SHORTER FIX TIME (and at higher dilution too!)

[David Lyga]

Yes, go from your normal cold dev to the warm (same temp as warm fix) stop. And, yes, one shot is most predictable. And if anyone would like to contact me you may do so either at david33x@yahoo.com (remember, I have no computer so there might be a delay of a day or so) or 215.569.4949 anytime. THIS IS OK MODERATOR. Or you may simply post and I will try (ie, not guarantee) to reply. - David Lyga. I also have a photo data sheet that I regularly update on MS Excel format. Again, david33x@yahoo.com and not the email that I initially subscribed to this forum years ago.

 

[Ian Grant]

A point is being missed powder fixers like Kodak's are Sodium Thiosulphate based so slow anyway. this is why they are rarely used dilute for films, but some are for papers. They typically contain around 240g Thiosulphate per litre.

We don't know the temperature coefficient of the particular Sodium Thiosulphate based fixer but the effects of dilution will possibly out-weigh the effects of a higher temperature. Halving the concentration of Sodium Thiosulphate roughly doubles the clearing time (according to Mees) while a 6° C rise in temperature has almost no effect at normal strength and less than 20% at dilution (10% Thiosulphate).

So a rough extrapolation of Mees figures backs up the dilution negates the temperature rise. So it's not more efficient.

Sure there are high speed/high temperature fixers, they were in use for decades particularly for Photofinishing (Sports events) or military/scientific uses but they often used Sodium Thiocyanate instead of or alongside Thiosulphate and had significantly higher levels of hardening either in the films or developer & fixers chemistry.

So a high temperature/short time with dilution of Kodak powder fixer is likely to lead to poor fixation. as well as the needless risk of film damage and probable slight loss in quality.

Ian

 

[Photo Engineer]

David;

I am only stating that you may or may not be correct, but that without tests for retained hypo and Silver, none of us, including you have any proof.

PE