D76 One Shot

[pentaxuser]

What Donald said.
A powder mixture that starts out homogenous doesn't stay that way. It has to be remixed to make it homogenous again. And re-mixing needs to be done with stirring - lots of it, and with a quite specialized technique - and not shaking, because shaking tends to separate out things, not mix them evenly.

So is this a specialised technique that cannot be achieved by a person stirring at home because he (a) cannot achieve the level of mixing needed or (b) would have to spend more time stirring than is feasible such as say 30 mins

If it were (b) then I understand the logic in this in that few if any people might be prepared to devote such a period on each occasion they needed another shot for one film but if its the lengthy period of stirring that is the problem then how long is this period

If it is (a) what do you know about the specialised stirring technique that enables you to be sure it cannot be achieved by a person stirring at home and can you tell us specifically what this specialise stirring involves


Thanks

pentaxuser

 

[RalphLambrecht]

Matt I have no idea who makes this stuff these days and really this doesn't matter as long as you can be sure that it is "mixed" exactly as you describe. If so my thinking, possibly flawed, is that we can be sure that the exact amount of the correct ingredients are delivered into each packet. Thus any other method such as scooping out only part of the pack does rely on luck to an extent to get the absolutely right portions onto only part of the pack

So I go back to my original thought that a thorough shake is the best way to ensure that the tablespoon gathers as near as make no difference the correct ingredients in the correct portions

However it seems to me that while a good shake should mix it correctly there is a chance it may not and we are back to the question of whether the tablespoon might miss enough of the least amount of ingredients, metol and borax to affect the negatives to the extent that they will be sufficiently different for negative developed in the exact amount of each ingredient

Kodak may have done tests on this in case users asked the obvious question about using only part of the packet but does anyone know if it did and if it published the results

I am trying to establish what facts we have that will result in an answer that might help those who are wondering about trying this method to know the facts

I have no vested interest in what the answer might be other than it helps users to decide whether this method will work and to what extent it might work

pentaxuser

I'm going to try the salt next Thursday and will report on the results.

 

[MattKing]

So is this a specialised technique that cannot be achieved by a person stirring at home because he (a) cannot achieve the level of mixing needed or (b) would have to spend more time stirring than is feasible such as say 30 mins

If it were (b) then I understand the logic in this in that few if any people might be prepared to devote such a period on each occasion they needed another shot for one film but if its the lengthy period of stirring that is the problem then how long is this period

If it is (a) what do you know about the specialised stirring technique that enables you to be sure it cannot be achieved by a person stirring at home and can you tell us specifically what this specialise stirring involves


Thanks

pentaxuser

The equipment used commercially or for lab use for stirring is really quite expensive. And the things that make it expensive are the things that make it consistent and repeatable.
Most importantly, the results are monitored and verified by regular sampling and careful chemical testing - not just buy using some of the powder to develop the film and looking at a few negatives.
You can't tell whether or not the mix is right by looking at it! And you can't tell whether the mixture is right by examining a few negatives - particularly considering that any error at the beginning of the process may have a tendency to have a compounded cumulative effect at the end.
I have no problem with people experimenting with this, or assuming a fair amount of risk in trying this for themselves.
I'm concerned with people recommending to others that it is easy to get consistent and repeatable and reliable results, when someone's success might be related to how they are doing the stirring, including, for each mixing step, the technique employed, vessel used, implement used, humidity and other environmental conditions in effect at the time of the mixing, and probably some other variables that don't occur to me at the moment.

 

[Don_ih]

Powder mixers have been in use for a long time. They are basically like the mixer on a cement truck - cylinders with screw-lifters that shift the powder. Now, the way you use it is you put the powders in and turn it on for the correct amount of time and - voila - powders mixed. These machines aren't cheap because they are guaranteed to work. But you could easily make one using a drill and gallon bucket and strip of plastic to glue inside the bucket as a screw lift. Then you could be Betty Krocker. Or you could be Kodac.

I have no problem with people experimenting with this, or assuming a fair amount of risk in trying this for themselves

The risk involved in trying something like this for yourself is getting a result you don't like. It's not likely you'll lose an eye or anything - so I don't see there being a "fair amount" of risk. The hyperbolic nature of the arguments against just trying this are, truthfully, a drag. Just a complete downer. Completely anti-fun, anti-experimentation, anti-learning.

Here's an experiment. Try to make a tablespoon of D76 not develop a roll of film. Shake the powder. Place it on a hive filled with angry bees or a large coffee can filled with running vibrators. Give it the ol' shimmy and shake. Take it jogging. See if there is any way possible to actually get that powder to separate noticeably. You know. Just for the hell of it.

 

[Arvee]

The hyperbolic nature of the arguments against just trying this are, truthfully, a drag. Just a complete downer. Completely anti-fun, anti-experimentation, anti-learning.

I agree. I left the discussion for just this reason.

 

[Donald Qualls]

Try to make a tablespoon of D76 not develop a roll of film.

Isn't it easier to just follow directions? Stock solution isn't hard to store, and keeps for several months (officially six, isn't it?) -- I have personally mixed Dektol in half the water, which made the stock solution keep for literally years. I'm not sure everything would go into solution with D-76 in half the water, it has more than twice as much sulfite -- but that makes the stock solution stronger in sulfite than D-72/Dektol at double strength, so there's no sensible reason the stock solution wouldn't keep for a year or more in a truly airtight container with little or no airspace. To me, the only practical reason to want to mix a partial batch is if I don't have room to store the stock solution -- in which case I'd probably be using Df96 anyway, since it's one bottle for developer and fixer.

 

[Don_ih]

Isn't it easier to just follow directions?

Isn't it more fun not to?

 

[Donald Qualls]

Isn't it more fun not to?

Depends on what you consider fun. I'm not much of a gambler. My photos in general aren't great art, but they're important to me, and following directions seems like a better way to give my negatives the best chance than experimenting with images that I consider important.

I do experiment (else I'd have never tried HC-110 as a monobath, double strength Dektol stock, various levels of KBr in my Parodinal, phenidone as a 2% stock solution in 91% isopropyl vs. mixing H&W Control immediately before use, low contrast Caffenol, etc.), but I try to do so on test rolls, exposed specifically for the test. For images I care about, I either follow directions or use the results of successful experiments, proven by prior tests.

 

[Don_ih]

use the results of successful experiments, proven by prior tests

And what is happening here? What was the very first post in this thread if not a successful experiment, which he then repeated later on?

 

[Arvee]

Facts to add to the mix:

I have terrible allergies and need to use a sinus rinse regularly. The rinse is made with 250ml H2O and a powder mix of NaCl and NaHCO3 in a 3:1 proportion. The NaCl grains are about 5x to 8x larger than NaHCO3 grains in size. I combine 3 Tbs to 1 Tbs in a plastic cup and spoon .25 tsp into the 250 ml of water.

This morning I shook the cup to mix and I then spooned out .25 tsp onto a piece of paper and examined it under my microscope at 30x.
I found a very uniform distribution despite the disparity in grain size of the two different chemicals.

I then put a previously mixed/stirred sample of dry 76 under the 'scope. The M appeared as a very fine grain, the SS appeared similar to NaCl in size, the Q appeared as 6:1 crystal bar with a dia. about the same as a grain of salt, and the B was about 5x larger than the SS in dia.

I spread the mix out to about a 1.5" circle and scoped the entire sample. Again, very uniform distribution of grain sizes/shapes across the sample of four chemicals in the mix.

I am convinced using this method to mix small batches of 76 using spoon measurements in small quantities of water makes a proper strength solution of 76 avoiding the annoying pH rise that takes place after mixing. I seem to recall PE saying that this pH rise reaction took place over the first 24H and he began to use it safely after that period of time.

I have completed my third film strip test from the first batch of dry 76 and the negs are virtually identical to the first two after comparing all three on the light table. I have consumed about half of the dry mix.

Again, my $ .02 contribution to the discussion....not speculation or 'what I've read or heard.'

 

[pentaxuser]

The equipment used commercially or for lab use for stirring is really quite expensive. And the things that make it expensive are the things that make it consistent and repeatable.

I'm concerned with people recommending to others that it is easy to get consistent and repeatable and reliable results, when someone's success might be related to how they are doing the stirring, including, for each mixing step, the technique employed, vessel used, implement used, humidity and other environmental conditions in effect at the time of the mixing, and probably some other variables that don't occur to me at the moment.

So two things Matt. What is it about the lab equipment that makes it consistent and repeatable that cannot be achieved by the human hand or the kind of small mechanical stirrers that you can buy for baking. My wife has one of these and it has 3 settings of slow, medium and fast. I have no idea which speed replicates the one needed for commercial D76 stirring but perhaps if you know exactly how these commercial stirrers work you can say what speed it stirs at and specifically what it actual does that cannot be replicated by hand or small mechanical stirrer

Doesn't your second point really sum up the stance taken by all who are simply puzzled as to why any deviation is worthwhile i.e. why take any risk no matter how small if it isn't necessary?

What I have been trying to ascertain from the start is what is the probability of failure of the one shot method and what is the likely frequency of failure and where in the spectrum of failure (total to only a little less than perfect) does the one shot come

So far no-one who has tried it has reported anything other than what appears to be consistent success. Well you may say that advocates of the one shot method are unlikely to report failure. However call me naive if you like but I have enough faith in those using the "one shot" method not to say it has always been successful if this has not been the case and certainly to say if some attempts have resulted in films being consigned to the waste bin

I am all for telling people of the probability of the risks and what they might do to minimise those but if actual data or specific information is not available then that needs to be said as well

pentaxuser

 

[pentaxuser]

Arvee, can I ask if the D76 to which you refer is the home-made version or the commercial D76 It would appear although not actually stated that the home-made version does not contain the "secret sauce" ingredients. These appear to be the ones that enables Kodak to put D76 in one packet but a lack of these forces Ilford to put it into two packets

Exactly how these might affect the viability of using one shot is unclear to me in that one theory holds it is more the effect of air that sets in motion an inevitable adverse reaction whereas currently the discussion has concentrated on the inconsistency of mixing in the one shot method

Thanks

pentaxuser

 

[MattKing]

Here's an experiment. Try to make a tablespoon of D76 not develop a roll of film. Shake the powder. Place it on a hive filled with angry bees or a large coffee can filled with running vibrators. Give it the ol' shimmy and shake. Take it jogging. See if there is any way possible to actually get that powder to separate noticeably. You know. Just for the hell of it.

If you could tell whether or not the D-76 was homogenous by looking at it, then there would be no problem with doing this.
The problem is, most of us (those who don't have a chemistry lab or sensitometry equipment at hand) can't tell if the mixing was homogenous until we are well into spending $240.00 worth of film - 16 rolls at $15.00 each.
That is the risk - substandard film results, and partially or completely wasted photographic time.
Here is a question for you - if the results obtained by doing this meant that rolls ranged such that one would need to be printed on grade 1 paper while 14 rolls later when a roll would need to be printed on grade 3 paper (assuming the same scene and lighting exposed on each roll) would you consider the experiment a success?

 

[Don_ih]

If you could tell whether or not the D-76 was homogenous by looking at it, then there would be no problem with doing this.

It wasn't my challenge to be able to see anything.

Here's my new challenge: Try to make 1 tablespoon of D76 not develop a roll of film properly. Put your D76 powder on your washing machine and take it on plane rides. See if you can shake it enough to cause it to not develop film properly.

Spread it out on a cookie sheet. Put it on a big speaker while The Ride of The Valkyries plays in endless loop at 160 db for three days. Then carefully skim a tablespoon of the powder that's just sitting on top.

As for print grades - some people prefer negatives that print to grade 3. And it would be pretty odd to get a negative that needs to print to grade 1 unless you overdeveloped, doing this. Maybe you should try it?

I can't try it, because I don't do it, anymore.