More on C41 fix for B&W

[rowland_mowrey]

I have been working on chemistry related to the C41 RA Fixer with B&W

films, and find that with incorrect dilution (using it too

concentrated), I can reticulate some B&W films.

 

So, this is a warning.

 

Use of C41 RA Fixer, without proper dilution, may severely reticulate

some B&W films depending on film, dilution and temperature.

 

Ron Mowrey

[frank.schifano]

Ron:

 

I've been using C-41 fixer on films and papers for a while, but haven't seen any reticulation problems because of it. I use it mixed as directed on the bottle and keep temperatures across all my chemicals within 1 degree of 20 deg. C. I have not used it with any of the soft emulsion films. Is that where you've noticed the problem?

 

For the next working solution batch, I plan to dilute the standard strength solution with an equal part or water. I expect fixing times to elongate and capacity to halve. Because you can run so much film or paper through a given batch of standard strength solution with very little diminution of fixing power, I'm concerned about a build up of hard to wash out fixing byproducts, especially with fiber papers, causing problems later on.

[rowland_mowrey]

All please note:

 

I said C41 RA fixer.

 

This precaution does not apply to the standard C41 fixer.

 

Ron Mowrey

[discpad]

Ron, this would be an issue with the fixer attacking the actual gelatin. Are you seeing reticulation with Kodak and Fuji B&W films (do they use the same, robust gelatin as color film to withstand 100F processing?); or are you seeing it only with Eastern European (and perhaps Ilford) films as well?

 

Please tell us which films you've seen this reticulation!

 

Thanks!

Dan

[rowland_mowrey]

I have seen reticulation with EFKE and Ilford films. I am going to test it with EK films ASAP, but I only have some sheet film right now. I have to get another 35mm roll of EK B&W, as I used mine all up. I have no Fuji B&W films here.

 

It only happens if you use the fix too concentrated. It does not happen at normal working strength. This would work out to about the same concentration of hypo as found in normal B&W fixes.

 

It does not happen with color films at all.

 

Ron Mowrey

[discpad]

Our chemistry guru Ron wrote, "I have seen reticulation with EFKE and Ilford films."

 

 

...And that makes sense: Efke (and Bergger) are notorious for their soft emulsion scratching... And Ilford, since they don't make color film, would be a good candidate for weaker gelatin, too.

 

 

If Kodak is using the same gelatin for their B&W photo films as they use for color, then the stronger rapid access fixer shouldn't be a problem.

[rowland_mowrey]

Dan;

 

It may depend on hardener level or on the presence of polymers more than it does on anything else.

 

IDK yet.

 

Ron Mowrey

[larrydressler]

Darn I guess I will stick with what I have untill I can't get it any more. though that is nice to know. I tryed to make some film reticulate recently and it was FOMA not Forte. I will use the Forte next time. Also Foma is changing to ADOX in name soon in some Countries now that Agfa is dead.

 

Long live ADOX

Larry