Mixing from two-part powder (Fuji Papitol)

[VPooler]

Hello!

I recently purchased some Fuji Papitol 2-part powder for experimenting purposes (E6 without E6 chemicals). Now, I am no stranger to mixing from powders, even 2 or more part powders. Just dump the contents in a jug of water and stir properly. But the packets are in this case for 8 liters which is more than I need. The package suggests mixing with 4L of water and dilute work solution from there. But 4L of stock is too much to mix and store + the developer should last me a long time. I don't want to mix up a whole batch for a few rolls and discover that it has gone bad the next time I need it.
I was thinking of opening up the packages, pouring them into separate containers and shaking them up like a bi**h with rabies, then weighing the appropriate amount of powder and mixing up as much work solution as I need.
The other idea would be mixing up a highly concentrated mix - emptying those packets into just 1L of water and diluting as I go. For how long could that keep?

Thanks for any advice in advance!
Vallo

 

[Gerald C Koch]

Powder mixes settle out and are no longer uniform. Even if you try to stir the powder to mix it this may not be effective. Manufacturers like Fuji use special mixing machines to ensure that the powder is well mixed before it is sealed into bags. But shaking during transit causes the individual components to separate again. So NO you cannot mix part of a bag.

If you attempt to dissolve the developer in less than the 4 liters of water as Fuji suggests will result in not all of the powder dissolving. So you cannot make up a very concentrated mixture.

 

[pentaxuser]

. Manufacturers like Fuji use special mixing machines to ensure that the powder is well mix before it is sealed into bags.

/QUOTE]

What does the Fuji machine do that a very thorough hand shaking doesn't. I may be naive but I'd imagine that mixing is mixing and its the extent that counts not the machine. A bit like the difference between crushing grapes with a machine and doing so by feet. Feet just take longer or at least can't handle the same volume of grapes but do the same job.

Not trying to be a smarty-pants but presumably the Fuji powders can't distinguish between the Fuji mixing machine and shaking by hand can they? :confused:

If there is a vital difference between the two methods whereby shaking or mixing with a ladle or slow speed kitchen hand-mixer cannot replicate what the Fuji machine does then can you enlighten me and the OP?

Thanks

pentaxuser

 

[Arctic amateur]

Shaking a mixture of granular materials will tend to move the small grains downward and the large grains upward. Shaking powder is not like shaking liquid.

 

[Rudeofus]

Isn't Papitol a paper developer? Are you sure it is well suited for E6 FD? Why don't you try some liquid PQ developer instead, which you can use in higher than normal concentration to match regular E6 FD activity?

 

[VPooler]

Isn't Papitol a paper developer? Are you sure it is well suited for E6 FD? Why don't you try some liquid PQ developer instead, which you can use in higher than normal concentration to match regular E6 FD activity?

The Japanese seem to have perfected doing E6-ish process with Papitol and C41. The convenience of having standardized process.

 

[Xmas]

. Manufacturers like Fuji use special mixing machines to ensure that the powder is well mix before it is sealed into bags.

/QUOTE]

What does the Fuji machine do that a very thorough hand shaking doesn't. I may be naive but I'd imagine that mixing is mixing and its the extent that counts not the machine. A bit like the difference between crushing grapes with a machine and doing so by feet. Feet just take longer or at least can't handle the same volume of grapes but do the same job.

Not trying to be a smarty-pants but presumably the Fuji powders can't distinguish between the Fuji mixing machine and shaking by hand can they? :confused:

If there is a vital difference between the two methods whereby shaking or mixing with a ladle or slow speed kitchen hand-mixer cannot replicate what the Fuji machine does then can you enlighten me and the OP?

Thanks

pentaxuser

Well Id assume different ie that Fuji don't bother to mix up the powders instead using a robot weighing machine...

Unifying powders difficult.

You could try if you want or use a set of scales and individual chemicals for the volume of liquid you want.

But then you are limited to published formula's.

 

[Gerald C Koch]

Simple stirring of a mixture of powders of different particle size tends to actually separate them according to particle size. Therefore commercial machines tumble the mixture. The mixing machine that I am familiar with consists of two cylinders joined at one end to make a V-shaped container. This container is rotated from two points halfway down the "legs" of the apparatus.

http://www.dryblenders.com/

Insuring that dry mixes are of uniform composition is not a simple task and much research has been done on machine design.

 

[Rudeofus]

The Japanese seem to have perfected doing E6-ish process with Papitol and C41. The convenience of having standardized process.

You could try the following: add the contents of the whole package to 1 - 1.5 liter of warm water, stir well, then let it sit for a while. Maybe there will be some solid residue that will not dissolve. If so, filter out whatever didn't dissolve and dry the filter with these residues, then dissolve these residues in 100 ml (or more if needed) warm Propylene Glycol, which is cheap and available in any well stocked pharmacy. This will give you at most two concentrates of unknown composition, but you know that in combination these two will give you the original developer, and these two concentrates can be trivially subdivided.

The rationale behind this is this: the most likely compounds to exhibit difficulty in fully dissolving will be the metaborate and the hydroquinone, so these two will form most of the residue in your filter paper (if there is one to begin with). As it just so happens, these two compounds dissolve very well in Propylene Glycol. Since some of the Hydroquinone will be dissolved in the water concentrate, it will protect whatever primary developer is used in Papitol (Phenidone?)

Before you commit the whole pack of powder to this, I recommend you try this with a small fraction of your powder and solvents.

 

[VPooler]

How well would a standard developer keep? Maybe I could decant it into smaller bottles and use up as I go?
Funny thing is that I have a load of bulk chemicals, I could probably mix up Papitol from scratch if I only had the formula.

 

[pentaxuser]

Thanks for the explanation Gerald. I can see how it is vital that the right amount of each ingredient goes in and why it is thoroughly mixed which no doubt such a machine does but I am still having difficulty with what the blender/mixer does that a less sophisticated mixer cannot achieve.

Once the mixture which may have several component parts is in the two bags then of course simply mixing the complete contents two bags into water ensures that all the necessary ingredients are there in the right quantities but having to use both bags completely seems to imply that settlement will occur which cannot be easily undone by shaking, hence the reason why all the content must be used.

However this then begs the question of whether, if settlement does occur, then the mixing machine's main function is to measure the ingredients correctly rather than mix them.

Either there is settlement/separation which not even a sophisticated mixer can correct so all the bags' contents must be used or the mixer ensures that once mixed no settlement occurs in which case weighing each bags contents into smaller sections would work or only a specially designed mixer, not available to the user, can once again mix the settled contents correctly which brings us back to quite what such machines as you link to do which hand mixing or small kitchen whisking cannot do.

I have seen posters claim that they have been successful with re-mixing and subdividing the bags for other developers where two bags were involved. They may of course have been lucky and whatever they were mixing might have been easier

pentaxuser

 

[Rudeofus]

How well would a standard developer keep? Maybe I could decant it into smaller bottles and use up as I go?
Funny thing is that I have a load of bulk chemicals, I could probably mix up Papitol from scratch if I only had the formula.

Since this is a paper developer, it would surprise me quite a bit if it contained very odd ingredients. The MSDS for part A lists 60-80% Sodium Sulfite, 18% Hydroquinone, 1-5% Potassium Bromide, 1-5% of some Tetraphosphate as sequestering agent for water hardness, 1-5% water, 2.2% Metaboric Acid, and 0.5-1.5% Monosodium Phosphate. Since a paper developer powder would need enough Metol to be listed in the MSDS, I assume that small amounts of Phenidone or Dimezone-S are used as primary developer. Papitol part B contains, according to its MSDS, only 80-100% Sodium Carbonate and 10-20% water. Since Phenidone/Dimezone-S content determines developer activity, you should be able to determine the correct quantity for you purpose with little effort.

If you can scratch mix, why mix Papitol and not E6 FD? See (there was a url link here which no longer exists) and here for recipes, you can mail order all the listed ingredients except the Thioglycerol from Suvatlar and Keten, both ship at least within EU boundaries AFAIK.

 

[Rudeofus]

I have seen posters claim that they have been successful with re-mixing and subdividing the bags for other developers where two bags were involved. They may of course have been lucky and whatever they were mixing might have been easier

Modern photographic papers have builtin contrast, which means as long as your print developer is not completely out of whack you will get indistinguishable prints. This means that even if powder developers split up into parts with different ingredient ratios, it won't matter much.

User VPooler wants to develop E6 slides with this developer, and in this case ingredient ratios have direct impact on the result.

 

[VPooler]

I have studied the E6 recipe and it is just not economically feasible to mix it myself. However, what came into my mind is the developer's activity - it develops in 90 seconds. Now, I have a big book of B&W recipes, I could possibly look up a formula for a developer that has similar activity and try it out. I have some half a kilo of metol and a bit less of HQ at my disposal, among with washing soda, bromide and sulfite - I mix my own color developer that way.
Or I will finally cave in and mix the whole lot up and pray that it would keep for about 4-6 months it takes me to use the whole thing up.

 

[Rudeofus]

I have studied the E6 recipe and it is just not economically feasible to mix it myself. However, what came into my mind is the developer's activity - it develops in 90 seconds. Now, I have a big book of B&W recipes, I could possibly look up a formula for a developer that has similar activity and try it out. I have some half a kilo of metol and a bit less of HQ at my disposal, among with washing soda, bromide and sulfite - I mix my own color developer that way.
Or I will finally cave in and mix the whole lot up and pray that it would keep for about 4-6 months it takes me to use the whole thing up.

The only component that is really expensive in E6 FD is the Hydroquinone Monosulfonate, and even that can be obtained from Suvatlar at moderate cost, especially if you order larger amounts (just ask for prices). You can leave out the Potassium Iodide, it probably won't matter much if you then cross process with C41 chemistry anyway. You can substitute the Dimezone-S for adjusted amount of Phenidone (or use Stefan Lange's Chromebrew formula, it works well), and Phenidone can be ordered from Keten at very reasonable cost. If you use distilled water for mixing your E6 FD, you can leave out the sequestering agent(s).

If you really want to avoid the Hydroquinone Monosulfonate, there is a recipe based on Hydroquinone here. It is said to give inferior results to the real formula.

 

[VPooler]

The only component that is really expensive in E6 FD is the Hydroquinone Monosulfonate, and even that can be obtained from Suvatlar at moderate cost, especially if you order larger amounts (just ask for prices). You can leave out the Potassium Iodide, it probably won't matter much if you then cross process with C41 chemistry anyway. You can substitute the Dimezone-S for adjusted amount of Phenidone (or use Stefan Lange's Chromebrew formula, it works well), and Phenidone can be ordered from Keten at very reasonable cost. If you use distilled water for mixing your E6 FD, you can leave out the sequestering agent(s).

If you really want to avoid the Hydroquinone Monosulfonate, there is a recipe based on Hydroquinone here. It is said to give inferior results to the real formula.

Thanks for the link! I will try it out one day. And I will be processing my chromes in ECN-2 developer, it has the neccesary CD3 and since I shoot MP stock anyway, I'll have always some at hand. But now I guess I will just mix that 4L of Papitol up and see what happens!

 

[Gerald C Koch]

What is not apparent unfortunately is that there are baffles inside the mixer chambers which direct the flow of the powder. There is a lot of technology involved in their design. Some mixers use a random type motion to further insure proper mixing. In a typical batch the mixer runs for 30 to 40 minutes.

The problem of mixtures "unmixing" themselves during transit is also a problem for analytical chemists which have to be assured of a representative sample. So samples will be taken from say certain barrels chosen at random and from random positions in the barrels. Texts on analytical chemistry usually have a chapter on how to obrain samples properly.

The main problem with powders is vibration or any repetitive motion. This causes larger particles to move to the surface and smaller ones to the bottom. Since powder chemicals are usually of different sizes a certain chemical like hydroquinone may rise to the surface while sodium sulfite or carbonate may move to the bottom of a container. Interestingly it is particle size rather than weight that is more important in this respect. Years ago when developers were supplied in metal cans the unmixing was sometimes visible when the can was opened.

If one has ever spoken to a New England farmer he will talk about each year's new crop of rocks in his field. Repeated freezing and thawing makes the rocks rise to the surface. The same principle at work here.

I am not saying that it is impossible to re-mix powders but it does require both a bit of luck and a knowledge of how to do it properly. As I said previously merely stirring the powder will not work.

 

[pentaxuser]

Your most recent post, Gerald, suggests that settlement might and probably does occur over time but complete mixing of all the contents means that such settlement doesn't matter. However this also means that subdividing the powder will be at best risky(it might work by chance if everything remains as it was when the machine mixing finished but this is an unlikely scenario ) and at worse will result in failure based on what is needed when using it as a developer for E6 film based on Rudeofus' post

In other words some settlement may occur but this won't matter if all the contents are mixed but the chances of subdividing and being successful are remote.

Subdivision of a two bag B&W developer for a B&W film has a much larger margin for error and presumably if the bags are shaken well before subdivision then the chance of success are good.

pentaxuser

 

[Gerald C Koch]

Getting a uniform and reliable product to the customer is not easy. With Xtol Kodak tried a new method where the chemicals were added individually to each bag. However they soon began to get complaints about the 1 liter bags. The 1 liter bags produced inconsistent results. After much study Kodak determined that the amounts of some of the chemicals for the 1 liter bags were too small to reliably measure with uniformity. So the 1 liter size was discontinued. The 5 liter bags were large enough so the problem did not exist for them.

 

[Rudeofus]

Allow me a brief and completely off topic comment about powder mixing: as Gerald mentioned above, the smaller particles tend towards the bottom while the bigger particles rise to the top. This sounds counterintuitive at first, since larger particles have greater density. Why would they rise to the top? Answer: Entropy. Smaller particles have a greater chance to slip into small cracks and holes towards the bottom and will more likely end up there, gravity and energy minimum be damned.

Why did I mention this? Powder mixing is highly counterintuitive, and the great pain professional powder mixers go through suggests that simple intuitive home brew methods won't work reliably.

 

[tokam]

You can verify the entropy effect at home yourself.
Take a bag of potato chips, crush them lightly, shake and then open.
Guess where the big chips are and where the crumbs will be....:munch: