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1. Never ever drop any KI solution into the fix. It will slowly poison it due to the potassium buildup and iodide buildup. Take a 1 ml sample of the fix and add 1 - 2 drops of the KI solution to it. If a heavy yellow ppt forms, then the fixer is bad.

Dispersal of the KI solution into a large tray can give a false negative.

PE

2. Right - you need to dip a bit of the fixer out and test that separately. I failed to mention that earlier.

3. Originally Posted by wogster
No, but it would mean needing to store 3 bottles of fixer (bath one, bath two, concentrate) plus the bottle of KI solution.
Well, the fixer test solution bottle will only be a once or two. It can fit in between the rest. If space is your primary concern, then do what you need to do.

4. Originally Posted by wogster
... for films it's 1:4 so for a 250ml tank it's 50ml of
concentrate, so 20 films per litre,
So you calculate that at a dilution of 1:4, a liter of concentrate
has a capacity of 20 rolls. According to Ilford a liter of their rapid
fix has a capacity of 120 rolls. That's quite a difference; 100 rolls.
Doing a little arithmetic and according to Ilford, 5/6 or a full 83
percent of the fixer is wasted if used as suggested.

If used as I've several times suggested, 20ml of concentrate
in whatever solution volume needed, then 50 rolls. That 20ml
is quite a bit mone than the 8 + milliliters Ilford claims needed.
I used 15ml in a solution volume of 500ml for some time; 66
rolls. A more exact amount may be even less, depending
upon the film and how long you wish to intermittently
agitate. The more dilute the more time.

If one sticks to the same one or two films and wishes to use
fixer frugally fresh each roll then testing for the minimum
needed to thoroughly do the job is worthwhile. Dan

5. Originally Posted by dancqu
So you calculate that at a dilution of 1:4, a liter of concentrate
has a capacity of 20 rolls. According to Ilford a liter of their rapid
fix has a capacity of 120 rolls. That's quite a difference; 100 rolls.
Doing a little arithmetic and according to Ilford, 5/6 or a full 83
percent of the fixer is wasted if used as suggested.

If used as I've several times suggested, 20ml of concentrate
in whatever solution volume needed, then 50 rolls. That 20ml
is quite a bit mone than the 8 + milliliters Ilford claims needed.
I used 15ml in a solution volume of 500ml for some time; 66
rolls. A more exact amount may be even less, depending
upon the film and how long you wish to intermittently
agitate. The more dilute the more time.

If one sticks to the same one or two films and wishes to use
fixer frugally fresh each roll then testing for the minimum
needed to thoroughly do the job is worthwhile. Dan
Everybody seems to be neglecting an important point, arguing against my methodology. Maybe I'll take 52 rolls worth of photos in a year, half of that is (gasp) digital, so that leaves 26 rolls, 1/4 of those are going to be colour film, for one reason or another, so maybe 19 to 20 rolls B&W in a good year. Okay so I can use complex methods, to use a lot less fixer, and then end up tossing a half bottle because it's expired..... I haven't made silver prints in almost a quarter century. I closed the darkroom in 1984, I have done a little film processing here and there in the last 3-4 years, then scan the result. If I want a nice big silver print, I'll take my negative to a lab.....

6. Originally Posted by wogster
Everybody seems to be neglecting an important point,
arguing against my methodology. ...maybe 19 to 20 rolls
B&W in a good year. ... and then end up tossing a half bottle
because it's expired.....
I too don't like to watch good chemistry go bad. I've mentioned
in post 17 this thread the low volume of film I put through. So
I'm back to using sodium thiosulfate. Sodium thiosulfate is a
slower fixer but is a dry, lasts who knows how many years,
granular fix concentrate.

A good 1/2 ounce, 16 grams, of the anhydrous in a solution
volume of 500ml will do to fix one 120 roll of Across. The same
amount should do for a few other films; apx 30 rolls per pound.

Agitate the first minute then a few inversions each minute
there after. I've not checked for exact times but allow
a good ten minutes. Toss when finished.

Need a source? Photographer's Formulary. Dan

7. Originally Posted by dancqu
I too don't like to watch good chemistry go bad. I've mentioned
in post 17 this thread the low volume of film I put through. So
I'm back to using sodium thiosulfate. Sodium thiosulfate is a
slower fixer but is a dry, lasts who knows how many years,
granular fix concentrate.

A good 1/2 ounce, 16 grams, of the anhydrous in a solution
volume of 500ml will do to fix one 120 roll of Across. The same
amount should do for a few other films; apx 30 rolls per pound.

Agitate the first minute then a few inversions each minute
there after. I've not checked for exact times but allow
a good ten minutes. Toss when finished.

Need a source? Photographer's Formulary. Dan
I guess one of the issues is that even from dry, you can't really mix a 1/4 bag, because you may get more of one ingredient then another. There are other things in fixer then just the Hypo. If you get a bag of each chemical from Osama's chemical supply co. though, and have a scale, you could mix smaller batches.

8. Originally Posted by wogster
There are other things in fixer then just the Hypo.
Plain fixer is nothing more than ammonium or sodium thiosulfate.
A preservative is usually/always added to packaged or bottled fixers.
If using the fix one shot and it not be left to age then nothing more is
needed than the ONE chemical. Spoon up fresh fix each roll. For film
and paper I mix same day as processing. One use and down the
drain chemistry; hold the preservative. Ph modifiers and
buffers may also be omitted for most purposes. Dan

9. Originally Posted by dancqu
Plain fixer is nothing more than ammonium or sodium thiosulfate.
A preservative is usually/always added to packaged or bottled fixers.
If using the fix one shot and it not be left to age then nothing more is
needed than the ONE chemical. Spoon up fresh fix each roll. For film
and paper I mix same day as processing. One use and down the
drain chemistry; hold the preservative. Ph modifiers and
buffers may also be omitted for most purposes. Dan
Okay, so I can go to Osama's chemical and explosives company, order up a 5kg pail of plain sodium thiosulfate (hypo), mix 16g in a litre of water, and I have fixer, so I guess for a roll of film in 250ml of solution that would be 4g of powdered Hypo, per roll, hmmm, at 4g per roll the pail would be good for 1,250 rolls, at 20 rolls per year that would give me enough fixer to get me half way through the year 2070, fine except I will be 109 that year, don't think I will be taking many photos at 109 years of age, even if I am still here...... I wonder if they will sell it to me 1kg at a time

take me 312 years to use up the pail. Somehow I don't think I will be shooting much in

10. Don't worry, that pail of fixer crystals will probably be bad long before then.

PE

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