c vitamin paper developer stock solution life

Hello,

someone among you would know the shelf life of the gainer's PAPER DEVELOPER stock solution? Stored in plastic bellows bottles.

formula:

4 gr c vit
15 gr sodium carb anhydrous
0.5 gr metol
1 gr potassium bromide
WTM 1 LT

Cheers

Not sure about this developer but I do know about Xtol. I find that plastic bellows bottles are not the best for storage. A larger number of small glass bottes with metal lids do a much better job. In general I mix up my Xtol and store it in 330ml glass bottles (used Perrier water bottles). I use one small bottle each time I develop. Xtol lasts for 2 years for me this way.

The longest lasting developer I own is PMK. I'm still using the same batch after 7 years and all is well.

I'm no chemist, so I could be way off base here, but I see that there is no preservative, typically sodium sulfite, in the mix. I'd expect both the metol and the ascorbate to oxidize quickly. Coming from Mr. Gainer, I'd expect that the developer works well, but I don't think it would keep. Probably best to mix it up, use it for a session, then discard.

Mix the C and the Metol ten times stronger in Glycol, that mix lasts for ages since there are no water and is acidic. Then have the carbonate and the bromide in another solution and make a working solution 1:9 when you will use it. You could also make the second solution stronger and then mix 1:1:8 with water upon use.

fschifano said:

I'm no chemist, so I could be way off base here, but I see that there is no preservative

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The vitamin C serves the 'preservative' (aka anti-oxidant) functon. And, being an organic reducing agent also contributes to the development (and possibly also provides metol regeneration). It's a very cute developer.

Part of Patrick's goal was a paper developer without any sulfite, as sulfite is a major cost component of Dektol.

Due to the ready availability of sulfite in the food industry, I doubt if sulfite is a major cost item in developers compared to HQ or other potential ingredients. I believe that this particular developer will have limited shelf life.

It would be nice if we knew the aim pH value.

PE

Photo Engineer said:

Due to the ready availability of sulfite in the food industry, I doubt if sulfite is a major cost item in developers compared to HQ or other potential ingredients. I believe that this particular developer will have limited shelf life.

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FWIW, I did some cost comparisons once, about five years ago. I've still got my spreadsheet with the results. For D-72, the total cost for a liter of stock solution was $1.21. The three most expensive ingredients were hydroquinone ($0.40), metol ($0.30), and sodium sulfite ($0.26). For Dead Link Removed the total cost for one liter was $0.55, with the five priciest ingredients being ascorbic acid ($0.17), sodium sulfite ($0.07), triethanolamine ($0.07), salicylic acid ($0.07), potassium bromide ($0.07), and sodium sulfite ($0.07). FWIW, Dimezone S, the second developing agent, came in at $0.06. DS-14, BTW, is designed to be used with a replenisher. Used that way, it keeps quite well and is economical.

So for paper developers, the sulfite is among the major costs, but probably not the #1 cost or a high enough cost to produce significant overall savings if eliminated. Sulfite is a bigger component of many film developers, though. For D-76, for instance, sulfite is the #1 cost ($0.58 of $0.95), with the #2 being metol ($0.20).

Good figures, but due to the posts above, I would add Ethylene Glycol or Propylene Glycol.

Just to be complete, you may want to indicate price per gram and price per unit quantity used to make a given developer. It is not clear to me exactly how you used your figures. You use a lot more TEA for example, than Sulfite. Another factor is that in spite of using less Bromide as an example, you still have to buy a full bottle of it, usually running up the price when actually calculated.

Thanks.

PE

The ascorbate based Tektol Developer concentrate,once opened,has a life of 6 months.
It is a lot more concentrated than Gainer's formula and contains the antioxidant triethanolamine.
However this shows that ascorbate probably does not hydrolyse particularly rapidly in carbonate solution and a concentrate of Gainer's developer ,in absence of air,might keep for some months.
This is a bit speculative,the data for Tektol is at digitaltruth.com.

Alan;

Triethanolamine is not noted for being an antioxidant! In addition, the original formula for Tektol has been revised to indicate a more stable version and then was replaced with a new generation of products. This should all be considered when making a comment.

Developer development (pun not intended) is a complex science requiring years of study and work. To make a definitive statement one must may hours of tests to prove ones assertions. I have done such tests.

PE

srs5694 said:

many film developers ... For D-76, for instance, sulfite is the #1 cost ($0.58 of $0.95), with the #2 being metol ($0.20).

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Going from memory I think Patrick's no-sulfite Vitamin C developers started with film developers. The paper developer came as a later variant, where the sulfite savings aren't as great. He also has a formula that uses minute amounts of Phenidone in place of Metol, saving more money. For those even more parsimonious one can replace the Phenidone/Metol with left-over coffee, but this doesn't work very well for prints unless one likes a 'very warm' paper base.

PE,

I took the "formula" for Tektol from the MSDS which assume is the current product.
My mistake to say triethanolamine is the anti-oxidant, it is probably some organic which replaced the salicylic acid originally used in DS-14.
But my point was that in Tektol concentrate containing carbonate and ascorbate the ascorbate does not hydrolyse or the concentrate would not last 6 months.
In absence of air would a Gainer carbonate ascorbate concentrate hydrolyse?
It might not or Tektol might have some anti-hydrolysis ingredient, IDK.

mmm...your answers are all interesting..I would like also mr. Gainer say his own comment...

Alan Johnson said:

PE,

I took the "formula" for Tektol from the MSDS which assume is the current product.
My mistake to say triethanolamine is the anti-oxidant, it is probably some organic which replaced the salicylic acid originally used in DS-14.
But my point was that in Tektol concentrate containing carbonate and ascorbate the ascorbate does not hydrolyse or the concentrate would not last 6 months.
In absence of air would a Gainer carbonate ascorbate concentrate hydrolyse?
It might not or Tektol might have some anti-hydrolysis ingredient, IDK.

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If it has water, needed to dissolve the carbonate, then it would likely oxidize slowly. If it is water free, made so by using TEA as alkali, and as noted in other posts, then it would not oxidize very rapidly at all.

PE