Kentfix Wrong Dilution?

[elias_roustom]

I mixed up the mixing instructions: 3L of water, mix in powder, fill to 3.8L. The instructions for Kentfix

are in graphical form, so I thought I needed to mix the powder with 3.8L of water, as opposed to end up

with 3.8L... rookie error. Is this fixer wasted now? It takes a good 5 minutes to clear a piece undeveloped

film in the solution. at 7 minutes it seems to have worked fine for a roll of 120 film - or should I re-fix

and rinse it? Thanks for any help.

[bgelfand]

How much solution did you end up with? Take the ratio of 3.8 to the volume you have. That is the fraction of full strength that you have.

 

As an example, if you end with 4 liters of solution you would have

3.8/4 = 0.95 or a 95% solution.

 

5 minutes sounds a bit long for 95% new solution. Are you sure it took that long? Clearing time can be deceiving. The best way I have found is to put a drop of the fix on the emulsion side of the film and let it sit for a minute or two. Then immerse the whole piece of film in fixer and start your timer. The place on the film with the drop will clear first, giving you contrast to see when the rest of the film clears.

[frank.schifano]

Don't worry about it. Your mixing error is not a big deal and won't make a whole lot of difference. In short, don't throw it out, it's perfectly ok to use. I'm pretty sure that Kentfix is a sodium thiosulfate fixer and these do take quite a bit longer to work than the ammonium thiosulfate based, rapid fixers. Five minutes to clear a piece of undeveloped film is not unusual for sodium thiosulfate fixers. Brooks' testing method is a sure thing, and I do the same myself. Just remember that to be safe, total fixing time should be 2x the clearing time. ...and don't forget to agitate!

[elias_roustom]

Thank you all for those very helpful responses. Especially for the 2XClearingTime rule of

thumb reminder (I'd forgotten about that). Working with Ilfofix for so long, I got used to 30

second clearing times in fresh 1+4 dilution. I'll use 10 minutes for my roll film until I've used

this stuff up. There's no such thing as over-fixing is there?

[bgelfand]

Yes, you can over-fix, but 10 or 12 minutes is not over-fixing. If you leave it in the fix for hours, that is over-fixing. You might not have much image left. <grin>