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Hello, a few questions about TF4 alkaline fixer and stop bath

bryans_tx

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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!
 
mshchem said:
Shouldn't need stop
Click to expand...
??? Please explain why not when every film/chemical manufacturer states to use a stop bath between developer and fix?

Good grief, hasn't the discussion between vinegar and stop been beaten to death?

How long does the fixer last if constantly exposed to developer last?

I know that you're a chemist, but??? I'm at a loss.

Sirius Glass should chime in here.
 
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We have tomes on whether or not stop bath is necessary!
I'm in the "use it" camp.
To the OP - what is the concentration of the acetic acid you have? And if you have glacial acetic acid - nasty stuff! - are you experienced in handling it?
Your target concentration should be about 1.5% to 2.0% for working stop bath.
 
The general idea with an alkaline fixer is to keep the whole process alkaline. There is no real reason to use an alkaline fixer with an acid stop bath. If you want to use a n acid stop bath rather than a water bath (a point not worth debating again) then just use regular acidic or neutral fixer. They are easier and cheaper to get.

The data sheet for TF-4 says:
• No stop bath necessary. Just use water rinse after developing.
Click to expand...
 

Yeah, it would be probably best to just search the site for the discussions on this, would make a good tome. It's between, tell to stop in order to sell more product (with some scientific prove) vs. tell not to use ...'cause countless users have never done so.

Stop bath can be important with short development times, once long time techniques are used, it becomes more and more moot the longer you take to complete development.
 
Tim Stapp said:
Good grief, hasn't the discussion between vinegar and stop been beaten to death?
Click to expand...

Yes. I expect we're going to beat it some more, though. It's useless, but hey, if it can be done, we should, right? Let me give a TL;DR before we start off (again...): it doesn't matter much whether a stop bath is used for B&W. Furthermore, with an alkaline fixer, the buffering of the fixer is strong enough to make the use of an acidic stop bath totally unproblematic. Flip a coin and proceed.

I've added 'TF4 alkaline' to the thread title to make it a little more descriptive of the content.
 
If you go back a hundred years or so, the stop bath served a couple purposes. One thing was to neutralize the alkaline developer to protect the acidic fixer.
Some stop bathes included chrome alum to harden the emulsion, especially important in so called "tropical development'.

Stop bath is a ritual. I always use stop bath.
 

It is very nasty and dangerous stuff. Ilford makes a odorless citric acid stop bath, this is what I use. I have a bottle of glacial acetic and in case we get a earthquake, I keep it in a covered 5 gallon plastic bucket under a big stainless sink in the basement.

If you want to lower your property value spill glacial acetic acid
 
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.

koraks said:
I've added 'TF4 alkaline' to the thread title to make it a little more descriptive of the content.
Click to expand...

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
 

Correct. If you use TF-4 (an excellent choice) there is NO NEED for a stop bath.
 
Ian Grant said:
The MSDS says the pH is 5 which is acidic, and Ron Mowrey stated it was Neutral, he also called it an Alkali fixer.

Ian
Click to expand...

Yeah, I really don’t know. I always saw the Formulary call it alkaline. I don’t have any TF-4 to measure, but “neutral” is often anything from 6 to 8. But “alkaline” would normally mean near 8 or more. Maybe somebody has some TF-4 working solution and a pH meter or some paper test strips handy.
 
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?
 

Yes and we all know that stop bath, stop bath with indicator and Acetic acid are just so damned expensive! But for black & white film, TF4 and TF5 do not need stop bath et al. Color film is another discussion.
 
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Sirius Glass said:
Yes and we all know that stop bath, stop bath with indicator and Acetic acid are just so damned expensive! But for black & white film, TF4 and TF5 do not need stop bath et al. Color film is another discussion.
Click to expand...

No memes. I need memes to understand. Bold large letters just don't cut it.
 
Thanks for the education!
The Acetic is Formulary brand 99%.

As my budget is getting quite limited, I did not want to have to spend the money on a Stop bath and shipping!
I already have the TF-4 Fixer.
 
Good point, if there are solids in the bottle then this could substantially change the pH when in working solution.
 
I have no opinion on stop bath yes/no, but that pH 5 number is odd. It is even more odd, that TF-5 lists the exact same number, and it is yet more odd, that a density of 1.07 @ 20°C is given in the same section. Compare this to typical densities of liquid rapid fixer concentrates, which circle around 1.34 @20°C. The specific gravity number would at least be in line with typical rapid fixer working solutions, but the pH numbers are most likely incorrect.
 

Looks like a working solution specific gravity if you dilute it to 5 times the original volume with water. The pH value then is likely a typo. Oh well, 5 is just below 8 at a keypad.
 

TF-4 is a highly effective fixer with good capacity. I would recommend it.

Rather than using acetic acid as stop, use citric acid. A kilo of food grade citric acid is dirt cheap, safe and easy to handle, and most of all is odourless. I mix up a ~ 1% solution of it fresh each time before use (if you store stock solutions of it long term, mould will grow in them).
 
Thank you
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

Also, I should apologize for not searching, since I now see there is a hot topic thread on stop baths. I did not mean to over agitate the collective film

For a laugh of sorts, I finally opened a box that arrived in 2016... inside was a rotary motor and cibachrome cylinder. Most likely bought it from the classifieds here. haha.
Not sure what I am going to do with it now!
 
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