I have the TF-4 as the complement to 510-Pyro.
The Acetic acid has lived in a kitchen cabinet for a long time, never opened !! lol
If, for whatever reason, you want to stay alkaline throughout the process, then a stop bath made from 100 g/l KBr + 20 g/l NaHCO3 has near infinite shelf life and can be set at any pH you want, e.g. near neutral slightly alkaline with Sodium Bicarbonate alone, slightly more alkaline by adding Sodium Carbonate.
Ah, this is great, basically a bath saturated with bromide so the developer can’t put any more of it into solution. I like it.
??? Please explain why not when every film/chemical manufacturer states to use a stop bath between developer and fix?
Use of an acid stop bath will strip the pyro stain.
Doesn't TF4 come as a concentrate with some undissolved solids in the bottle? With the instructions to mix all of it and make a working solution? Perhaps the sediment is a poorly soluble alkali and it shifts pH above 7, making it alkaline. Isn't TF4 also supposed to be well buffered and capable to cope with stop baths?
I’ve never seen this stuff, but I don’t like the idea of undissolved particles around my films. I always filter solutions before use, to help limit the amount of retouching to be done on prints.
That myth just doesn't want to die, does it.
Recent, independent experiments. Same outcome. Pyro stain doesn't die just like that. Feel free to use an acid stop with your pyro developer - it won't affect the stain.
PS: I hold no financial interest in the acetic acid industry.
TF4 has a component that is semi-opaque and tends to settle to the bottom of the jug (the concentrate, NOT the diluted working solution!). It is clearly stated on the bottle to SHAKE WELL before using. Once mixed with water, the solution clears and there is no separation of components. There are no “undissolved particles”.
TF4 is a superior fixer in many ways, including the fact that film washing is significantly faster: 5 minutes and you’re done. It’s all I use now.
TF4 has a component that is semi-opaque and tends to settle to the bottom of the jug (the concentrate, NOT the diluted working solution!). It is clearly stated on the bottle to SHAKE WELL before using. Once mixed with water, the solution clears and there is no separation of components. There are no “undissolved particles”.
TF4 is a superior fixer in many ways, including the fact that film washing is significantly faster: 5 minutes and you’re done. It’s all I use now.
Saturated is probably not the ideal composition. You could dissolve a lot more KBr, but you would inadvertently create a fixer instead of a stop bath. Halides are known to form soluble silver complex, if they are present in sufficient quantity, there are even fixer patents for concentrated iodide solutions.
The number 100g was suggested to me by Ron Mowrey, who, unlike me, tested it, and I would be careful before going far above this amount.
Interesting, well the next step in a negative process would be fixing anyway so precision may not be as important.
Hi, with D23 developer;
What is the opinion on using TF-4 Alkaline Fixer?
I also have a bottle of Acetic acid, that I could mix for a stop bath.
if the these two combinations would work,
may I ask please, what ratio of Acetic acid to distilled water is recommended?
thanks very much!
Traditional 2% seems to have had a considerable amount of excess usage in mind. Since I use the stop one-shot, even 1/2% is plenty strong.
Ron Mowrey/PE who was one of the formulators of TF-4 recommended using an acid stop bath with alkaline fixers, he had seen dichroic fogging a few times with just a water stop bath.
Is TF-4 an Alkaline fixer, the concentrate has a pH of 5 according to the MSDS, the working solution closer to pH6, that's the wrong side of pH 7 - Neutral to be Alkaline. My understanding from what Ron wrote was TF-4 was buffered to be close to neutral when mixed with water and remain odourless, and that without an acid stop bath it could become alkaline and cause Dichroic fog and also Ammonia fumes
Ian
Bill Troop has said it is unlikely to get dichrotic fog with modern films.
The home mixed TF-2 is similar to TF-4. It is a rapid alkaline fixer. I have used it with film.
The ammonia smell is a bit more than TF-4 & TF-5 so is good for tanks but not for paper or open trays. It is inexpensive. I now use TF-5 which I think is the premier fixer. I am in the no stop bath for film camp because the arguments for using stop have not seemed persuasive to me.
TF-2 is not a rapid fixer and therefore quite inferior to TF-3/4/5. TF-3 was the last one of Bill's fixers with a public formula.
I would expect TF-3 and TF-4 to reek to high heaven in an open tray, but TF-5 should be completely odorless at pH 6.5.
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