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Calbe A300 fixer
#1
I'm wondering about the chemical components of A 300, does it contain acid so is it a hardening fixer?



This information isn't available in the Calbe technical papers, only dangerous components are listed there.



Thank you

Jukka
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#2
Hi Jukka,



hardening fixers may contain acid components or not. Acid components have absolutely nothing to do with hardening capabilities. Normal fixers are acid, whether "rapid" or not. Only fixing baths for C41-processes are neutral and require the use of an acid stop bath.



A300 is a fixing agent based upon sodium thiosulfate, thus not a modern "rapid fixer". It consists of sodium thiosulfate and sodium sulfite for conservation purpose. Nothing else added. A cheap, simple, traditional recipe.



Hardening fixers have some formaldehyde salts added and are based on ammonium thiosulphate. Most commercial fixers (except noted) are non-hardening fixers. Even rapid fixers are non-hardening as both paper and film are very much pre-hardened today (except Adox/Efke films).



Sorry for my rotten english. I'm much better in chemistry than in english:-)



Best regards,

Franz
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#3
Thank you Franz!



The reason why I asked, I have been in love with Classic/Forte films and had previously used Agfa Agefix with these films with satisfying results even if that fixer is a non-hardening one. Now I'm looking for a simple universal equivalent for Agefix and was wondering if A300 would be as kind to my "dear films" as Agefix was.



Thank you for the correction about the role of acids in fixers - I looked at some recipes and the hardening fixers happened to have acetic acid etc listed so that's where I got the idea.



No need to apologize about your English!



Cheers from Finnland,

Jukka
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#4
[quote name='cfb_de' timestamp='1152739081' post='8024']

(...) A300 is a fixing agent based upon sodium thiosulfate, thus not a modern "rapid fixer". It consists of sodium thiosulfate and sodium sulfite for conservation purpose. Nothing else added. A cheap, simple, traditional recipe. (...)

[/quote]



I don't know if they ever changed the recipe of their A300 fixer, but as far as i know, it's a fixer based on ammonium thiosulphate (as you can read in the [url="http://www.calbe-chemie.de/prod/pdf/A%20300%20en.pdf"]product information[/url]; i guess the letter A in the product name also indicates that):



Zitat:(...) This light in weight powder fixer, based on Ammonium thiosulphate, (...)



Though I admit the A300 is a very slow fixer, like fixer based on sodium thiosulfate, if you use the amounts of water given in the manual.



Sorry for writing on this old thread, but this is still a relevant result on Google and I just wanted to mention/correct this.
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#5
Die Rezeptur wurde 2010 geändert!

The recipe was changed (much to our dissatisfaction without notifying anyone).



Grüße,



Mirko
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#6
[sup]What does it consist of now? Sodium thiosulfate or ammonium thiosulphate? I'm confused.[/sup]
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#7
Warum ist das überhaupt wichtig? Bei Entwicklern ist klar, dass verschiedene Entwicklersubstanzen auch deutlich unterschiedliche Ergebnisse liefern. Aber bei Fixierern? Natürlich gibt es Unterschiede hinsichtlich Verarbeitungszeiten, Ergiebigkeit, Haltbarkeit und Auswässerungsgeschwindigkeit; was die Ergebnisqualität anbelangt, habe ich dagegen keine Unteschiede festgestellt. Habe ich da bisher etwas übersehen?



(Why do you think this is important? Of course processing times, yield, useful life and speed of washing may differ; however, in terms of result quality, I have never noticed any difference. Is there anything that I may have overlooked?)



tepe
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