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Formulary TEA now 85%

ntenny

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This might be old news, but I just opened a bottle of TEA from the Formulary (bought about a year ago), and the contents were much thinner than past batches. Previously, I’ve found their TEA very difficult to draw into a syringe, and this batch flowed right up, about like the old HC-110 syrup. My ascorbic acid also seemed to dissolve faster in it than I’m used to, but that may be just because the stirrer had an easier time spinning in the thinner medium.

Checking the SDS revealed that the Formulary now list their TEA at 85%, with the rest claimed to be diethanolamine. I’m pretty sure it used to be listed higher. I went ahead and mixed up a batch of PC-TEA as usual, and my test roll looks fine to the eye, but I wonder if there are photographic implications to this change. Has anyone done real testing on developers mixed with 85% TEA vs. higher concentrations?

-NT
 

John Wiegerink

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The viscosity changes with temperature variations also.
 
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ntenny

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John Wiegerink said:
The viscosity changes with temperature variations also.
Click to expand...

True. The temperature in my darkroom is very stable, though, and this is clearly much thinner than the old stuff in an apples-to-apples comparison.

-NT
 

dcy

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Well, I guess I won't be buying my next batch of TEA from PF. I do not have the energy to try and figure out if or how to adjust the PC-TEA recipe or the way I use it in order to compensate for adulterated ingredients. ArtCraft chemicals has TEA.
 

john_s

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Isn't DEA in water more alkaline which would mess up developers relying on TEA for pH level?
 

Alan Johnson

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XTOL patented?

Patrick; The top graph is of binary, not ternary mixtures. I misread the graph and I apologize. This is a plot of the melting point of the 3 Ethanol amines as a function of water content. The second plot is actually a pair and I missed the second plot. You need both to get pH vs...
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Gainer said the commercial version is not necessarily an inferior product. But neither he or Sandy King who seems to have done most of the pH measurements seem to have done any comparison of PC-TEA made with the 99% and commercial grade TEA.
 
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ntenny

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Thanks, that thread is fascinating, albeit not totally conclusive. Putting together tidbits of information from that discussion, I gather the following:
1. DEA should raise the pH of the mixture, hence probably a more active developer;
2. DEA is a stronger silver solvent than TEA;
3. The effect of the DEA mixture on the freezing point is unclear;
4. Pat Gainer mentioned using 99% TEA from the Chemistry Store, so it might be a fair guess that his original recipes were made with that.

I don’t have precision tools for developer testing, so I’m at a bit of a loss. I could toss the batch of developer and order some higher-purity TEA. I could go ahead with what I’ve got on the theory that if I can’t see a putative problem it doesn’t matter. I could take a stab in the dark and cut my developing times a little to try to compensate for expected higher activity. I’m open to thoughts on all of these possibilities.

-NT
 

halfaman

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DEA will not make your TEA thinner. On the contrary, DEA has a higher melting point than TEA and the mixture should be thicker at room temperature. 99% TEA will be thinner than 85% TEA + 15% DEA at room temperature.

And there is another 85% TEA presentation, at least in Europe, that has no DEA but 15% of water...
 

retina_restoration

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Have you messaged PF to ask them about this, and inquire whether or not it has any practical implications? Seems to me that's a good place to start.
 

bluechromis

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Some have suggested that it is the impurities in TEA, rather than the TEA itself, that causes the loss of film speed with PC-TEA. This seems to imply that it is best to obtain the purest possible formulation of TEA.
 
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ntenny

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I just talked to Bud at the Formulary. He said they’ve been drawing from the same giant drum of TEA for the last few years, and he didn’t know a reason for the viscosity to have changed in that time. So I’ve hit a bit of a dead end on that front.

I think I’ll keep working with this batch of developer, since it seems to be working superficially well and I’m not likely to take any photos for which development precision is ultra-critical, and the next time I mix a batch I’ll try preheating the TEA to drive out any water impurity (as someone suggested in the Xtol thread linked above).

-NT
 

retina_restoration

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But the question now is: if PF has been selling the exact same product for years, was that product always 85% TEA? If it's always been 85% TEA, then as far as current buyers are concerned, nothing has changed. If it worked for you last year, the stuff you buy today should be exactly the same.

Here is what I have learned about checking the viability of TEA that has potentially been stored for a long time:

Start with a basic check:
  • Color: Fresh TEA is colorless to very pale yellow.
    Dark yellow, amber, or brown discoloration suggests oxidation.
  • Clarity: It should be clear.
    Cloudiness may indicate contamination or moisture absorption. (It is hygroscopic)
  • Smell: It should have a mild ammonia-like or “chemical” odor.
    Sour, sharp, or rancid odors may indicate breakdown or contamination.

​

2. Simple Solubility Test​

Mix a small sample of your TEA with distilled water at room temperature (1:1 or 1:2 ratio). It should:
  • Mix completely and clearly, without any oily separation or clouding.
  • If it forms layers or looks milky, it might have absorbed contaminants or degraded.

​

3. pH Test (Optional but Useful)​

TEA is a weak base. A 1% to 5% aqueous solution should have a pH around 10–11.
  • If the pH is significantly lower, the compound may have degraded.
  • Use pH strips or a meter if available — this can be quite revealing if you have doubts.

​

4. Functional Developer Test​

If it passes the above checks but you’re still unsure:
  • Mix up a small batch of your intended developer formula.
  • Test it on a scrap piece of film or paper.
  • Observe development time, contrast, and fog.
If development is unusually slow or yields low contrast, your TEA might be compromised — especially if it’s acting as the primary solvent, pH buffer, or part of the developing agent complex (as it often does in concentrated, single-solution developers)

Summary: Still Usable If...​

  • It is clear, not dark yellow or brown
  • Has a normal chemical odor
  • Mixes well with water and doesn’t form separate layers
  • Gives expected pH and developer performance
If it fails any of these tests, it’s safest to replace it, especially when consistency matters in your process.
 

dcy

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I guess my next question would be whether that giant drum is pure TEA or some inhomogeneous mixture.
 
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ntenny

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Unfortunately I don’t know exactly when I bought the previous bottle. It was clearly different, so *something* changed—maybe I spanned the change of supplier, maybe something went wrong in dispensing this particular bottle, maybe there’s been a change inside the drum.

The SDS says it’s 85% TEA, 15% DEA. As @halfaman points out, DEA has a higher freezing point than TEA, but the view of the chemists in the Xtol thread seems to be that impurities will depress the freezing point. I also don’t know how the viscosity of DEA compares to TEA, which would seem more relevant than the freezing point as such.

I don’t have a ready way to test the pH; I guess I’ll try to remedy that next.

-NT
 
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ntenny

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Alan Johnson said:
The Photoformulary site gives an SDS which specifies a freezing/melting temperature of 15.8C 60.4F for the DEA containing version if you care to check.
Click to expand...

Thanks, I missed this.

-NT
 

john_s

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ntenny said:
............., and the next time I mix a batch I’ll try preheating the TEA to drive out any water impurity (as someone suggested in the Xtol thread linked above).

-NT
Click to expand...

Is that a reliable way to reduce the water component? Does it have to reach 100degC, and does that adversely affect the TEA?
 
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