Jay did confess the assumptions of good quality ingredients to make his 510-Pyro to work. Other recipes design allow for some deviance. let's just not throw out the baby with the bath water.

 

[rbultman]

let's just not throw out the baby with the bath water.

Roger that. I'm intrigued by many of the developer formulas that have been published. I fully intend to devote more time to pursuing that end of the hobby once I have a little more time on my hands. But, it is definitely lower on the priority list than learning how to print.

Sent from my Nexus 5 using Tapatalk

 

[Gerald C Koch]

But the worm died happy.

 

[stormpetrel]

I have followed this thread with interest and I would like to share my last tests with your regarding home brewed vitamine C developers

https://flic.kr/p/s6ELV8 by stormpetrel_geek_mode, on Flickr


Pyro 510
--------

I have tested my bottle of 510-pyro following the recommendation of PE (develop a piece of exposed film in daylight and simply check that it is properly developed within the recommended time). This is a simple test but very useful indeed. I wonder why I did not do this kind of test before.... Thank you PE!

My bottle of 510-pyro is 2 years and half old and the results were just as expected which confirms the long shelf life of this kind of developer.

HP5+ 7m10 @ 20°C, 1+100

My first try was with dew point water. The pH was unsurprisingly quite acid (pH 6.1) but once mixed with 510-pyro, the pH jumped to 8.9 which is the expected value for this kind of TEA developer.

My pyro-510 was prepared as follow:
Heat the TEA in a pyrex recipient up to 150°C (not in a microwave as you can not control the temperature this way but on a stove with a thermometer)
Add the ascorbic acid which dissolves quite rapidly with then the Pyrogallol which too dissolves quite rapidly.
Then add the Phenidone. Stir until all of the chemicals have dissolved (with a magnetic stirrer as it is quite long to dissolve)

TEA (triethanolamine) 75ml (99% pure, brand Roth,)
Ascorbic acid 5g (L-ascorbic acid not the sodium ascorbate, trademe.co.nz, our national ebay)
Pyrogallol 10 g (from artcraft.com, USA)
Phenidone 0.25 g (from disactis.com, France)
Complete up to 100ml

I did a second test with tap water (pH 7.3). Once the 510-pyro diluted at 1+100, the pH rised up to 8.8.
The results were similar to the first one
The two pieces of cut sheet film, once developed were very dark with a distinct brown stain but slightly less dark than those developed with PC-Tea and Pa-rodinal. This is expected for pyro developer


PC-Tea
--------

The PC-tea is very similar to 510-pyro except it does not contain any staining agent but it is as dark as 510-pyro
I used the same chemicals as those one listed above and I prepared the developer in the same way I prepared the 510-pyro (@ 150°C)

TEA (triethanolamine) 99% 75ml
Ascorbic acid 9g
Phenidone 0.25g
Complete with TEA up to 100ml

This batch of PC-Tea is just 1.5 year old...

I did the test with tap water. Once diluted the pH reached 8.8.
I have developed the piece of HP5+ at 9min @ 22°C 1+50
The piece of film once developed was perfectly dark.


Pa-Rodinal
----------

Used as reference.
I prepared it from paracetamol powder 2.5 years ago and yes, it still works like a charm as Rodinal does.
Got exactly the same results as the PC-Tea.


Conclusion. No problem to report with those developers, they work as they should and they have an impressive shelf life.


PS: pH were measured with a properly calibrated pH meter

 

[sfaber17]

Here are results of my 510 Pyro with HP5+ tests with the following updates: 99% TEA from chemistry store instead of 85% from PF, Pyro from PF instead of my homemade Pyro, distilled water instead of tap, kept TEA below 65C when mixing the chemicals, ran the jobo at low 25rpm. This time the stock is clear or slightly yellow instead of fairly dark red. The spent developer is quite oxidized but not totally. The improved developer is more active but the development times are still not close to the massive dev. chart or other reports. However, it seems quite useable. I'm using the 1:30 min water rinse for a stop, and neutral rapid fixer 4min.
Comparing the 510 Pyro at 1:100 with HC110 at 1:63, the HC110 I use at 11 or 12 min 20C for good film speed and gradient similar to another post I saw recently. 510 Pyro at 7.5min 23C G=.47 is close to HC110 at 10 min 20C G=.48. The 510 Pyro at 10min 20-23C G=.58-.62 is pretty close to what I would use, comparable to HC110 11min 20C.
The fog levels are nice and low.

 

[Photo Engineer]

Where are all the results and what did you see?

Also, remember that staining developers have images in the UV which you cannot see.

Tell me (us) more!

PE

 

[Rudeofus]

IIRC, swmcl had no contrast/speed problems with fresh 510 Pyro, but big issues with year old 510 Pyro. I would also assume that 99% TEA creates a less active developer than 85% TEA, because the remaining 15% are mostly DEA and MEA from what I read, and both DEA and MEA are more alkaline than TEA. There is a good chance that the massive dev chart's numbers were determined with developer mixed from 85% TEA.

 

[sfaber17]

Where are all the results and what did you see?

Also, remember that staining developers have images in the UV which you cannot see.

PE

I guess the contrast could be different for the pyro on vc papers. My wife is also saying "when do I get to see a photo?" so I should actually try do a print one of these days.
I'm using enlarger light with the Darkroom Automation meter for a densitometer. It works quite well. I notice a few percent or so increase in contrast measurements if I use cyan light. I think the UV would give around 10% higher contrast.
I want to try tray development and perhaps make some with the 85% TEA to test Rudeofus's theory.

 

[Rudeofus]

I want to try tray development and perhaps make some with the 85% TEA to test Rudeofus's theory.

Since you have a pH meter and both versions of TEA, all you need to do is measure pH of 10ml/l solutions of each. Going from "This has higher pH" to conclude "This will give me a more active developer" should be self explanatory.

 

[mrred]

It's not much of a test, sfaber17. It's the water in the %85 tea that's the problem. It just oxidizes the developer. Don't waste your tea.

 

[Gerald C Koch]

It's not much of a test, sfaber17. It's the water in the %85 tea that's the problem. It just oxidizes the developer. Don't waste your tea.

Actually 85% TEA (technical grade) does not contain 15% water as is sometimes supposed. It contains 15% DEA and MEA as a result of its method of manufacture. The DEA being more basic raises the pH of the mixture above that of pure TEA. Therefore it is very important to use the grade of TEA specified in the formula. Jay deFehr clearly specified the use of 99% TEA in his formula for 51 0-Pyro.

 

[mrred]

Well, that was Jay's explanation why it would prematurely oxidize with the %85. Too bad all his posts are gone.

 

[Alan Johnson]

There are two forms of 85% TEA, both to be avoided if possible in favor of 99%:
http://photo.net/black-and-white-photo-film-processing-forum/00Xr5f

 

[mrred]

Nice to know I wasn't nuts....

 

[Gerald C Koch]

There are two forms of 85% TEA, both to be avoided if possible in favor of 99%:
http://photo.net/black-and-white-photo-film-processing-forum/00Xr5f

Actually the situation is even more complicated than the link would indicate. For photographic use we need to restrict things to TEA 99% and TEA 85% + 15% DEA. This is a further example of why it is important to be specific as to just what is being used in a particular formula. Always read the MSDS that comes with each chemical.

http://www.dow.com/amines/prod/ethano-tea.htm

I was unaware of the adulterated LFG versions containing water to protect from freezing. They were never mentioned in MSDS forms that I consulted. However my apologies to mrred and all.

 

[sfaber17]

Since you have a pH meter and both versions of TEA, all you need to do is measure pH of 10ml/l solutions of each. Going from "This has higher pH" to conclude "This will give me a more active developer" should be self explanatory.

OK, the 99% TEA gave a pH of 9.8, and the 85% with 15% DEA/other non-water forms gave pH=10.2. My meter is a bit drifty and needed a soaking but I think they are about right and illustrate the point. I agree the 85% would be a more active developer, but don't know if it would directly translate to a higher gradient development without testing it because it may cause more aerial oxidation leading to less effective development time.

 

[Photo Engineer]

You must consider that the DEA which raises the pH is only there in 15% concentration which will give it less buffer capacity. This will lower the impact of the impurity.

PE

 

[swmcl]

I am of the opinion after my experience that TEA is a poor ingredient because of the variability in its constituency and because it is not my kind of easy to dispense due to its viscosity. It can be that the pH of the TEA is also not adequate for some developing agents also I believe. I think pyrogallol requires less pH than pyrocatechol and TEA is able to be used with pyrogallol but ...

I am also favouring the idea of a two part developer with the accelerator in part B so that there is more control of the pH independent of the developing agents. I don't understand how a one-part developer can really have its dilution changed dramatically. eg. stand development. When I started out on this journey, I was under the impression that a certain TEA-based developer could be diluted from around 1:100 through to 1:400. This same developer was also long lasting because it was in a TEA base. I realize more testing should be done but I am not of these opinions now.

My thanks go to all those who contributed in this thread. It has been a constructive discussion.

 

[Photo Engineer]

A two part developer has problems of its own. This includes the thickness of the emulsion layer and the amount of Silver Halide present. So a two bath must be optimized for each film you intend to use.

PE

 

[Rudeofus]

PE, I think swmcl referred to a developer mixed from two concentrates, which would give him the option to independently control both development agent concentration and alkalinity. But yes, once you bring developer exhaustion to the table, the amount of developable silver halide may change the outcome.

 

[Photo Engineer]

Sorry for that confusion.

PE

 

[pentaxuser]

Well, that was Jay's explanation why it would prematurely oxidize with the %85. Too bad all his posts are gone.

Who is Jay and why are all his posts gone? Sounds like a pity as they may be germane to the discussion?

Thanks

pentaxuser

 

[Gerald C Koch]

There is nothing wrong with using TEA but you need to know just what you are using. That is why it is important to read the MSDS that should come with this chemical. Agfas Studional contained 30% TEA and was a very nice developer. In fact you should always read the MSDS data for any chemical. For example sodium carbonate comes in an anhydrous form, as monohydrate and as a decahydrate. Using the wrong one will throw off a developer formulation. I mention the decahydrate because I believe that it is still available in the UK as washing soda.

 

[swmcl]

Sorry if this is off topic but I started it !!

Can one or two of the more enlightened ones please make a comment as to the merits of storing developers under CO2 ? Could I have inadvertently lowered my pH significantly of a TEA based single part developer by giving it a squirt of CO2 as I put the lid on ?

I ask this because when I was measuring the pH of my distilled water as part of this discussion I remember the pH wildly fluctuating but starting at around 7.2 and heading down to settle at around 5.6 IIRC. I was using a magnetic stirrer and a beaker with some 300ml of distilled water at the time.

I have since learned that what I saw was quite acceptably explained by the absorption of CO2 from the atmosphere making carbonic (?) acid albeit in an obviously weak concentration.

Now I wonder if the pH of my TEA would be lowered just enough to slow the developer appreciably. (Remember I have tried the developer with a carbonate accelerator which makes for a multicoloured witches brew !)

This might make another reason for mixing the developing agents in glycol which I measured at a pH of 5.5 which couldn't care less about a blanket of CO2 I should imagine...

 

[Rudeofus]

I brought up this "what would CO2 do to TEA?" issue earlier in this thread, but nobody commented on it. I don't have an answer to this, but would be very interested in hearing one. We know that TEA reacts violently with SO2 to form an adduct, but a search for CO2 and TEA came up empty.

Glycol won't save you from these troubles, because you will have to supply some source of alkalinity anyway. If you keep your developer concentrate neutral/acidic, and use a separate concentrate to raise pH, that separate concentrate will have limited lifetime. You can make very long lasting and reliable developer concentrates with DEA and TEA, as exemplified by HC-110.