Alkali vs Acid Fixers

[Paul Kinzer]

I feel a bit odd posting this: I am an absolute newbie to film development, so have little confidence in the theoretical knowledge I've attained through research and reading. But much of that reading is based on books that are often out of date, so I wonder if some of the information in them might be, too.

Anyway, while exploring for the right chemicals for my foray into B&W film development, I came across the Photographer's Formulary page (http://stores.photoformulary.com/art-fix/) describing their Art Fix alkali fixer. From what it describes, acid fixer seems like something that should just no longer be used. I won't go into all the details they do, but the page seems worth a read. They sure make it seem like alkali fixer is just a simpler, better answer.

I'd really be interested in what folks with experience have to say about this.

[Michael R]

Be careful what you read. What's written in the linked page ranges from true, to partially true, to it depends, to not true.

Neutral/alkaline fixers can have a few benefits vs equivalent acidic fixers depending on formulation, how acidic the acid fixer is, hardening vs non-hardening, regular vs rapid, etc. Without getting into too many details, the main benefit of non-acidic fixers - generally speaking - is that they will tend to wash out of photographic materials (particularly fiber-based papers) faster than acidic fixers. However it really depends on which acidic fixer and alkaline fixer you are comparing. Non-acidic fixers can also be more stable and have higher capacities, but again it depends on the formulation.

Note Art Fix is not a rapid fixer. If you want to use one of Formulary's fixers, I'd first suggest TF-5, which is a neutral rapid fixer and pretty much the state of the art as far as commercially available products go. Try TF-4 if you want an alkaline rapid fixer.

[LabRat]

Michael is right, "beware of information"...

First, hypo based fixers do vary quite a bit, so look up each formula to see the differences... Acid fixers were to neutralize alkaline carryover from the developer (to stop combined fixing/development that could happen at the same time if a proper stop bath was not used), provide the optimum pH for the clearing action, provide a proper environment for the addition of hardening agents, and a consistent fixing action (as the fix became more alkaline)...

But I may confusing this with ammonium thiosulfate based (rapid) fixers that I make/use... (I prefer them as they fix faster and well, last long, soak into the paper bases less, work cleaner (don't stain/oxidize), and are much easier to wash out of materials in shorter wash times at different washing temps...)

All of this has been extensively tested many years ago by the research departments of the mfgs, so what you find in the old photo reference books is still valid...

Steve K

[Paul Kinzer]

Okay, thanks! I obviously still have a lot to learn.

I'm trying to come up with simple, relatively clean, and fairly inexpensive developing chemicals. At this point, speed is not really an issue for me. I'd like something as foolproof as possible, so something that takes time seems like an okay idea. According to the link in my OP, modern films do not require hardener, which was news to me (and not mentioned in my reading, unless I missed it). The link also said that plain water is all that's needed for a stop bath with the Art Fix, which also seemed like a simplification.

I am thinking about using divided D76, and the Art Fix seemed like a good match for it (but what do I know?). I'm never going to be more than an occasional LF photographer, and I'll be developing film even less often; maybe 25-50 sheets this year. I don't, at this point, plan to do any printing with chemicals; I'll be sticking to scans for now. I'm also thinking of using an 8x10 Unidrum for developing two sheets of 5x7 Ilford FP4 at a time.

Is there any reason that I should not do what I just described? By that I mean, two different things. First: will it not work for some technical reason? And/or, Second is there a better way, based on my priorities (simplicity, cost, and cleanliness)?

I feel a bit like I'm cheating by asking up front, 'Tell me just what to do!' On the other hand, there are so many choices (which is a good and cool thing that I may eventually try my hand at experimenting with) that I'd like to just get started right the first time. I know that 'right' is purely subjective, but I'd like to get started without messing up, and if the way /I start can be a way that works long term, so much the better.

[Doremus Scudder]

Paul,

First the fixer question: Alkaline fixers, as mentioned, wash out more quickly. This is of primary importance with fiber-base papers. That said, there are a lot of slightly-acid and neutral fixers out there that work just fine. The real thing you should be aware of is the difference between sodium thiosulfate (hypo) fixers and ammonium thiosulfate (rapid) fixers. The former take much longer to fix and may not fix some modern films (e.g., TMax) completely. Rapid fixers are significantly faster and are recommended by the manufacturers for both TMax and Delta films. I think most of us now use a rapid fixer in some incarnation or other. My fixer(s) of choice is Ilford Rapid Fixer (or Hypam). It (they) are very slightly acid at working dilutions and come in convenient liquid concentrates. TF-5 would be another recommendation. It is neutral pH.

As for your suggested work flow related to your question, "is there a better way, based on my priorities (simplicity, cost, and cleanliness)?" I would question a couple of things.

First, if you plan on processing only occasionally, I'd try to keep things simple and use everything you can from liquid concentrates that have a long shelf life. Why divided D-76? You have to mix it from powder, which means you have a stock solution with a shorter lifespan. Plus you have two developing steps, which is really unnecessary for 99% of cases. A developer like HC-110 or Ilford IlfotecHC comes in a concentrate that will last for years. If you mix just what you need for a single session directly from the concentrate, the concentrate will last years. There are other developers like this too, e.g. Rodinal or, my standard, PMK, but the two mentioned above will give results very, very like D-76.

The same with stop and fix. I use an Ilford citric-acid stop bath and mix up just what I need for a single session from the concentrate. It lasts for years. Ilford Rapid Fixer (or any rapid fixer that comes in a liquid concentrate, for that matter) can also be diluted right before use to make the volume you need for a single session. Fixer concentrate in a partially-filled container has a shelf-life of 6 months to a year. So, why mix working solutions and have them sitting around in bottles taking up space and getting too old to use?

And, although I won't tell you what to do, I will give you some recommendations based on my 30+ years of darkroom experience and reading and research :)

Do use a stop bath. It stops development quickly and reliably, prepares the neg for the fix and is simply more reliable and simpler than a water bath.

Go for a rapid fixer (i.e., ammonium thiosulfate based). The Art Fix fixer you mention is a sodium thiosulfate (conventional/slow) fixer, and seems to be rather finicky and fragile (a stop bath will ruin it...) Note that alkaline TF-4 and neutral TF-5, both formulated by Kodak engineer Ron Mowrey - PE here on the forum, are designed to work with a conventional acid stop bath and are rapid fixers. I'd recommend either of those along with the Ilford products I mentioned before Art Fix.

And ditch the fancy-schmancy divided developer if you're just starting out. Use a liquid concentrate that lasts a long time if you only develop occasionally.

Best,

Doremus

[Paul Kinzer]

Thanks, Doremus!

I freely admit that I don't know what I am doing. The ideas I had were based on conclusions I reached after the (fairly detailed but limited) research I've done. But since I don't really have a base of experience to draw from, I'm happy to be corrected. I had not really thought about the advantage of liquid concentrate. I'm especially appreciative of specific recommendations. They give me a direction for more research.

I must say that, even though I have yet to put any film into chemicals, I am having a fascinating time reading and thinking about all the possibilities. I cannot think of many other pursuits that have such a strong mix of absolute and precise empirical actions that are used in pursuit of a wide range of subjective artistry.

Again, many thanks!

Paul

[Paul Kinzer]

So, now that Ive been appropriately shot down, what would be a good starting place for me? I hope to do some 5x7 photos with Ilford FP4. Developing in a constantly turning 8x10 Unidrum seems like something that will work in my space and with my skill set. Concentrated liquid that keeps a long time seems like an excellent idea. Would Ilfotec, an acid stop bath (which one?) and TF-5 be a good combination. How about Rodinal? How would it be different from the Ilfotec if used with what I've described? Are there downsides to any of these (staining, smell, toxicity, finickiness)?

Maybe I should do some more reading. I have a couple of more books on the way. But specific suggestions will make my reading more focused, so I'd be grateful for more!

[jvo]

paul,

with all due respect, i'd suggest you do some processing rather than reading.. you have enough info from your reading, and the replies here... have some fun!

jvo

[axs810]

Paul,

First the fixer question: Alkaline fixers, as mentioned, wash out more quickly. This is of primary importance with fiber-base papers. That said, there are a lot of slightly-acid and neutral fixers out there that work just fine. The real thing you should be aware of is the difference between sodium thiosulfate (hypo) fixers and ammonium thiosulfate (rapid) fixers. The former take much longer to fix and may not fix some modern films (e.g., TMax) completely. Rapid fixers are significantly faster and are recommended by the manufacturers for both TMax and Delta films. I think most of us now use a rapid fixer in some incarnation or other. My fixer(s) of choice is Ilford Rapid Fixer (or Hypam). It (they) are very slightly acid at working dilutions and come in convenient liquid concentrates. TF-5 would be another recommendation. It is neutral pH.

As for your suggested work flow related to your question, "is there a better way, based on my priorities (simplicity, cost, and cleanliness)?" I would question a couple of things.

First, if you plan on processing only occasionally, I'd try to keep things simple and use everything you can from liquid concentrates that have a long shelf life. Why divided D-76? You have to mix it from powder, which means you have a stock solution with a shorter lifespan. Plus you have two developing steps, which is really unnecessary for 99% of cases. A developer like HC-110 or Ilford IlfotecHC comes in a concentrate that will last for years. If you mix just what you need for a single session directly from the concentrate, the concentrate will last years. There are other developers like this too, e.g. Rodinal or, my standard, PMK, but the two mentioned above will give results very, very like D-76.

The same with stop and fix. I use an Ilford citric-acid stop bath and mix up just what I need for a single session from the concentrate. It lasts for years. Ilford Rapid Fixer (or any rapid fixer that comes in a liquid concentrate, for that matter) can also be diluted right before use to make the volume you need for a single session. Fixer concentrate in a partially-filled container has a shelf-life of 6 months to a year. So, why mix working solutions and have them sitting around in bottles taking up space and getting too old to use?

And, although I won't tell you what to do, I will give you some recommendations based on my 30+ years of darkroom experience and reading and research :)

Do use a stop bath. It stops development quickly and reliably, prepares the neg for the fix and is simply more reliable and simpler than a water bath.

Go for a rapid fixer (i.e., ammonium thiosulfate based). The Art Fix fixer you mention is a sodium thiosulfate (conventional/slow) fixer, and seems to be rather finicky and fragile (a stop bath will ruin it...) Note that alkaline TF-4 and neutral TF-5, both formulated by Kodak engineer Ron Mowrey - PE here on the forum, are designed to work with a conventional acid stop bath and are rapid fixers. I'd recommend either of those along with the Ilford products I mentioned before Art Fix.

And ditch the fancy-schmancy divided developer if you're just starting out. Use a liquid concentrate that lasts a long time if you only develop occasionally.

Best,

Doremus


Wait you can use an acid stop bath with tf-4? I was under the impression a water stop bath is better for tf-4. Mind educating me on this?

Edit/ say if you do use an acid stop bath with tf-4 does that do anything to the wash cycle times or life of the fixer?

[LarsAC]

Keep things simple at the beginning until you achieved consistent handling of all steps and can roughly control / judge relevant parameters such as developer time, dilution, etc. Well established developers have the advantage that you will get quite good feedback in case of difficulties.

Trying to save some cost is a reasonable goal, but your learning curve will be better with good quality material as it may be difficult to distinguish processing issues frim material fault.

Lars

[Doremus Scudder]

Wait you can use an acid stop bath with tf-4? I was under the impression a water stop bath is better for tf-4. Mind educating me on this?
Edit/ say if you do use an acid stop bath with tf-4 does that do anything to the wash cycle times or life of the fixer?

Take a look at the following thread about using an acid stop with an alkaline fix on APUG: http://www.apug.org/forum/index.php?threads/alkaline-fixer-acid-stop-bath.69029/

I'll take the liberty of quoting PE (Ron Mowrey) from his post #4 in the above thread:
"I have run TF-4 with a stop and a water rinse testing varying levels of running water and still water in the rinse. I have gotten various levels of fog in standing rinses even with a fresh charge of water in the tray, or with a low rate of running water. I have never gotten fog when I use a stop bath and I have never hurt the TF-4 or print by using a stop. This all refers to prints on FB or RC. The fast rate of development is the issue here combined with alkali and a silver halide solvent. That can fog paper emulsions. So, my workflow for prints using TF-4 always includes a stop."

The same should apply to film (even though fog is less of an issue with film than prints, it is still a degradation and affects shadow separation). Certainly, the fixer itself works just fine with a stop bath. FWIW, even with an acid stop, I have had film fog in an alkaline fixing bath from a combination of carried-over developer, which gets reactivated in the alkaline environment of the fix, and turning the white light on too early. I like TF-5 from printing, but use Ilford Rapid Fixer for film for just this reason.

I hope that PE's quote and the rest of the discussion in the linked-to thread clears things up (pun intended).

Best,

Doremus

[Andrew O'Neill]

I won't go into all the details they do, but the page seems worth a read. They sure make it seem like alkali fixer is just a simpler, better answer.

Of course they say this because they want to sell TF5. I've used both alkali and acid fixers. They both work. I prefer Ilford Rapid as it's cheap and readily available.

[Jac@stafford.net]

Of course they say this because they want to sell TF5. I've used both alkali and acid fixers. They both work. I prefer Ilford Rapid as it's cheap and readily available.

So true, Andrew!

I repeat to the OP the group's advice to use economical chemistry. It has a huge customer base BECAUSE IT WORKS so very well. D-76 and Rodinal have been my friends for fifty years.

Very best of luck.

[brad martin]

Paul,

Fixers are either Sodium or Ammonium based. With Sodium based you'll need a hypo clear. Or at least that's my understanding. You can get something like TF-4 from Photographers Formularly or Ilford Rapid Fixer from a lot of places. No hypo clear required. I've used TF-4 for a long time. Before that Ilfords rapid fixer. Now I've starting mixing my own TF-3. Do you need a stop bath? No. But get some anyway. If I use a stop bath it's at half strength. I've never noticed fog.

If you're just starting out keep it simple.

The most important aspect of darkroom work is a methodical workflow, good cleanliness practices, and adequate washing of film and paper.

[AuditorOne]

D-76 is a great developer, whether you use the Kodak stuff or the divided D-76 found at Photo Formulary. Rodinal is another terrific option and, if you don't shoot and develop a lot, will save practically forever. Another great developer is HC-110. It too is liquid and lasts for a very, very long time.

I now use TF-5 or I mix my own fixer using Sodium Thiosulfate (which has worked very well for at least a hundred years and seems to work just fine for me.) Contrary to popular belief it fixes TMX100 just fine, it just takes a couple of minutes longer.

Start with a basic setup like Rodinal, vinegar stop and Ilford Rapid Fixer and you will do great. Once you are ready to move on, though you wouldn't have to, you can start experimenting and trying things for yourself. A lot of what you will read, even here, amounts to preference by individuals, or advertisement by companies, rather than actual rules that cannot be broken.

Right now I use D-23, Beutler (both of which I mix myself) and Rodinal. to develop my film. I use a vinegar stop bath and TF-5 or hypo to fix. I also use Mirasol as a final rinse/surfactant to prevent water spots on my drying film. It all works.

If you would rather keep things a little more economical then go to Freestyle and pick up some of their Arista branded products. This is what I used when I first started and may end up going back to again.

I used water to "stop" development before dumping in the fixer but if you want to use your fixer more than once or twice you probably should consider white vinegar or a citric based stop bath.

[Pere Casals]

stop bath

Read this book as soon as possible: http://www.ssnpstudents.com/wp/wp-content/uploads/2015/01/Focal-Press-The-Darkroom-Cookbook.pdf


Page 103 explains all you need:


Stop bath stops all development in some 15s, plain water in some 30s. So at the end you have give some 15s less development time with plain water stop. That's all.

As you are not to use an acidic fixer you do not need to protect fixer with the stop bath, even I guess it is not a good idea to throw remains of an acid stop bath to an alkali fixer.

Acid stop bath made sense in the acidic fixers age, today rapid fixers are a common choice.


From the mentioned book:


"Even so, the disadvantages to using acid stop bath are:

When sodium carbonate, one of the most commonly used alkali in fi lm developers, comes into
contact with acid, carbon dioxide gas is released which can cause blistering in the emulsion of
both fi lm and paper. The problem is more critical in fi lm where it is appears as a pinhole, usually
in dense areas of silver deposits such as the sky.

If an acid bath is to be used there are two methods to prevent pinholes from occurring.
1. Use developers compounded with mild alkali, either sodium metaborate or borax, which do
not create carbon dioxide gas.
2. Use a 3% to 5% solution of sodium metabisulfi te, a 3% solution of chrome alum, or a mildly
acid stop bath, such as Kodak SB-1 Nonhardening Stop Bath. Or use a very gentle-acting stop
bath, suggested by Jay Dusard, comprised of a solution of 10.0 grams of sodium bisulfi te in 1.0
liter of water.


The fumes which emanate from acetic acid stop baths are perhaps the single greatest health hazard
in the darkroom. Over time, these fumes can cause damage to the delicate membrane of the
sinuses, resulting in respiratory problems. For this there are also two solutions.
1. Use an odorless citric acid stop bath such as Kodak SB-8.
2. Stop using stop baths altogether. Instead, substitute a one minute running water bath between
the developer and fi xer, for both fi lm and paper. If running water is not available fi ll the tray
or tank with fresh water, agitate for 20 to 30 seconds, dump, and repeat three times."


Anyway a lot of people uses acid stop bath with good results. I had been using it a lot. Now I don't use it since I got some pinholes, and by consulting the Anchel's book because the pins I found I was not necessary at all, you need 15 seconds more of stop bath but 15 second less of development.


As it looks you want to learn, just read the Anchel's Book, a great reference !!!

[Paul Kinzer]

I do own and have read The Darkroom Cookbook. Someone in a thread here said it had some errors that he knew of, so he worried it had others he did not. Still, it has been the basis of my rudimentary understanding of film processing.

In post #8 of this thread, jvo wrote, 'with all due respect, i'd suggest you do some processing rather than reading.. you have enough info from your reading, and the replies here... have some fun!' I see the point, and understand that it may get tiring answering the same questions again and again, but this thread shows my difficulty. Differing opinions and lots of suggestions are confusing (and this is just one thread). Still, it's obvious that I'll have to just make my own decisions in the end, since there are so many perfectly fine choices.

So, concentrated liquid seems like a no-brainer now, and that will take some possibilities off the table. And TF-4 or TF-5 for fixers works for me. Rodinal sounds fine as a developer, but someone elsewhere said it did not do well with lots of agitation. Is that only in some concentrations? I think I'm going to use a drum and constant agitation for processing. Would this be a problem with either Rodinal or the TF fixers?

And a citric acid stop bath sounds pleasant. But then someone mentioned pinholes.

I guess that I feel ready to make actual choices now, if my suggestions here don't raise any issues. Does anyone see any? I plan to use Ilford FP4, and the chemicals I just mentioned, in a constantly agitating drum. I guess the two potential issues I see, based on my reading, are pinholes and Rodinal not liking the drum developing.

I know I keep asking questions, but I do want to know before spending my funds, and before potentially ruining images. And I figure others might have the same questions, and will find the answers by reading this thread.

[Pere Casals]

I do own and have read The Darkroom Cookbook. Someone in a thread here said it had some errors that he knew of, so he worried it had others he did not.

Any book can have some errors. Also in processing there are some controversies, Anchel addressed that by mentioning those controversies.

For example, some say a pre-rinse (pre-soak) is very benefical, but Ilford datasheets say don't do it with tanks, if you dig, this is because it removes surfactants from emulsion that are good for development.

These are minor things, but if someone knows a clear conceptual mistake... What the hell that mistake is ?

IMHO you can trust completely that book, as one advances a lot in skills then one can have some discrepances, of course. The book combines trustful technical knowledge with some author's opinions when it is worth, anyway when something is an opinion it is well said in the book.

My recommendation is you use that book as your trustful reference, at least until you are very confortable with processing, then you can look for variants and other books.


A film photographer can make impressive prints without being much concerned with technical issues, as common recipes work very well, anyway spending some 50 hours by reading selected technical books gives a technical background that IMHO is completely worth.

Then it is also interesting reading books about the art share of photography, and about history...

My final word, IMHO you can trust Anchel's books, if someone speaks about errors then ask.... what errors ???

Next step can be "Beyond The Zone System" book, an advanced reference for calibrations, or a lot that are there.

Regrads

[LabRat]

There are typo errors in published formulas in different books (and online), so it is always a good thing to look up the same formula from at least two sources before using... You might find different mixing & use notes in different places, too...

Minor errors usually will usually not make too much of a difference, but things like gross dilution errors certainly will... But always cross-check formulas, and test on non-important film first, until you get the hang of them...

Steve K

[Pere Casals]

some errors


There are typo errors in published formulas in different books (and online), so it is always a good thing to look up the same formula from at least two sources before using... You might find different mixing & use notes in different places, too...

Minor errors usually will usually not make too much of a difference, but things like gross dilution errors certainly will... But always cross-check formulas, and test on non-important film first, until you get the hang of them...

Steve K

Hello Steve,

I agree, cross-checking is good, still erros can be copied from one source to another.



Second and third editions should be mostly error-free.

First edition of The Darkroom Cookbook has 2 major mistakes: FX-39 developer formula contain too much benzotrialzole, that would act as a toe cutter at 10x concentration, I guess. And FX-1 formula, completely wrong in one of the versions (the stock one in page 126, the other in page 59 is right).

But there are a lot for formulas there... and the really important thing for a learner is the conceptual matter.


Here you have the errata notice, with all the corrections:

http://anchellworkshops.com/books/errata/fdc_errata.pdf



When I re-learned film/paper processing (after a lot of years) I found no error in the Darkroom Cookbook that would cause any trouble in my learning process.

Just the counter, I'm very grateful to Mr Anchel because the plain and honest way the book was written. This is not only a commercial work, I feel he put best of him to help other in the path of learning darkroom skills, promoting a critical view from the learner.

This honestity is something we can see in other texts, of course, but this book excels in that, IMHO.

Regards

[LabRat]

Hello Steve,

Here you have the errata notice, with the corrections:

http://anchellworkshops.com/books/errata/fdc_errata.pdf


When I design an electronic board I read the errata before the datasheet or the reference manual of components, as most electronic designers. This is very well invested time.

But... when I re-learned film/paper processing (after a lot of years) I found no error in the Darkroom Cookbook that would cause any trouble in my learning process.

Just the counter, I'm very grateful with Mr Anchel because the plain and honest way the book was written. This is not only a commercial work, I feel he put best of him to help other in the path of learning darkroom skills, promoting a critical view from the learner.

This honestity is something we can see in other texts, of course, but this book excels in that, IMHO.

Regards

Yes Pere, just in general that one should cross-check... It seems the Anchel has edited the formulas quite well, but what I mean is I have seen stuff published and online with errors... (My source for many formulas is old photo textbooks, and errors do pop up, mainly dilutions, and metric to imperial amounts (and vice/versa)...

Check the pool before you jump in... ;-)

Steve K

[Michael R]

I do own and have read The Darkroom Cookbook. Someone in a thread here said it had some errors that he knew of, so he worried it had others he did not. Still, it has been the basis of my rudimentary understanding of film processing.

In post #8 of this thread, jvo wrote, 'with all due respect, i'd suggest you do some processing rather than reading.. you have enough info from your reading, and the replies here... have some fun!' I see the point, and understand that it may get tiring answering the same questions again and again, but this thread shows my difficulty. Differing opinions and lots of suggestions are confusing (and this is just one thread). Still, it's obvious that I'll have to just make my own decisions in the end, since there are so many perfectly fine choices.

So, concentrated liquid seems like a no-brainer now, and that will take some possibilities off the table. And TF-4 or TF-5 for fixers works for me. Rodinal sounds fine as a developer, but someone elsewhere said it did not do well with lots of agitation. Is that only in some concentrations? I think I'm going to use a drum and constant agitation for processing. Would this be a problem with either Rodinal or the TF fixers?

And a citric acid stop bath sounds pleasant. But then someone mentioned pinholes.

I guess that I feel ready to make actual choices now, if my suggestions here don't raise any issues. Does anyone see any? I plan to use Ilford FP4, and the chemicals I just mentioned, in a constantly agitating drum. I guess the two potential issues I see, based on my reading, are pinholes and Rodinal not liking the drum developing.

I know I keep asking questions, but I do want to know before spending my funds, and before potentially ruining images. And I figure others might have the same questions, and will find the answers by reading this thread.

First, forget the Darkroom Cookbook for now. Use that book as a formula reference (the historical formulae are well edited in the 3rd and 4th editions), but the rest of it contains some bad information. Stick with Kodak's and Ilford's instructions. Your choices of chemicals/materials is fine. FP4 is an excellent film. If you want to use Rodinal, that's fine. HC-110 would be another excellent choice for your application. With these materials/chemicals you will not get pinholes with a stop bath, and "Rodinal does not like drum developing" is unfounded nonsense. Use Kodak's stop bath (acetic acid) or Ilford's stop bath (citric acid). TF-5 (neutral rapid fixer) is fine, but you could also use Ilford Rapid Fixer. Kodak Photoflo or Ilford Ilfotol after the wash. Don't over complicate things.

[Paul Kinzer]

Thanks, gentlemen.

As someone who has a published book in a somewhat similar vein -- a small, specialized, niche audience topic; in my case, astronomy -- I totally understand how errors can enter such a book, as well as how dedicated readers can spot and point them out!

And thanks, too, Michael R. I think my knowledge has progressed far enough to really appreciate specific recommendations.

[interneg]

Main piece of advice seems to be to avoid Sodium Thiosulfate fixes with today's films owing to the heavier use of iodide in contemporary emulsions. Other than that, the only big differences between the Ammonium Thiosulfate fixes is how acid they are - & historically the acidity was only to enable a hardener to be used. C-41 fixes are quite close to neutral pH & add Thiocyanate for better fixing with modern colour emulsions - they're great with BW too & really get the dyes out of Kodak's BW films, however Ron Mowrey has pointed out they can cause issues with less heavily hardened films - Kodak & Ilford are fine. The more neutral fixes will also wash out faster, but that's about it. In sum, pretty much any rapid fix will do the job.

[Pere Casals]

but the rest of it contains some bad information.

Hello Michael,

Just for my information, as I use that book as a reference for me, I'd like to know what bad information has... is there an example ?

Regards

[John Layton]

Regarding the issue(s) of using an acid stop bath prior to an alkaline fixer...I've had great success (for film development in Pyrocat HD) by using a stop bath at one third "standard" dilution...followed by a water rinse prior to using TF-4 fix. As my water is slightly alkaline - this rinse omits any acid carryover to the fix...and the stop is strong enough to relatively quickly and effectively halt development. (if my water were to be neutral to slightly acidic...I might think of adding a bit of alkali to the after-stop rinse).