D76 One Shot

[pentaxuser]

No, I'm saying that the steps necessary to ensure even mixing are not simple, and that the quality of the mixing - the homogeneity of the results - will differ because the particles in the bag will be of different size and shape and mixability then the home mixed stuff.

So home mixed D76 is OK for stirring and using one shot and is this because of all the particles of the known ingredients are of a homogeneous size? If so what is it specifically about the "secret sauce" D76 that makes stirring it a "lottery" If it is secret how do we know that the "secret ingredient(s) are of the kind that are sufficiently different in size and density that ensure that despite a lot of stirring before it is spooned out, mixing in the right quantities is near impossible?

Thanks

pentaxuser

 

[Donald Qualls]

how do we know that the "secret ingredient(s) are of the kind that are sufficiently different in size and density

Correct question is "how do we know they're homogeneous with the other four to a dozen types of particles in the mix?" And the answer is, there's no reason they'd need to be.

 

[MattKing]

No - home mixed probably leads to inconsistency more often than not, but may sometimes be okay.
And results from the home mixed experience are unlikely to reveal much about the experience with the commercial mixture, because the contents of the package are so different - they will not respond the same way to the same attempts to mix them.

 

[MattKing]

Correct question is "how do we know they're homogeneous with the other four to a dozen types of particles in the mix?" And the answer is, there's no reason they'd need to be.

And part of the "secret sauce" is almost certainly how they are bound to each other - the ingredients in the package aren't just loose bits of the individual components, but instead they are compounds designed to help protect the individual components from interacting.

 

[MattKing]

If D-76 could be made homogenous, they would sell it like that, and advertise that it can reliably used one "dose" at a time.

 

[Don_ih]

If D-76 could be made homogenous, they would sell it like that, and advertise that it can reliably used one "dose" at a time.

Why would they? Apart from them not expecting anyone would do it, they would then have to guarantee that the powder would stay fine after being opened - which they don't and won't do. Humid air will have a fairly quick impact on exposed D76 powder. It's not Tang (which was a homogeneous powder, incidentally).

Incidentally, they used to sell Dektol in little envelopes that held a tablespoon of powder - enough for a tray to make a dozen prints or so. I have a box of them (haven't tried any). Must've been quite interesting filling those 1.5" square envelopes with their candelabra....

 

[relistan]

And part of the "secret sauce" is almost certainly how they are bound to each other - the ingredients in the package aren't just loose bits of the individual components, but instead they are compounds designed to help protect the individual components from interacting.

For example, in L.F.A. Mason's book (former head of research lab at Ilford), he talks about the need to coat the alkali with an extremely fine layer of various acids in order to keep them from interacting with the developing agents or the chelating agents. I imagine that this also applies to the sulfite. He goes into ways in which this was accomplished, none of which are simple.

You can easily imagine that in the presence of moist air, that microscopic layer of acid salt would break down. After reading his explanation I am now of the opinion that protecting the contents of the opened bag from moisture is at least as important as getting the mix right. I suspect that environmental conditions are a ticking clock on how long until it doesn't work properly.

Notably he says in the book that keeping the developing agents in their own bag (with a bit of metabisulfite) away from the alkali is the safest and simplest thing. Which is what Ilford still does, 50+ years later.

 

[Donald Qualls]

used to sell Dektol in little envelopes that held a tablespoon of powder - enough for a tray to make a dozen prints or so.

The first time I developed film without supervision (at age 10, 1970) was with one of those packets -- it was labeled "MQ Universal Developer" (but with a Kodak logo, not Ilford, which I'd never heard of at that early date), but the dilutions were the same as for Dektol (1+1 or 1+2 for prints, 1+3 for plates -- because they were still a thing when those packets were printed, probably around 1960) and 1+9 for film. At that time I had packets of dry stop bath (citric acid?) and dry fixer.

I have a small box of those MQ packets in my darkroom, expired in the 1970s, that came with a box of mixed darkroom supplies (that I bought for the 620 spools I could see in the eBay photo) almost twenty years ago.

For those, on a line probably set up around 1950, I'd bet they did in fact bulk mix the metol, hydroquinone, sulfite, KBr, and carbonate (may not have even bothered with sequestrants or chelating agents, since it was intended to be mixed and used immediately, one-shot) and fill the packets with the premixed powder.

 

[pentaxuser]

Correct question is "how do we know they're homogeneous with the other four to a dozen types of particles in the mix?" And the answer is, there's no reason they'd need to be.

Donald, I am unsure what the answer is telling me. I have an idea what it means but I may be wrong so can you spell it out to me as simply as possible?

Thanks

pentaxuser

 

[pentaxuser]

No - home mixed probably leads to inconsistency more often than not, but may sometimes be okay.
And results from the home mixed experience are unlikely to reveal much about the experience with the commercial mixture, because the contents of the package are so different - they will not respond the same way to the same attempts to mix them.

Why? Matt. I am trying to understand what is is about what you know about the secret ingredients that causes you to be so sure

Thanks

pentaxuser

 

[pentaxuser]

For example, in L.F.A. Mason's book (former head of research lab at Ilford), he talks about the need to coat the alkali with an extremely fine layer of various acids in order to keep them from interacting with the developing agents or the chelating agents. I imagine that this also applies to the sulfite. He goes into ways in which this was accomplished, none of which are simple.

You can easily imagine that in the presence of moist air, that microscopic layer of acid salt would break down. After reading his explanation I am now of the opinion that protecting the contents of the opened bag from moisture is at least as important as getting the mix right. I suspect that environmental conditions are a ticking clock on how long until it doesn't work properly.

Notably he says in the book that keeping the developing agents in their own bag (with a bit of metabisulfite) away from the alkali is the safest and simplest thing. Which is what Ilford still does, 50+ years later.

relistan, how does this translate into using D76 one shot and what if any implications might this have for attempting to use the 2 bag ID11 as one shot?

Thanks

pentaxuser

 

[Donald Qualls]

Donald, I am unsure what the answer is telling me. I have an idea what it means but I may be wrong so can you spell it out to me as simply as possible?

Thanks

pentaxuser

What I mean is that there's no sensible reason (other than to support partial-bag mixing) for the particles in packaged D-76 (sodium sulfite and borax crystals, metol and hydroquinone flakes, "secret sauce" that may or may not be coated onto one or another of those, sequestrants and chelating agents) to be all the same size, and they can't reasonably be all the same density (sulfite is denser than metol, unavoidably, for instance). Therefore, there's nothing but lack of space in the bag to prevent the powders, presumably mixed fairly well when the bag was filled, from separating to some degree in handling and shipping.

If the chemicals aren't combined in a way that each particle contains everything in the mixture (unlikely, but not impossible; some level of this might be the "secret sauce" that lets the metol and sulfite be added together to the water), there's no reason to believe they're going to be immune to separation via particle density and size, just like gravel in a frost sorted pothole.

 

[Don_ih]

relistan, how does this translate into using D76 one shot and what if any implications might this have for attempting to use the 2 bag ID11 as one shot?

Thanks

pentaxuser

Essentially, using D76 one-shot increases the amount of time the open package of dry powder is exposed to air (whatever humidity it may be). So, the more time passes, the more it will degrade - probably. ID11 could very well be packaged by a line of Oompa Loompas with teaspoons, so each of the two packages may be not very well mixed.

(I should add i find it pretty much impossible to believe any manufacturer of any significant size would add individual powders to the packages. I can only believe they would mix a large amount (in a cement-mixer type mixer) and put that in packages. )

 

[Donald Qualls]

i find it pretty much impossible to believe any manufacturer of any significant size would add individual powders to the packages.

This is a question of economics. Some products, like biscuit mix, must be pre-incorporated (if the fat doesn't coat the flour particles, you won't get good biscuits). And some are expected to be used in partial package quantities, like the sea salt my partner orders by the 40 lb. bucket for the reef aquarium -- but that can readily be produced so all the grains in the bucket have the same composition (spray drying from solution will do it). On the other hand, if there's no need for the contents of the envelope to be homogeneous enough to use a partial bag and get the same results as mixing it all and dividing the resulting solution, which way it's done is a matter of cost.

 

[relistan]

relistan, how does this translate into using D76 one shot and what if any implications might this have for attempting to use the 2 bag ID11 as one shot?

It means that an open bag used this way, even if mixed perfectly so that you get the right amount of ingredients, will begin the process of breaking down the coating on the powder and you have an unknown amount of time to get it all used.

This will be heavily dependent on your atmospheric conditions and how well it is resealed. I would suggest that if you are doing this, you should seal it back in the pack or into a jar—under a layer of butane in both cases.

 

[MattKing]

Why? Matt. I am trying to understand what is is about what you know about the secret ingredients that causes you to be so sure

Thanks

pentaxuser

What I mean is that there's no sensible reason (other than to support partial-bag mixing) for the particles in packaged D-76 (sodium sulfite and borax crystals, metol and hydroquinone flakes, "secret sauce" that may or may not be coated onto one or another of those, sequestrants and chelating agents) to be all the same size, and they can't reasonably be all the same density (sulfite is denser than metol, unavoidably, for instance). Therefore, there's nothing but lack of space in the bag to prevent the powders, presumably mixed fairly well when the bag was filled, from separating to some degree in handling and shipping.

If the chemicals aren't combined in a way that each particle contains everything in the mixture (unlikely, but not impossible; some level of this might be the "secret sauce" that lets the metol and sulfite be added together to the water), there's no reason to believe they're going to be immune to separation via particle density and size, just like gravel in a frost sorted pothole.

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.

Incidentally, they used to sell Dektol in little envelopes that held a tablespoon of powder - enough for a tray to make a dozen prints or so. I have a box of them (haven't tried any). Must've been quite interesting filling those 1.5" square envelopes with their candelabra....

D-72/Dektol may very well be easier to divide by weight than other chemicals. And those packages may very well have been less consistent than the larger packages, mixed up whole with water. But there are a number of ways to divide an amount of powder into smaller segments that don't involve pouring the substance into bags.

 

[MattKing]

FWIW, if you look up how to do this in the baking world, one of the recommendations is to add something like cocoa or brown sugar into what is otherwise white powder so one can actually see how homogenous your mixture is, and whether more stirring is still required.

 

[relistan]

FWIW, if you look up how to do this in the baking world, one of the recommendations is to add something like cocoa or brown sugar into what is otherwise white powder so one can actually see how homogenous your mixture is, and whether more stirring is still required.

D-76 + cocoa is the new developer

 

[Anon Ymous]

D-76 + cocoa is the new developer

A staining one!

 

[Don_ih]

D-76 + cocoa is the new developer

I hear they've tried it, recently - but it was tar-coloured Dektol.

 

[Don_ih]

A powder mixture that starts out homogenous doesn't stay that way.

It takes a lot of energy to separate a contained homogeneous powder. Mix some sand and flour in a glass jar and put it in the trunk of your car. My bet is, after 5 years of driving, it'll look the same.

 

[MattKing]

It takes a lot of energy to separate a contained homogeneous powder. Mix some sand and flour in a glass jar and put it in the trunk of your car. My bet is, after 5 years of driving, it'll look the same.

If it was two similar versions of similarly dense sand - the "metol" sand and the "sulfite" sand, as it were - and it was in a flexible bag that was moved around from time to time, the results would probably be different.
And if there is 50 times as much "sulfite" sand as there is "metol" sand, and the "metol" sand is quite important to your use of the sand, assuring even enough distribution of the "metol" sand might be a challenge.

 

[gone]

My last roll of film, so I need to order more. Probably will get the same mix of Delta 100 and Foma 100, along w/ some Rodinal for the Delta 100 to see the difference in this subdued light vs the roll that was developed in D76.

Was also going to change the dilution on this last roll of Foma, but decided to do it exactly the same as last time to ck for consistency. Looks the same to me. Same lousy light, same EI, but now w/ scratches and a dog that wouldn't sit still! Focus is off too, but this being the only inside shot I wanted to post it because I really like the blacks.

Whoops, accidentally linked the truck twice and don't know how to delete it w/ the new way things are posted here. Just ignore that. That's it for testing, it works. The next rolls will have the developer dilution decreased to try and get more grain, and then I can finally make some prints.

 

[Don_ih]

Looks the same to me.

Yes, but you can't judge it unless you subject it to thorough scientific testing- and, of course, you weren't supposed to do it at all because [GREMLINS].

Seriously, though - the images look fine.

 

[MattKing]

Fixed the duplicate posting for you. Thanks for the example.