Powder Fixer: can I split the powder into smaller bags

ts1000 · May 15, 2021

I a new to film developing.
Bought a powder fixer (from ultrafine) see attached.
It is meant to mix 1 gallon. But I need to process just 2 rolls of film every 1.5 months or so (sofar).
I will not be using the 'double bath method'.
My film is always going to be Ilford HP5+ ISO 400, 35mm, shot at box speed.

Is it possible to split into content of the bag into smaller bags (and just mix a small portion of the powder) ?
I do not mind mixing every time before I develop.

If yes, what should be the weight of the splits, and are there any specific storage precautions (I plan to just have the powder in freezer plastic bags).

I searched the forum but did not find any posts on splitting.

-- --
The bag with powder weights 708 grams. Without powder 17 grams.
I also measured second bag I had, and that one is 713 grams.
This fixer seems to be 'non-hardening', it has boric acid.

ChristopherCoy · May 15, 2021

From what I've learned after recently researching the same question, no. Powdered chemicals contain crystals of different weights and settle in packaging and shipping. If you split it into multiple bags, there's no way to ensure that equal amounts of the necessary powdered components get into each bag.

MatthewDunn · May 15, 2021

If you are going to process that infrequently, I would either buy something in a 1L package (like ID-11) or just go with something like DDX which can be made up at a moment's notice on demand.

MatthewDunn · May 15, 2021

But yes, general recommendation is that you will not be able to ensure chemical consistency across "segments" of your 1G pack - better not to split.

ts1000 · May 15, 2021

Thank you for the replies. I read about D-76 developer not being able to maintain chemical consistency if powder is split. But did not read the same about the fixer in powder form.
This is good to know that the same constraint applies to the powder fixer.

ChristopherCoy · May 15, 2021

ts1000 said:
This is good to know that the same constraint applies to the powder fixer.

It probably applies to any powdered chemical compound.

MatthewDunn · May 15, 2021

ts1000 said:
Thank you for the replies. I read about D-76 developer not being able to maintain chemical consistency if powder is split. But did not read the same about the fixer in powder form.
This is good to know that the same constraint applies to the powder fixer.

This is true of all powdered chemistry for the reason @ChristopherCoy points out - different chemicals have different weights and settle. Simply taking "half" (or other portion) of the volume without taking into consideration the settling is an invitation to frustration and hair-pulling.

MattKing · May 15, 2021

All is not lost though.
Fixer is intended to be used and re-used over a period of time. So there is a decent chance that you can make that gallon last for a minimum of six months, and probably longer.
I would suggest mixing it up and then dividing the gallon into four quart containers. Glass is best, although fairly heavy soda pop plastic can works as well. Try to have each one as full as possible, because any air above the liquid will contribute to deterioration. Make sure the caps seal well. It is better to have three containers filled to the brim, and the fourth ready for immediate use.
You can probably use (and re-use) the contents of each container for three months, and then go to the next.
Particularly as the fixer gets older, you should test its activity using a clip test. Here is a link to a description I posted about how to do a clip test. For now, don't worry about the second half of the article, because your volumes don't require that: https://www.photrio.com/forum/resou...ixing-procedure-for-black-white-negatives.75/
By the way, APUG is the former name for this site.
Most likely that gallon of fixer has the capacity to fix a lot more film than you will use it for. So don't worry about using it for more film .

ts1000 · May 15, 2021

Thank you.
My developing tank is the aluminum style for one roll of 35 mm. I measured that it takes about 250ml of water (slightly more)

Does it mean I will need to fill it in with 250ml of the mixed fixer solution?
(I read that I would have to fill it in fully with D-76 stock (mixed solution), so I am assuming the same applies to the fixer)

I am somewhat confused by US oz vs Imperial oz, when folks suggest that many Oz, so sticking with milliliters.

Apologies for naïve questions.

MattKing · May 15, 2021

ts1000 said:
Apologies for naïve questions.

No apology is ever necessary for asking a question about something you don't know or understand!

ts1000 said:
I am somewhat confused by US oz vs Imperial oz, when folks suggest that many Oz, so sticking with milliliters.

I don't think that there are many here who use imperial ounces when they talk about volumes. Most of those who still use ounces are from the USA, and never took to metrication in the photography world. But even those are probably happy with milliliters.

ts1000 said:
My developing tank is the aluminum style for one roll of 35 mm. I measured that it takes about 250ml of water (slightly more)
Does it mean I will need to fill it in with 250ml of the mixed fixer solution?

Most likely, your tank is stainless steel, as aluminum doesn't play well with some darkroom chemicals.
Check to see if there is a capacity recommendation engraved on the tank. Or a brand name, because someone here might have the same tank.
The amount of fluid you want is enough to fully cover the reel with the film in it, but not too much, because there needs to be a bit of air above to permit sufficient fluid movement during agitation. 250 - 300 ml is typical for that type of tank.
And yes you should fill the tank in the same way that you fill it with developer. The difference is that the fixer is designed to be re-used, and many developers are used "one shot".

ts1000 · May 15, 2021

@MattKing and others, thank you for the follow ups. I mixed the full bag now (also updated my original post with weights, if anybody was curious).

grahamp · May 16, 2021

When I was doing analytical geology it was a common problem where stored ground rock powder would stratify due to the density and shape of the mineral grains and the influence of vibration and thermal expansion/contraction. We had to take the storage jars (never more than 3/4 full) and put them on a machine to oscillate them in a sort of three dimensional figure eight path. A couple of hours of this and the powder was homogenized to parts per million level.

We would often start with kilos of rock and have to reduce it to a representative sub-sample after grinding. This usually involved splitter boxes or rotary sample splitters. The aim being to get an even separation by mass/volume. It was surprisingly effective, though the sub-samples were not identical at our level of detection. Something fairly simple like fixer power could be split manually and function fine, but it is not worth the mess and effort for something that keeps well when mixed. Complex combinations, like developers where some components are orders of magnitude different than others by mass will not split using simple manual methods. You would need large quantities to approach homogenous splits, and multiple passes to get there.

Bear in mind I was doing this in a lab where we could analyse splits and document our methodology, thus validating our results. I would not think of doing this at home - I do not have the tools, and neither the time nor the desire to do it.

ts1000 · May 16, 2021

@grahamp Exactly. I looked at the material safety sheet of the fixer, and some components there were just like 5% of the overall package.
So unless each grain had proportionally equal amount of the whole content, there is no amount of shaking that I could do to ensure the equal split.
So I went with the recommendation here, and just mixed the whole 1 gallon.

Finally developed and scanned it!. This was 12 years in the making (bought epson scanner 12 years ago or so).

Finally can share some images. I think I overdid the stop-bath (I used 5 ml for 295 ml volume)
But overall, I surprised my family members, that it worked, and i was able to follow through

Konica AutoReflex T2 with 50mm 1.4 (shot at f8 or f11), Ilford HP5+ at box speed, D76-ultrafine at 14 min, Kodak stop bath at 5ml for 295 ml of water, Fixer-ultrafine-powder, no name stainless steel dev tank for 1 roll (made in Japan).

mshchem · May 16, 2021

grahamp said:
When I was doing analytical geology it was a common problem where stored ground rock powder would stratify due to the density and shape of the mineral grains and the influence of vibration and thermal expansion/contraction. We had to take the storage jars (never more than 3/4 full) and put them on a machine to oscillate them in a sort of three dimensional figure eight path. A couple of hours of this and the powder was homogenized to parts per million level.

We would often start with kilos of rock and have to reduce it to a representative sub-sample after grinding. This usually involved splitter boxes or rotary sample splitters. The aim being to get an even separation by mass/volume. It was surprisingly effective, though the sub-samples were not identical at our level of detection. Something fairly simple like fixer power could be split manually and function fine, but it is not worth the mess and effort for something that keeps well when mixed. Complex combinations, like developers where some components are orders of magnitude different than others by mass will not split using simple manual methods. You would need large quantities to approach homogenous splits, and multiple passes to get there.

Bear in mind I was doing this in a lab where we could analyse splits and document our methodology, thus validating our results. I would not think of doing this at home - I do not have the tools, and neither the time nor the desire to do it.

This is very good information. I worked in a lab in my younger days. We would take samples of (as uniform as we could make it) granular materials, animal feed additives. We would strive for uniform particle size. Even so we used sample splitters and would reduce kilogram quantities to extremely fine powder (US Sieve 100 mesh, ie nylon stocking) to allow us to run chemical tests.
If someone wants to divide something like powdered fixer, I'm not recommending it, but consulting older texts, early 20th century, might be helpful. I have some of my father's old pharmacy books from the 1930's. There's a lot of information about this sort of thing.
Firstly, one can't just pour something like fixer out as you need it. In lieu of a splitter, you can mound the material up on a clean surface and using a wooden ruler cut the mound into half, then quarters.
Easier to make 4 full quart bottles of fixer solution with pure water. Exclude air, these will keep well at room temperature.

Don_ih · May 16, 2021

Best bet: buy some rapid fixer. Foma sells a small bottle of it (500ml, I think).

mshchem · May 16, 2021

Don Heisz said:
Best bet: buy some rapid fixer. Foma sells a small bottle of it (500ml, I think).

+1

RalphLambrecht · May 16, 2021

ChristopherCoy said:
From what I've learned after recently researching the same question, no. Powdered chemicals contain crystals of different weights and settle in packaging and shipping. If you split it into multiple bags, there's no way to ensure that equal amounts of the necessary powdered components get into each bag.

I's much easier o prepare it all and then divide the liquid into smaller bottles.

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