sodium vs. ammonium

[chris_douglas1]

<p>I have been mixing my own chemicals for a couple years now with good results, however, it doesn't appear economical to mix fixer because Kodak fixer costs about half the price of sodium thiosulfate! I have read that c-41 fixer, at 9 bucks for 5 gallons, is the best way to go, even for black and white. I don't mind mixing powders because I have a stirring hot plate, my main interest is long shelf life. In Anchell's, The Film Developing Cookbook, 1998, he states fairly strongly that I shouldn't be using sodium thiosulfate because it can't fix iodide. However, in The Darkroom Cookbook, 2008, he says the only practical difference in sodium and ammonium thiosulfate is time. He seems to have backed away from his earlier opinion. Can anyone confirm that sodium thiosulfate is fine to use, just slower? Also, if I go with c-41 fixer, how good is the shelf life? Thanks for the help.</p>

[edward_zimmermann]

<p>The problem going to the punchline is that with modern films there is a tendency to underfix using sodium thiosulfate hypo. Honestly I see little reason to use it instead of liquid (amonium thiosulate) fixer. I use the stuff as supplied for minilabs as they are cheaper and have more neutral pH than the stuff sold for "B&W". The shelf life of C-41 fixer--- like nearly all mini-lab chemicals--- is very good--- in fact, due to their pH, much longer than those sold for "B&W".</p>

[francisco206]

<p>I have used both, sodium- and ammonium thiosulfate. While there are differences, the one of greatest concern is time, but that applies to both the fixing time as well as the washing time, sodium taking about double the time to fix and to wash. That is true even with a wash aid. Since longer wash times also mean greater water use and water being a resource that should be used conservatively, I opt for the more expensive rapid fix. Shelf life of the sodium thiosulfate (a powder) is longer than the shelf life for ammonium thiosulfate (a liquid), but both are quite long and should present no real issues. In any event, just don't buy more than you would use in a year and you will be just fine. Remember also that while it is possible to mix only part of the powder mix (Sodium Thiosulfate), it may not be wise as the constituent chemicals may not be distributed evenly throughout.<br>

One thing to keep in mind: While we are all in severe economic times and all are looking to save as much as possible, do not become "penny wise, dollar foolish" when it comes to images. You do not want to skimp on what may be a very important image. Do not cut corners unnecessarily on the developing stage -- if you do, there is no way to regain the loss as that is your source image. Better to skip on a cup of coffee every day than to risk what may possibly be your best work.<br>

I hope this helps.</p>

[leicaglow]

<p>Chris, the reason I never endeavored down the c-41 road was because the MSDS I saw, indicated it had a whole bunch of other stuff in it, and I didn't have time to research the impact it would have. Ammonium Bisulfite, Thiocyanic Acid (just to name a couple). Does anyone know what else is in it, and if it has a bad effect on B&W film?</p>

[edward_zimmermann]

<p><em>"...I never endeavored down the c-41 road was because the MSDS I saw, indicated it had a whole bunch of other stuff in it, and I didn't have time to research the impact it would have."</em><br>

No need to worry. C41 mini-lab fixer works perfectly well for B&W. Agfa used to even label a fixer as "Universal" (FX Universal) and sold it for film (C41, E6 and B&W) and paper (RA4 and B&W). Of the various mini-lab fixers it was my favorite although the Champion stuff is not bad either..<br>

I won't purchase any B&W fixer products since they:</p>

<ul>

<li>are more expensive</li>

<li>have significantly shorter shelf-lives</li>

<li>have acid pH which I don't need and don't even want</li>

<li>work at best not better than mini-lab fixer</li>

<li>have, in general, longer fixing times and require longer wash times.</li>

</ul>

<p>The whole differences between C41/E6 fixes and their B&W counterparts is a much more complicated chemistry. Modern colour films have all kinds of inhibitors in them and are much more difficult to fix. One would expect them to be much more expensive than the B&W boutique fixers but due to economies of scale and market differences the sophisticated fixers are the cheap ones selling for less than 1/4 the price....</p>

[chris_douglas1]

<p>Thanks for the response guys. I didn't hear anyone speak up for sodium, message received. I assume Kodak flexicolor comes in a gallon jug and is mixed with 4 gallons of water. Can I store concentrate in smaller bottles and mix up a gallon at a time? Will the concentrate last long this way? I don't use fixer very fast, but at this price I can throw away half of it and still come out ahead. Thanks for any tips.</p>

[chris_waller]

<p>I've just browsed through Walls and Attridge (Basic Photo Science) and Mees and James (Theory of the Photographic Process) and both seem to be saying that it is just a matter of speed, ammonium thiosulphate being the faster. Mees and James note research which indicates that ammonium thiosulphate is more effective when dissolving iodide but both will in fact dissolve it, sodium thiosulphate just being much slower. </p>

[dennis_oconnor5]

<p>This is a 'very' interesting topic. Thanks for starting it.</p>

[frank.schifano]

<blockquote>

<p>Thanks for the response guys. I didn't hear anyone speak up for sodium, message received. I assume Kodak flexicolor comes in a gallon jug and is mixed with 4 gallons of water. Can I store concentrate in smaller bottles and mix up a gallon at a time? Will the concentrate last long this way? I don't use fixer very fast, but at this price I can throw away half of it and still come out ahead. Thanks for any tip.</p>

 

</blockquote>

<p>You can do that, but I've seen no adverse effects from storing the concentrate in a partially full original container either. That's not to say that the shelf life would not be enhanced if you kept it smaller bottles. I'm just saying that I've never had any go bad on me. It works well for B&W materials at 1/2 strength, so don't be aftraid to dilute your working solution 1+9. Naturally, you can expect less capacity this way, but the concentration of fixing byproducts is lower too and I think that's not an insignificant consideration for the longevity of your film and prints. </p>

<p> I haven't seen any of this product sold in 1 gallon bottles for a while now, and I think that size is discontinued. The smallest container I've seen is a 5 gallon bag in a box to make 25 gallons for around $35. That's a lot of fixer, but like I said, it doesn't go bad and is still a good deal if you can source it locally. Otherwise the shipping charges make it less attractive. Costs almost as much to ship it as to buy it. I get mine locally, so shipping isn't a problem.</p>

<p>Do be careful if you go this way. Kodak makes a different formulation for the C-41 RA process, and that one is supposed to be not good for B&W. It works, but some reports indicate deleterious side effects later on. Avoid any fixer that uses RA in the designation.</p>

<blockquote>

 

</blockquote>

[edward_zimmermann]

<p>Actually the C41-RA (RA stands for "Rapid Access") is a faster C41 process. Its fixer is not a bad one. Its, in fact, very close to the <a href="009fBA">"Super Fix" </a>that Ron Mowrey developed. Since fixing times for colour films (both C41 and E6) is cut to 2 min. with B&W......</p>

[chris_douglas1]

<p>I tried to order flexicolor fixer from Adorama tonight and they are "temporarily out" of the handy 5 gallon size. I hope that isn't a disguise for "cancelled", because there is no way I'm going to order 25 gallons! Its too bad too because I was going to order a bunch of stuff while at it to save money on the shipping. Thanks for all the information, everone.</p>

[edward_zimmermann]

<p>Kodak is not the only name in town. Other brands offering a good colour fix are:</p>

<ul>

<li>Champion</li>

<li>Fuji-Hunt</li>

<li>Tetenal</li>

<li>Connect Chemicals Vahingen--- what used to be Agfa Valingen</li>

<li>Calbe </li>

</ul>

<p>There are also a large number of companies that sell to the industrial B&W market---- X-Ray, microfilms, traffic just to name a few----- such as Clayton Chemicals (for those in Los Angeles) that offer less expensive big jugs. These fixers are typically sold direct and are priced accordingly at a fraction of the boutique bottles.</p>

[dennis_oconnor5]

<p>Hello everyone.</p>

<p>I dug-out my old formulae books from the back of a drawer. They are the 'Rayco Formulae' 3rd and 4th editions. I have listed below the formula in case anyone is interested.</p>

<p><strong>C41 Negative Fix.</strong><br /> Ammonium Thiosulphate (crystals) 120g<br /> OR 60% Solution 200 ml<br /> Ammonium Ferric EDTA (50% Solution) 150 ml<br /> Sodium Sulphite (anhyd) 20 g<br /> Potassium Iodide 1 g<br /> Acetic Acid (glacial) 12 ml<br /> Water to 1 litre<br /> The times quoted are: 3' 15" @ 35 C. or 9' @ 25C. It states for ASA 400 and above give 50% longer.<br /> The washing times are 5' for film fix.</p>

<p><strong>Paper Fix</strong> (only slight modification to C41 film fix)<br /> Ammonium Thiosulphate (crystals) 100g<br /> OR 60% Solution 165 ml<br /> Ammonium Ferric EDTA (50% Solution) 140 ml<br /> Sodium Sulphite (anhyd) 20 g<br /> Potassium Iodide 1 g<br /> Acetic Acid (glacial) 12 ml<br /> Water to 1 litre<br /> <em>A note accompanying this formula states it will keep almost indefinitely!</em><br /> The times quoted are: 3' 15" @ 35 C. or 5' @ 24C.<br /> The washing times are 3' for paper fix (but I assume you will be using it to fix film).</p>

<p>In 4th Edition<br /> <strong>Bleach/Fix for paper RA4</strong><br /> Water 700 ml<br /> Ammonium Thiosulphate (60% solution) 150 ml<br /> Sodium Sulphite (anhyd) 23 g<br /> Ammonium Ferric EDTA (50% solution) 75 ml<br /> Acetic Acid (does not state whether it is glacial or % solution) sufficient to bring pH to 6.5<br /> Water to 1 Litre<br /> Time given is (in a jobo CPE2) 1' 50"<br /> Washing time: 35 C = 2'.<br /> I suppose the best way to establish the fixing time would be 2 X clearing time at which ever temperature you process at.</p>

<p>I should give credit to Rayco (no longer trading) for compiling such useful data and to 'The Colour Reversal Club', which I used to be a member of until their demise, for the RA4 formula.</p>

<p>I hope someone finds the above useful</p>

<p>Dennis</p>

[dennis_oconnor5]

<p>I just came across this formula on the link below.<br>

http://www.bonavolta.ch/hobby/en/photo/c41_ra4_chemicals.htm</p>

<table border="1" width="100%">

<tbody>

<tr>

<td colspan="2" width="100%">

<p><em><strong> Dr. Robert Chapman fixer formula</strong></em></p>

</td>

</tr>

<tr>

<td width="75%"><em> Water</em></td>

<td width="25%"><em>750.0ml</em></td>

</tr>

<tr>

<td width="75%"><em> Ammonium Thiosulfate, 60%</em></td>

<td width="25%"><em> 160.0ml</em></td>

</tr>

<tr>

<td width="75%"><em> EDTA</em></td>

<td width="25%"><em> 1.0g</em></td>

</tr>

<tr>

<td width="75%"><em> Sodium Bisulfite</em></td>

<td width="25%"><em> 12.0g</em></td>

</tr>

<tr>

<td width="75%"><em> Sodium Hydroxide</em></td>

<td width="25%"><em> 2.5g</em></td>

</tr>

<tr>

<td width="75%"><em> Water to make</em></td>

<td width="25%"><em> 1.0L</em></td>

</tr>

</tbody>

</table>

[rowland_mowrey]

The C41 fix that Dennis posted above will actually bleach the silver image in B&W film. It is incorrect so please do not use it! Sorry Dennis, but what you posted is an RA BLIX!.......

 

 

 

 

C41 fixers come in two forms. One is normal Flexicolor fix with Ammonium Hypo, and the other is RA fix which contains Thiocyanate and is indeed close to my Super Fix I formula posted here several years ago. I should know, I worked on C41 fixes and blixes in the 60s. ~smiley~

 

 

 

 

The thing to remember is this:

 

 

 

 

Color fixes can be used on all B&W films, but B&W fixes generally cannot be used on Color films due to the pH problem. Color films use a near neutral fix!

 

 

 

 

And yes, Ammonium based fixes will act faster than Sodium based fixes, and also wash out much more quickly.

 

 

 

 

Ron Mowrey

[dennis_oconnor5]

<p>OOOHHH Dear!<br>

Ron.<br>

I am sorry for the unintentional mistake, the name should have given it away 'Bleach/Fix'. I hope the remaining formula's are suitable.</p>

<p>Dennis</p>

[rowland_mowrey]

All of the "Fix" solutions with the words "Ferric EDTA" above are bleaches or bleach fixes depending on the composition.

 

Ron Mowrey

[edward_zimmermann]

<p>I've also scratch all the "fix" solutions since sourcing the Ammonium Thiosulfate will be more difficult and (much) more costly (in the volumes we are discussing) than the purchase of commercial mini-lab fixer. The acid B&W fixers are not just much more expensive but they also have quite short shelf-lives---- contributing also to their cost--- as the Thiosulfate can break down in acid to sulphur.<br>

One side comment: Since the pH of mini-lab fixers is neutral and NOT acid one needs with B/W development using some developers to either include a good wash or a stop-bath. With some older more primitive and easy to scratch films one might want to use hardening fixers--- this is the historical basis for acid fixers in B&W. An alternative, however, to a hardening fixer is a hardening rinse. See: http://www.photo.net/black-and-white-photo-film-processing-forum/00BMgZ</p>

[dennis_oconnor5]

<p>Have you ever tried to be helpful and ended up doing more harm than good?</p>

<p>I have put a couple of monochrome films (Fomapan 100 and Legacy 400) through the 'Fix' formula's I posted earlier. It transpired just as Rowland predicted. There is indeed bleaching of the images, even with fixing times of 90".</p>

<p>So. As Rowland stated 'Do Not Use The Formula's I Posted' for monochrome films.</p>

<p>I am sorry for any inconvenience I may have caused with the posting.</p>

[rowland_mowrey]

Edward, one thing that I note from that old reference you give is the fact that I forgot to mention that aldehydes are not generally compatible with alkaline ammonium fixers. The ammonium ion can react with the aldehyde and destroy both the fixing properties and the hardening properties. An aldehyde based hardening fix should be based on Sodium Thiosulfate! I did not make that clear in my earlier post although I did describe the Kodak AFHF, or Alkaline Formalin Hardening Fix which contained only Sodium ions.