New film developer idea (all powder!)

[Christiaan Phleger]

Please count me in as first in line . PM me when you're ready I eagerly await.

 

[Ryuji]

A 35mm film canister holds about 30ml or 35g of this powder mix. One half of a film canister full of this stuff dissolved in 1 quart of water makes standard developer working solution.

 

[albada]

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

In my previous job, our products were subjected to "four corners testing": low/high temperature and low/high humidity. For a developer, the worst corner is probably hot-and-humid, and the south-east USA provides plenty of both.

So it would be interesting to test this in an area like Florida. A good test would be to have the tester keep the jar in the garage (no A/C), and open/close the jar once a week. If the powder keeps much of its activity after a year of that, it's solid!

Mark Overton

 

[Kirk Keyes]

What's under the pH meter - a battery charger for it?

(Sorry, you know my interest in lab gear!)

 

[Ryuji]

Kirk,

That meter can measure pH, oxidation/reduction potential and temperature. The meter runs on the built-in rechargeable battery, and is waterproof.

The base unit is an induction based charger that sends the electric power to the handset without any exposed contact.

It's not so much of an issue now, but when I had a much bigger lab space, I had an emulsion making station at one corner, processing station at another corner, and chemical preparation station (which also doubles as analytical bench) with its own sink in the middle. I had two pH meter setups back then, but a unit like this made my life a lot easier.

This pH meter can recognize buffer automatically, and it also recognizes and calibrates at 9.18 if user chooses to do so. This is particularly useful for critical film developer work.

BTW the values shown are the electrode hodling water and not the actual developer pH.

 

[analog what is that?]

In my previous job, our products were subjected to "four corners testing": low/high temperature and low/high humidity. For a developer, the worst corner is probably hot-and-humid, and the south-east USA provides plenty of both.

So it would be interesting to test this in an area like Florida. A good test would be to have the tester keep the jar in the garage (no A/C), and open/close the jar once a week. If the powder keeps much of its activity after a year of that, it's solid!

Mark Overton

I live in Norway, frigid coast of the North Sea/ Norwegian sea.
Send a few cannisters here, and I'll do a long term low temperature / high humidity test, the north sea supplies humidity in abundance, the norwegian hountains flushes cold air right down into our valleys, we can have -25 centigrade and humidity in the +95% here today we have +1.3 Centigrade and humidity 110% (it is raining icecold water).

I'll put ne cannister in my cold cellar, one in my shed where I keep my lawn mower (outside temp and humidity) and one in my attic for instance and report back after a dely of your choosing.......

 

[Keith Tapscott.]

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?

Geoffrey Crawley designed a two part Phenidone + ascorbic acid developer which may provide you with ideas.
http://web.me.com/johnfinch/PictorialPlanet/advanced_photography/fx-55.html

 

[Ryuji]

Keith, thanks for the link. One problem with the formula FX-55 is that it does not have any precautionary measure to prevent sudden death of XTOL problem. I'm reluctant to use any ascorbate based developer formula that doesn't have a reasonable mechanism to cope with this problem.

Also, I since abandoned two-powder stock idea. It's not worth the trouble. It's much better to have a single powder mix. Slight metering error in preparing working solution is equivalent to slight error in dilution. With most films, this is not going to be a problem. With two powder stock approach, each part would have to me mixed very thoroughly and weighed very carefully, or the developer activity won't be consistent enough for practical purposes.

Film developer is always used in 18-27C temperature range, and anything else is a storage condition issue. It is just that those who live in hot and humid area without climate control in darkroom should use a bit of precaution, like double container with desiccant in the first layer. This is still a lot more eco-friendly than dealing with organic solvent that does not add useful functions to the developer, or risking a lot of wastage by preparing stock solution of limited shelf life.

When Silvergrain chemicals were offered commercially, one of my proposals (always rejected for business reasons) was to offer all powder line specifically designed like this, to avoid shelf life issue, and to minimize the fuel burnt to carry water. By purchasing liquid concentrate chemicals, you are financing extra fuel burnt to carry water from the factory to distributor warehouse as a part of the product price, and then pay shipping for the weight of the water in the product. Would you justify shipping pounds of water when a tablespoon of powder will dissolve in minutes in your water?

In my view, rapid fixer and wetting agent cannot be provided as powder stock, but developers, stop bath and washing aid can be packaged as all powder stock with similarly convenient "tablespoon per quart" type usage.

 

[Ryuji]

Hey y'all,

I'd appreciate if you can help this.

(there was a url link here which no longer exists)

I didn't tell the whole story but I'm trying to figure out the best way to ship a small amount of samples.

 

[Kirk Keyes]

The base unit is an induction based charger that sends the electric power to the handset without any exposed contact.

That's SWEET!

 

[Ryuji]

Yeah, it is originally made for field use like environmental monitoring, but photographic chemicals are just as harsh you know. Before I spent the money to get the real deal I bought a few of $100 testers that were never reliable... unstable reading, even with well cleaned double junction electrodes. (ALWAYS clean the electrode at the very last thing in the shift and never at the beginning or during... common sense!)

 

[Ryuji]

Oh btw that meter takes AAA NiMH batteries, and it trickle charges. So I usually keep the meter off the charger... but I can just replace the cell without shipping it back for service. Not bad at all.

 

[Ryuji]

More test done.

Studio shot: Fujifilm Acros EI 100, 15g/L powder mix, developed 9 minutes at 20C.
Available light shot: Ilford Delta 3200 EI 1600, 20g/L powder mix, developed 10 minutes at 20C.

Both shot with new Mamiya 6. Studio shot is 150mm, window shot is 50mm.

For comparison purpose, I included a color digital shot (ISO 1600, TS-E24mm f/3.5 II). Both shot at f/4 1/30s. I didn't burn in the window in either version... Delta 3200 is offers rather narrow dynamic range as far as film is concerned, but still it offers a lot more than full frame digital.

 

[Ryuji]

Works well with HP5 Plus (8 min) and Delta 400 (8m30s) both at 20g/L and 20C.

Sample photo by Tim Beaulieu of MIT. I think he shot with Hasselblad 500c with 80mm.

 

[analog what is that?]

Well whats the current state of the formula, or is it a secret?

And which of the two last mentioned films was that?

 

[Ryuji]

Club Passim signage photo was on HP5 Plus.

I didn't scan Delta 400.

I'm not a fan of posting daily or hourly formula like today's special soup recipe.
We don't need many formula that produce the same result by different ways.