aldevo said:I recently purchased 100g of pyrocatechin with which to mix Gainer's Cat-P-TEA recipe.
Opening the container I noted that the pyrocatechin seemed composed of many small off-white colored granules along with many much larger 3- or 4-sided flat leaflets. The container gave off an acrid odor. Not familiar with the physical properties of pyrocatechin I just went ahead and mixed the developer.
It hasn't worked well. Even developing 400TX negs in 135 to 13.5 minutes at 70 degrees is resulting in very flat negatives with no evidence of stain. I'm using Formulary TF-4 for fixing and no hypo clear or sulfite after bath. I rinse for 25 minutes after in water with a tested PH of about 6.5 or slightly higher.
Is the pyrcatechol indeed bad or is it something in my process?
Thanks.
aldevo said:Increasing development time from 10.5 to 12 to 13.5 minutes had little effect on overall negative contrast. The EI was 250 and the negatives appear to have satisfactory shadow detail.
Again, they are just very, very flat.
WarEaglemtn said:"If it is bad, the Formulary will replace it.
You are better off dealing with Artcraft chemical. My experiences with Formulary are less than positive... and no, they don't like replacing chemistry that is bad. They have more excuses than a HongKong whore.
WarEaglemtn said:"If it is bad, the Formulary will replace it.
You are better off dealing with Artcraft chemical. My experiences with Formulary are less than positive... and no, they don't like replacing chemistry that is bad. They have more excuses than a HongKong whore.
Formulary/Bud Wilson said:I prefer that customers who have much experience dealing with "HongKong whores" as you apparantly do, find a more suitable place to do business than with the Formulary.
As far as the Catechol mentioned in this thread, yes it looks and smells just as described, and this is the way Catechol has looked and smelled for the 28 years the Formulary has been selling it. If anyone can find a more suitable product to mix up the formulas listed on APUG and other sites please advise me and I will try to obtain it.
Best Regards
Photographers Formulary
An APUG sponsor
Bud Wilson
I hope there is no misunderstanding. I don't disagree with Sandy's comments. It is possible that the TEA I used in my original experiment had more DEA in it than the 99 % stuff. I know that the synergism between phenidone and ascorbic acid takes place at lower pH, and that a combination of phenidone, ascorbic acid and catechol can work at lower pH than 10 without sulfite. I don't know why, but I have an idea that the autocatalytic nature of the development of silver halide and the fact that the synergism between ascorbic acid and phenidone needs no sulfite has something to do with it. A dilution of 1+25 should bring the pH up to the required level.sanking said:As a general rule I try to limit my contact with folks who have a lot of experience with "Hong Kong whores."
The absurdity of this thread is that in all probability there is absolutely nothing wrong with the catechol. As I have explained, TEA does not provide sufficient pH to drive catechol developers, and I know this from experience, having mixed up and tested the cat-p-tea formula, as well as a number of variations using catechol in TEA. For a fairly good working catechol developer you need to get the pH up to around 10.5 or more, and cat-p-tea formula, diluted 1:50, barely gets the pH to 9.5.
Sandy
gainer said:I hope there is no misunderstanding. I don't disagree with Sandy's comments. It is possible that the TEA I used in my original experiment had more DEA in it than the 99 % stuff. I know that the synergism between phenidone and ascorbic acid takes place at lower pH, and that a combination of phenidone, ascorbic acid and catechol can work at lower pH than 10 without sulfite. I don't know why, but I have an idea that the autocatalytic nature of the development of silver halide and the fact that the synergism between ascorbic acid and phenidone needs no sulfite has something to do with it. A dilution of 1+25 should bring the pH up to the required level.
Now pyrogallol and TEA is a different story, but not an issue here. The original issue was the purity of a batch of catechol that had a phenolic odor and a non-uniform particle shape. I thought it was allways that way.
I probably would not use the formula I originally proposed except perhaps to try it for stand or minimal agitation. I have come to the conclusion that single solution developers, by and large, have an optimum dilution and not very much latitude for increase in the ratio. I mean that if 1+25 works well, 1+50 may hardly work.sanking said:I hope you don't read my comments about pyrocatechol and TEA as critical of your work. There is no question but that the cat-p-tea works, it is just very slow working. That may not be undesirable for silver printers, but it is no good for my work. It may be that adding ascorbic to the mix would allow a lower pH, but I have not pesonally tried that. However, I still believe that to get good activation from pyrogallol you need to get the pH up to at least 10.5.
My point is that the low contrast described in the original thread should not be seen as unexpected or the result of bad pyrocatechin. To the contrary, the results are entirely consistent with my own experiments with good pyrocatechin and TEA. If you revisist this and get different results let me know as I would be interested in a fast working pyrocatechin based developer mixed in TEA.
Sandy
gainer said:I think I will still prefer the versatility of the 2 solution stock with glycol as solvent for the developing agents.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?