New film developer idea (all powder!)

I’m setting up a film processing station in my new commercial photo studio. I think I’m going back to all powder formulation, like I used to with DS-1 and DS-2. For small scale film processing, powder formulation offers more advantages than liquid concentrates, including long keeping properties. I’d rather weigh powder mix than viscous stock.

I’d probably formulate like this:

Part A:
ascorbic acid
Phenidone (or Dimezone S)
one or more water soluble polymers (cellulose derivatives, vinyl derivatives, and of course polyvinylpyrrolidone) and/or sugar alcohols (sorbitol, xylitol, etc).
any other additives

Part B:
sodium sulfite
borax
developer stabilizer additive

The only tricky part here is how to ensure uniform mix and prevent segregation in Part A. I think one or more water soluble polymers with suitable molecular weight and particle size can be used to “dilute” Phenidone first, wherein the Phenidone and polymer form cohesive aggregates. This is then mixed with the rest of ingredients in Part A. With this level of care in formulation, it is okay to just stir the jar before use.

Some of the water soluble polymers are actually known to improve image quality. Viscous developers are known to increase accutance and reduce granularity, although incompatible with spiral tank processing. I’m probably going to use polymers that are not viscous for this project, but something that has other effects, such as lower fog level and cleaner highlights. In the past, I experimented using several kinds of polymers in liquid concentrate stocks, but these polymers do not dissolve well in a concentrated sulfite solution. So, I often had to add them to the working solution. Powder formulation can just solve that problem altogether.

Another advantage of powder formulation is that we don’t need glycols and other solvents, and don’t need to handle viscous liquids. About the only and small negative is that I have to give up my favorite ethanolamine mix and go back to Borax.

If this approach works, I think it’s just a matter of stirring powder mix A in a jar, take 6 grams, take 50g of B, dissolve in a liter of cold tap water, adjust the temperature and it’s ready to go. (Numbers are just made up but they are realistic range.) This will be easier to dissolve than D-76 (stuff will dissolve while loading films into tank). I’d probably keep mix A in a vacuum jar to prevent moisture caking and oxidation.

Added bonus is that I can have a Part C, which can be used in place of Part B, to make a different developer. I’m most likely making Part B for fine grain (400+ speed films) and Part C for accutance (100 speed films), just like what I used to do with DS-1 and DS-2.

What do you guys think?

Won't you just run into the old issue of particle separation due to bulk density? I suppose if your polymer can be coated uniformly then you have a chance of it working.

How's this idea - find a matrix that is soluble in both solvent and water and then dissolve your phenidone and ascorbic into it with the solvent. Pour the solution out into a tray and let the solvent evaporate. Then grind the matrix to a fairly uniform particle size so that it quickly dissolves in water. Then you can pretty much be assured of uniform distribution of your developing agents in your matrix.

Kirk

PS - glad to see you back here!

Kirk Keyes said:

Won't you just run into the old issue of particle separation due to bulk density?

Click to expand...

That’s more likely if sulfite and borax are mixed together with developing agents, so I expect less problem with my strategy. But it remains to be tested.

How's this idea - find a matrix that is soluble in both solvent and water and then dissolve your phenidone and ascorbic into it with the solvent. Pour the solution out into a tray and let the solvent evaporate. Then grind the matrix to a fairly uniform particle size so that it quickly dissolves in water. Then you can pretty much be assured of uniform distribution of your developing agents in your matrix.

Click to expand...

That’s too much work
It’s more work than weighing individual ingredients each time I develop.

If this were a $500k/yr business, I’d probably use a tablet press to punch out tablets. But I’m looking for a good small scale processing solution...

This lot does my head in - If you only process BW in small batches get some Rodinal, not the magic brew some claim, but it does work - Leave your head clear for making images

Ryuji


too bad it has to be mixed / suspended into a liquid
i have often wished there could be just a powder to submerge
my film into, no liquids ... and
after " x minutes " it would be ready to fix ...
when i read the title of your thread, i thought my wish had come true !

happy holidays !
john

jbaphoto said:

This lot does my head in - If you only process BW in small batches get some Rodinal, not the magic brew some claim, but it does work - Leave your head clear for making images

Click to expand...

hi jbaphoto:

you might not realize .. but Ryuji is an inventor of developers
and maker of emulsions ... i haven't used his magic brews
but from all reports they work well, very well !

john

jnanian said:

too bad it has to be mixed / suspended into a liquid
i have often wished there could be just a powder to submerge
my film into, no liquids ... and
after " x minutes " it would be ready to fix ...
when i read the title of your thread, i thought my wish had come true !

Click to expand...

Ha! I don't know how to do that but that's not a bad idea... It'd be hard to pour powder to your tank though.

Ryuji said:

It'd be hard to pour powder to your tank though.

Click to expand...

That's where your Jobo rotary processor comes in handy!

I actually never owned a Jobo. It'd be a good idea but it's still expensive...

This sounds quite interesting, I wish you complete success with it.

Experimenting with developers is nothing but fun in my opinion-

What could be harder than measuring out 100ml of T-max developer in a small graduate each time you need it. The stock solution seems to keep for a long, long time. Its high viscosity makes it very easy to pour to the exact measure, even when pouring from the gallon jug. If I were to 'home brew' a developer, I'd copy that.

Moved from another thread.

My question is: How can we guarantee that the powder stays mixed well? I guess the user could shake the jar before measuring-out some powder, but I'm still not sure that coarse and fine powders would be mixed uniformly.

Click to expand...

See above.

Also, acid touching alkali (as powders) can cause problems

Click to expand...

Depends on what kind. If it is borax and ascorbic acid, there is no problem.

XTOL fixed the problem by having two packets.

Click to expand...

I think the packaging of XTOL was decided so as to minimize the impact of small errors in metering process as well as potential risk of ingredients segregation.

One thing I can tell you is that it is a LOT easier to get better uniform mixture in a small mixer (say a kilogram or less of the powder developer) than a large mixer producing 100kg or a metric ton.

The trickiest part is to mix phenidone (very fine sticky powder used in such a small quantity) uniformly first. Then the rest of the problem is a lot easier. The best way to mix is to use a slow random motion to mix in a vessel with lots of free room. This is exactly what industrial mixers can’t do.

Ryuji said:

The trickiest part is to mix phenidone (very fine sticky powder used in such a small quantity) uniformly first.

Click to expand...

I tried mixing 1 part phenidone with 9 parts ascorbic acid, in a small jar. Both are fine powders, and they mix together well. This gives me a 10% powder-mixture of phenidone that's easier to weigh. For example, I weigh out 1 g of this mixture to get 0.1 g of phenidone. Just to be sure, I shake before each use. Repeatability appears to be fine with this powder-mixture.

I like your powder-idea, and I suspect that you can make it work, if my test above is any example. Be sure to have somebody test it in humid Florida and dry Arizona. For me, shaking two jars for a few seconds before measuring out powders is no problem. BTW, do you of ways to make phenidone/dimezone dissolve faster?

Mark Overton

albada said:

BTW, do you of ways to make phenidone/dimezone dissolve faster?

Click to expand...

Don't tell me this is different from what you learned from old books, but I do know of a good way. Dissolve all alkali in water first. Then add just a bit of sulfite and a bit of ascorbate. Dissolve any organic compound (Phenidone, Dimezone, benzotriazole) and then add the rest of the ingredients. That is, those organics will dissolve easily in alkaline solution of a low salt concentration.

Kirk Keyes said:

Won't you just run into the old issue of particle separation due to bulk density?

Click to expand...

I remember some postings awhile ago on another thread about measuring from mixtures. But I can't find the postings even with Advanced Search. Anyway, I think Ron Mowrey (PE) posted some cautions based on his experiences at Kodak. Hopefully he'll chime-in on this.

But I remember reading web pages about it, and seeing diagrams of different ways that particles of differing weights and sizes can sort themselves in a container. Perhaps you'll be okay if your chemicals have similar densities, because neither will try to float above or sink below the other. I just wish I could give you a link to that thread...

Mark Overton

Ryuji said:

Ha! I don't know how to do that but that's not a bad idea... It'd be hard to pour powder to your tank though.

Click to expand...

naaah
i am sure i could dump a whole bunch of powder into a tank,
or i could easily put it in with the lights out like when i fill it with film
i know i could easily fill a tray with it too ...
and i just remembered when i was in france a few years ago
i bought a few kitty litter trays to hand process sheets in --
powdered developer would have been the perfect choice instead
of the rot gut coffee developer i used

albada said:

Anyway, I think Ron Mowrey (PE) posted some cautions based on his experiences at Kodak. Hopefully he'll chime-in on this.

Click to expand...

Because of the political behavior started by some, there is an agreement that he shall not post on my thread and vice versa. We are not supposed to mention each other’s work.

But I remember reading web pages about it, and seeing diagrams of different ways that particles of differing weights and sizes can sort themselves in a container.

Click to expand...

That sounds right. But the way ingredients segregate depends a lot on the construction of the mixer and revolution speed. Although this is not a high tech or anything, there is more industrial know-how in this area now than just a couple of decades ago.

Perhaps you'll be okay if your chemicals have similar densities, because neither will try to float above or sink below the other.

Click to expand...

The key is that you stir the vessel slowly and randomly each time you take the portion you want.

I also thought about making a paste. Like toothpaste. You decide like take 10cm per liter of water to make working developer. This is doable but too much work to package the stuff!

Hey Ryuji!
Due to globalization I think we have a couple of disused toothpaste packing machine setups sitting here.............!

And I think you just stole "the other guys" thunder, I'm about to wrap up the festive seasons playtime with tea, ascorbate and soda, and will be hunting high and low for Vitamine B to play with! Thanx!

Ryuji,
Your powder mix may be similar to the powder Fomadon Excel:
http://www.freestylephoto.biz/pdf/msds/foma/Fomadon_Excel_W27_Film_Dev.pdf
I have a number of 1L packs of this years past the expiry date that still work OK.
It is not known how Foma mix the powder but if you could match their mixing your powder should keep well.
If not you could add a little metabisulfite to reduce the pH and oxidation rate of any damp ascorbate.

Alan Johnson said:

It is not known how Foma mix the powder but if you could match their mixing your powder should keep well.
If not you could add a little metabisulfite to reduce the pH and oxidation rate of any damp ascorbate.

Click to expand...

I think it’s more important to keep the powder in environment free of excess moisture. I’d use vacuum container anyway.

I’d rather not use metabisulfite in this. Zat stuff stinks. As I said before, I’d rather use a water soluble polymer and sorbitol to “dilute” Phenidone and then make the fine powder stick to other ingredients used in more bulk quantities.

Yeah if I were to sell the products I’d rather make fancy tablets or paste in tube. But at this point and time it is commercially inviable. Unless... someone wants to start a kickstarter project and raise some money for the project haha.

But then I thought about it. The developer stabilizer I’m going to use is not a compound that’s commonly available. When Silvergrain products were sold, I actually prepared that stuff in my lab and shipped it to the factory. So publishing the formula is also of little value... unless I somehow make this stabilizer available.

Ryuji said:

I also thought about making a paste. Like toothpaste. You decide like take 10cm per liter of water to make working developer.

Click to expand...

I like the idea of a paste. Have you considered packaging it in a wide shallow jar like a facial cream? The user would measure level spoonfuls of it. The jar could come with two or three sizes of cheap plastic spoons. But then some cream would be on the bottoms of the spoons, adding too much concentrate. Hmm, there must be some way to use a paste...

Mark Overton

I look forward to hearing about the results.

What I vaguely recall, from mixing my own monobath developers, is that there is some magic to the order in which things are brought into solution. I.e. one doesn't add all the phenidone at once. But I'm sure you'll work it out.

Some time ago I was thinking that some monobath paste / goop woudl be really handy. Seems like it wouldn't be too hard to make a version of the type 55 stuff and a spreader that'd be good for very rapid development in the field.

Got a couple of tests done.

Standard usage: take one tablespoon (15ml) of the mixed powder from the jar while stirring and dissolve in 870milliliter of water to make working solution. That is 20g/L. (The actual density of the powder mix is 1.18, so one tablespoon will be 17.4g assuming tablespoon is exactly half fluid ounce by volume.) If you are developing one 35mm film, that's one teaspoon of powder in 290ml of water. You can minimize the wastage by using a cheap digital balance. If you are doing push processing, 30g/L works better. If you are developing Acros or TMX, 15g/L gives more reasonable development time. The powder dissolved while I was loading the film.

The powder mix is slightly yellowish. This is because of the developer stabilizing agent. Dimezone S is the orange granules. Several portions I took from the jar had exact same pH, plus/minus 0.05. Metering by measuring spoons has been pretty consistent, as well.

Attached are the closeup of the powder mix (closeup, intentionally decreased exposure and boosted contrast to show the texture), another with Macbeth chart for color and reflectance reference. I just took the powder from the jar like usual, it did not come straight out of a mixer, but looks just like that. Then two sample images, exposed on Plus-X from 1990s exposed at EI 125 and developed in this soup, 5g in 250ml water, developed in stainless tank for 5.5 min at 22C. The film was exposed with a Russian toy camera, with a fixed focus lens, so the image isn't really Mamiya-sharp. But you get the tonality and feel. The developed negative scanned very well - fine grain, moderate accutance boost, lots of shadow details, and good highlight contrast.

Umm, so, Can I Test It?

Maybe I'll give out a limited number of samples, but for that, I'll have to think about how to package and ship...