Vitamin C in divided developer?

Maine-iac said:

I do. I use pH lab paper rather than a pH meter, but I do know the pH of all the homebrew formulas I concoct. And I certainly agree that pH is one of the more important factors in the success of a formula.

I also agree that there are some developer formulas that demand more precision than others; BUT I have never found one where there was a visible difference, in results from formulas measured with teaspoons and ones measured with a scale.

Measuring with teaspoons is not sloppy; it's not just " a little of this and a pinch of that." Careful measurement and consistency are important for good results. But volumetric measurements are just as legitimate a method as weight measurement, and in the case of some chemicals, may be even better.

Larry

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Larry, pH papers are not very accurate but if it suits you, use them.

I have found over a +/- 20% variation in weight/volume depending on the source of a chemical and its crystal habit. This would translate into Dektol as 2 g/l of NaBr +/- 0.4g or a range of as much as 1.6 - 2.4 g/l of NaBr or 1.8 - 2.2 g/l if you consider 20% to be the total range (depends on what I find with more tests). This is not good for speed or contrast.

I actually have this situation with 2 samples of KBr on my shelf right now. One sample is a very fine powder, and the other is rather coarse. Stacking volumetrically gives different weights for these at the same volume or different volumes for the same weight that differ by over 20%.

If that was the HQ or the alkali, you might be in a lot of trouble. HQ comes as fine powder and rather fluffy needles. They have different weights per unit volume.

PE

Photo Engineer said:

Larry, pH papers are not very accurate but if it suits you, use them.

I have found over a +/- 20% variation in weight/volume depending on the source of a chemical and its crystal habit. This would translate into Dektol as 2 g/l of NaBr +/- 0.4g or a range of as much as 1.6 - 2.4 g/l of NaBr or 1.8 - 2.2 g/l if you consider 20% to be the total range (depends on what I find with more tests). This is not good for speed or contrast.

I actually have this situation with 2 samples of KBr on my shelf right now. One sample is a very fine powder, and the other is rather coarse. Stacking volumetrically gives different weights for these at the same volume or different volumes for the same weight that differ by over 20%.

If that was the HQ or the alkali, you might be in a lot of trouble. HQ comes as fine powder and rather fluffy needles. They have different weights per unit volume.

PE

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I take your point, and I compensate. If I buy a new batch of a particular chemical (e.g. ascorbic acid) and it's in crystals rather than the fine powder of my last batch, I weigh it first to establish a volumetric equivalent. Then I can use the teaspoons knowing that the new batch may be 5g to the 1/2 teaspoon instead of 4g as the previous batch was. I don't assume all things are equal all the time. Over the years, I've learned which chemicals work this way, and since I use a very limited range of chemicals, I know their characteristics pretty well.

For my purposes, the pH papers work fine. Again, I've found that for the formulas I've used, knowing the difference between pH 8 and pH 9 is usually close enough to give consistent results.

Photo Engineer said:

Larry, pH papers are not very accurate but if it suits you, use them.


PE

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Speaking of pH, can anyone suggest the composition of a good solution in which the probes of pH meters might be stored? Hopefully, to be made with substances that many of us would have on our chemistry shelves.

Sandy

Sandy, I use a Hana pocket pH meter with a storage cap at the end for the electrodes. I use Hana pre-prepared solutions for everything.

PE

Sandy, I also use a Hanna pH meter and Hanna Calibration and Storage (buffer) solutions.

http://www.hannainst.com/products/prodline/chemical.cfm

sanking said:

In many formulas with which I have experiemented very small differences in the amount of substances such as potassium bromide, sulphite, phenidone and ascorbic acid can have a really dramatic impact on the results. For example, in a formula that contains pyrogallol or pyrocatechin + phenidone the amount of phenidone needed may be optimized at about 0.01 grams per liter of working solution, and results will be very different if the amount is doubled or halved. How are you going to meausre amounts this small with a teaspoon, even when you multiply them by a factor of 100 to 1000?

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Are you saying that the formula requires just 0.01g of phenidone, or that it should not vary by more than that amount? In the former case, you'd need a scale with better than 0.01g precision to do the job right. With a 0.01g scale, a measurement of 0.01g could be 0.005g, 0.015g, anywhere in-between. That's a pretty wide range. If you're saying that your acceptable measurement error is 0.01g, then plenty of reasonably priced scales will do the job, but even so, not everybody owns such scales.

There are workarounds for measuring items that are required in really tiny amounts, such as phenidone. These workarounds apply whether you're using volumetric measurements or a scale with less than the required precision. The workaround I've seen described is to create a stock solution using quantities you can measure with sufficient precision. For instance, create a 1% stock solution of phenidone in some convenient substance, such as alcohol or propylene glycol. If you mix up enough of this, you can do it with a scale with 0.1g, 1g, or even 1 ton precision. You can then measure the stock solution with an eyedropper, syringe, or whatever. This same approach works if you're using teaspoon measurements of the original solid.

srs5694 said:

Are you saying that the formula requires just 0.01g of phenidone, or that it should not vary by more than that amount? In the former case, you'd need a scale with better than 0.01g precision to do the job right. With a 0.01g scale, a measurement of 0.01g could be 0.005g, 0.015g, anywhere in-between. That's a pretty wide range. If you're saying that your acceptable measurement error is 0.01g, then plenty of reasonably priced scales will do the job, but even so, not everybody owns such scales.

Click to expand...

What I mean is that if you have three three working solutions, one containing 0.005g of phendoine, another 0.01g, and a third 0.02g, there will be big difference in results.

That is in the working solution of course. If we were to mix the phenidone in a stock solution that should be diluted at 1:100 we would need 0.1g of phenidone in the stock solution. If you were to measure that amount with a digital scale with reading to 0.1g, which would be the type scale most people own, the actual amount could vary from as little as 0.05g to as much as 0.15g. That much variation will result in a real difference in results. So you would really need a scale with an accuracy of 0.01 to make this kind of measurment accurately. What sort of accuracy could you obtain with spoon measurments in this case?

I use some of the workarounds you mention, and they are very useful. However, if at all possible I would prefer to just make the measurement directly.

Sandy

sanking said:

What I mean is that if you have three three working solutions, one containing 0.005g of phendoine, another 0.01g, and a third 0.02g, there will be big difference in results.

That is in the working solution of course. If we were to mix the phenidone in a stock solution that should be diluted at 1:100 we would need 0.1g of phenidone in the stock solution. If you were to measure that amount with a digital scale with reading to 0.1g, which would be the type scale most people own, the actual amount could vary from as little as 0.05g to as much as 0.15g. That much variation will result in a real difference in results. So you would really need a scale with an accuracy of 0.01 to make this kind of measurment accurately. What sort of accuracy could you obtain with spoon measurments in this case?

I use some of the workarounds you mention, and they are very useful. However, if at all possible I would prefer to just make the measurement directly.

Sandy

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That is one reason why analog scales that are marked in tenths of grams can be read with considerably less probable error than digital scales that seem to read the same resolution. The lowly powder balance that reads tenths of grains is more satisfactory than many an expensiive digital scale. When the slides are set to read 15.4 grains, an unbalance of less than 0.1 grain will show, and you will be within 1/154 of a gram of the target of 1 gram.

sanking said:

If we were to mix the phenidone in a stock solution that should be diluted at 1:100 we would need 0.1g of phenidone in the stock solution. If you were to measure that amount with a digital scale with reading to 0.1g, which would be the type scale most people own, the actual amount could vary from as little as 0.05g to as much as 0.15g. That much variation will result in a real difference in results. So you would really need a scale with an accuracy of 0.01 to make this kind of measurment accurately. What sort of accuracy could you obtain with spoon measurments in this case?

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Clearly, one needs to pick one's developer before embarking on volumetric mixing -- and one's methods. If you order 100 g of phenidone, and immediately mix the whole amount into stock solution (without any attempt to reweigh what you paid for), you'll likely have better accuracy than you'd get trying to weigh 0.1 g on a scale that's both working near zero and at its precision limit to weigh that small an amount. Of course, 100 g in a 1% solution makes ten liters, which is a lot more than most folks need -- but 10 g, in one liter of stock, is an entirely practical quantity.

Likewise, one would, if concerned about consistency, not try to measure a tiny fraction of a teaspoon -- it's much more accurate to measure a carefully leveled quarter teaspoon, dissolve the powder in water, and then divide the water, than to measure 1/40 teaspoon, and even if you can't store the resulting known strength solution (as, for instance, dissolving ascorbic acid in water), few of our chemicals cost so much that using a gram in place of a tenth is a significant waste (fewer still of those that don't keep in solution).

Going at teaspoon measurement stupidly is surely a reliable method to produce wildly variable results -- yet even that isn't necessarily the kiss of death for everyone. If you goal is to produce smooth, grain-free, contrast controlled negatives with precise densities, variations in developer are a bad thing. If you're shooting with a Holga to begin with, variations in development (within reason) make no difference whatever. And if you need ultimate reproducibility in negatives, you might well be developing by inspection anyway.

I'd like to point out, however, that those who say everyone who mixes his own developers must have a milligram-reading balance, a full set of pipettes, pH meter or even papers, and all the rest of that chem lab equipment come across as simply trying to discourage those on a budget from either saving money on developers, or experimenting with formulae that aren't commercially available. It's quite possible for a worker who's thinking about what he's doing to work accurately enough with simple tools -- and very easy for one who's not paying attention to screw things up badly even with ten thousand dollars worth of lab equipment.

Donald Qualls said:

I'd like to point out, however, that those who say everyone who mixes his own developers must have a milligram-reading balance, a full set of pipettes, pH meter or even papers, and all the rest of that chem lab equipment come across as simply trying to discourage those on a budget from either saving money on developers, or experimenting with formulae that aren't commercially available.

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There is a huge difference in mixing well tested, published formulae, and to purposefully experiment anything in photographic chemistry. Formulae like D-76 and D-72 are quite forgiving in terms of measurement error and you only need a decent balance readable to 0.1g. But some other formulae may be more demanding. To experiment to come up with something better than what's available, you would need more tools and equipment, but what's even more demanding (and expensive) is knowledge and practical sense of chemistry.

It's nothing more than a common sense. Think about it. If you don't want to go to a restaurant to eat. You can prepare an instant ramen noodle in a flimsy aluminum pot that is no good for anything but boiling, the pot which you stole in college dorm, and the product will at least fills your stomach. But what if you want to make truly good ramen noodle of original recipe from scratch? You'll have to select the right noodle, you have to prepare the right stock to make the soup, decide what to put on the noodle, how to season them, etc. You'll need proper kitchen tools, knowledge and practical skills. This approach may give you something better than what's served at a restaurant but surely it's more expensive if you count your investment in setup, education, and your time.

sanking said:

Speaking of pH, can anyone suggest the composition of a good solution in which the probes of pH meters might be stored? Hopefully, to be made with substances that many of us would have on our chemistry shelves.

Sandy

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2.0M KCl solution whose pH is adjusted to 4 to 7 is good. For the pH adjustment, you can use pH 4 buffer (potassium dihydrogen phthalate), pH 6.8 buffer, pH 7 buffer (both containing a mix of potassium phosphate monobasic and dibasic), or boric acid.

Do not allow anything that can potentially harm glass or react with silver chloride to get in the storage solution. Using pure water as the electrode storage solution is probably one of the most common mistake I've seen. It is very bad.

Ryuji said:

Do not allow anything that can potentially harm glass
or react with silver chloride to get in the storage solution.

Click to expand...

That is not to mean I should not measure the ph of
fixers with my accurate to three significant digits
Milwaukee gel probe ph meter? Dan

Donald Qualls said:

Clearly, one needs to pick one's developer before embarking on volumetric mixing -- and one's methods.

Going at teaspoon measurement stupidly is surely a reliable method to produce wildly variable results. . .I'd like to point out, however, that those who say everyone who mixes his own developers must have a milligram-reading balance, a full set of pipettes, pH meter or even papers, and all the rest of that chem lab equipment come across as simply trying to discourage those on a budget from either saving money on developers, or experimenting with formulae that aren't commercially available. It's quite possible for a worker who's thinking about what he's doing to work accurately enough with simple tools -- and very easy for one who's not paying attention to screw things up badly even with ten thousand dollars worth of lab equipment.

Click to expand...

Couldn't agree more. I don't use Holgas; I prefer Rollei's, Fuji rangefinders, and my Wista with Schneider and Fujinon lenses, and Componons in the darkroom. And I don't use volumetric measurements stupidly. I have an old-fashioned powder balance scale that I use to check my volumetric measurements when I need to. And I'd much rather spend my limited photographic budget money on good film, premium fiber-based paper, and good equipment than on fancy pH meters, densitometers, and computer software for charting characteristic curves. A step-wedge and my eyes and a ton of trial-and-error experience behind me tell me everything I need to know about neg density.

Larry

Maine-iac said:

And I don't use volumetric measurements stupidly. I have an old-fashioned powder balance scale that I use to check my volumetric measurements when I need to. And I'd much rather spend my limited photographic budget money on good film, premium fiber-based paper, and good equipment than on fancy pH meters, densitometers, and computer software for charting characteristic curves. A step-wedge and my eyes and a ton of trial-and-error experience behind me tell me everything I need to know about neg density.

Larry

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As photographers we all have different backgrounds, budgets, goals and priorities. How we choose to invest our money and time is a personal choice that can only be understood within the context of many competing personal interests, not all of equal value.

If someone chooses to mix developers to save money, or for fun and entertainment, that is their choice. There is no doubt but that with a modicum of equipment a person can mix some existing formulas that perform as well as commercial versions. Or perhaps even create some new ones that may be as good. However, I agree with what Ryuji said. "To experiment to come up with something better than what's available, you would need more tools and equipment, but what's even more demanding (and expensive) is knowledge and practical sense of chemistry." I would add that it would also be very useful to be a good photographer, with a sound understanding of the sensitometric characteristics of films and of different printing processes.

Sandy

dancqu said:

That is not to mean I should not measure the ph of
fixers with my accurate to three significant digits
Milwaukee gel probe ph meter? Dan

Click to expand...

Correction; that should read: four significant figures .

Also, I should mention www.microessentiallab.com
for the huge selection of ph papers, sticks, calibration
solutions and special testing materials.
Only $5 S&H. Dan

dancqu said:

That is not to mean I should not measure the ph of
fixers with my accurate to three significant digits
Milwaukee gel probe ph meter? Dan

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Probably not.

The vast majority of pH electrodes use single junction Ag/AgCl reference electrode. These types are very easily get shot by silver-reactive chemicals. If you use it very briefly and wash the electrode very thoroughly afterwards, it may be ok for some time, but be prepared to see the electrode going off soon, if you do it repeatedly.

Gel-filled electrodes are also sources of troubles.

Look at my web article on selecting pH electrodes. Kodak publishes analytical procedures for quality controls. The document may not be found on their web (I had to call to ask for a copy.).

sanking said:

I would add that it would also be very useful to be a good photographer, with a sound understanding of the sensitometric characteristics of films and of different printing processes.

Click to expand...

Agreed. But if you broaden the scope like that, I would like to add a sense of choosing problems to tackle. There are unlimited number of problems in the world but only so many are practical to solve, and only some of them are worth dealing with. In other words, I can come up with 1000s of formulae if I want to, but I choose not to spend my time for anything but things I would buy myself if I were buying them.

Most good photographers I know are anally retentive, cheap, and perfectionist (unfortunately, this applies to good scientists I know as well but successful ones know what to give up when their time or power is limited.

Ryuji said:

You can prepare an instant ramen noodle in a flimsy aluminum pot that is no good for anything but boiling, the pot which you stole in college dorm, and the product will at least fills your stomach. But what if you want to make truly good ramen noodle of original recipe from scratch? You'll have to select the right noodle, you have to prepare the right stock to make the soup, decide what to put on the noodle, how to season them, etc. You'll need proper kitchen tools, knowledge and practical skills. This approach may give you something better than what's served at a restaurant but surely it's more expensive if you count your investment in setup, education, and your time.

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But to carry the analogy a bit further, if I'm going to bother to cook for myself, I probably won't want ramen noodles anyway -- those are convenience food (at least for a gaijin like me), like a packaged developer. If I cook for myself instead of just opening a box or bag, I'm more likely to make homemade pizza (though I buy the cheese, sauce, and pepperoni, I do make my own crust), homemade biscuits, waffles, pancakes, johnny cakes, muffins, chili, curry, or even a souffle', than to try to reproduce the commercial packaged food (or developer).

And when I cook for myself, there are some recipes in which I measure with precision (like biscuits, which won't work if the proportions aren't pretty close) and others in which I simply add amounts that experience tells me are correct (like my curry, 100% my recipe except for use of commercial boullion cubes and curry powder rather than homemade stock and discrete spices -- I had to think about it quite hard when making it in order to get amounts and write down a recipe when someone else wanted to try it). I get good results both ways.

Similarly, I get consistently good results with my Caffenol LC+C, now my standard developer for the Copex Rapid microfilm I use in my Minolta 16 cameras. A pinch of this, a quarter teaspoon of that, but the results are excellent -- and consistent, within the means I have to measure. What's the pH? BTSOOM. How many grams of coffee crystals or washing soda do I use? Heckifino. I make it with a cheap set of plastic measuring spoons, in a plastic kitchen-type measuring cup that masquerades as a 250 ml graduate; I stir it with my glass darkroom thermometer. And while the idea of reducing the concentration of a coffee developer to get low contrast results with a document film like Copex Rapid (or Imagelink HQ, where I first tried Caffenol LC) was based on my reading of Anchell & Troop, my trying it and finding my way to good results (in only a half dozen attempts) had nothing to do with expensive equipment.

Okay, perhaps that makes coffee a "tolerant" developer -- and likely it is.

At my level of experimentation, an intolerant one will quickly be put aside, because, for me, it won't work well -- even if you or Jay or someone else comes up with a perfect formula, if it won't tolerate uncontrolled pH or a few percent variation in amounts, it's not suitable for those who can't throw money at this.

Meantime, as long as they keep selling hypo as a chlorine remover for swimming pools and washing soda still sells enough boxes a month to stay on the shelves in the supermarket (I don't see coffee going away any time soon), I'll be able to develop whatever silver halide emulsions I can find to make images on. And I won't need a digital scale that will quit working when the battery becomes obsolete, nor a pH meter, to do it.

Donald, you have some good points. I keep trying to get across to people that sometimes photographic chemistry is more complex than they imagine. Think of a person reading a cookbook and trying to make a gourmet meal vs someone like Chef Emeril Lagasse doing the same thing. There is a world of difference in the effort and result involved.

When I cook simple, it might be a hamburger or just a bowl of ramen soup, as you say, but when I go all out, it may be Boeuf Bourgignon (sp?) or Carbonnade Bruxelloix (sp?) (the French don't care what they say as long as they pronouce it properly anyhow).

Last night it was an all out night with fresh duck breast, and tonight again so we had baked Grouper. I like to do it right if I want the best possible and that goes to both photography and food. (and a lot of other things as well)

To do it right, as you say, it sometimes requires care and other times not, depending on the intended result.

So, doing is one thing, but understanding and projecting into the next level of experimentation is another. Jaydef talks about a fixer formula which he has posted here on APUG. Well, that did not appear out of nothingness. It was the result of several years of work by an entire team of people and their understanding of the chemistry involved. And fixers are a lot less complicated than developers.

You would be surprised at what is yet possible in the field of fixer and developer chemistry if you know what to do and how to do it.

I don't discourage experimentation. I am in favor of it from the standpoint of serendipity, but I find that real discoveries are sometimes difficult to come by unless the approach is Edisonian or the person has a full understanding of the discipline that they are working in and experience in that area, not just book learning. In the former, educated guesses sometimes work, and in the latter, experience lends the edge.

PE

Ryuji said:

Agreed. But if you broaden the scope like that, I would like to add a sense of choosing problems to tackle. There are unlimited number of problems in the world but only so many are practical to solve, and only some of them are worth dealing with. In other words, I can come up with 1000s of formulae if I want to, but I choose not to spend my time for anything but things I would buy myself if I were buying them.

Most good photographers I know are anally retentive, cheap, and perfectionist (unfortunately, this applies to good scientists I know as well but successful ones know what to give up when their time or power is limited.

Click to expand...

Well, I don't think it broadens the scope of this discussion at all to say that in order to design a good developer a person needs to know photography and to understand not only the sensitometric characteristics of films and processes but also real printmaking. It is not all about the chemistry. Photography is as much art as it it science, and irrespective of what some might think, there are signficant differences in results in printmaking between some developers.

Sandy

Ryuji said:

Agreed. But if you broaden the scope like that, I would like to add a sense of choosing problems to tackle. There are unlimited number of problems in the world but only so many are practical to solve, and only some of them are worth dealing with. In other words, I can come up with 1000s of formulae if I want to, but I choose not to spend my time for anything but things I would buy myself if I were buying them.

Most good photographers I know are anally retentive, cheap, and perfectionist (unfortunately, this applies to good scientists I know as well but successful ones know what to give up when their time or power is limited.

Click to expand...

Well, I don't think it broadens the scope of this discussion at all to say that in order to design a good developer a person needs to know photography and to understand not only the sensitometric characteristics of films and processes but also real printmaking. It is not all about the chemistry. Photography is as much art as it is science, and irrespective of what some might think, there are significant differences in results in printmaking between some developers. The fact that some people don't see the difference does not mean they don't exist.

Sandy

Well analogy works only as far as it does, but precise measurement is no substitute for experience and practical skill in baking and pastry making. For example, moisture content of a bag of flour changes all the time, and measurement alone cannot eliminate the consistency problem. You always have to feel the dough and adjust the flour or moisture. I don't make pastries myself but I make bread, hand-made pasta with a rolling pin, and sometimes biscotti. Biscotti is probably the easiest one to get started, but also the hardest one to master. Hopefully, this is usually not the case in chemistry, although this does happen in emulsion making. A trace amount of impurities in gelatin or silver nitrate stock can drastically change the emulsion made from them, in otherwise identical formula.

To be honest I don't consider a bag of instant noodle food, despite the fact that it was a proud invention of the country I'm from... and it was served in the space shuttle for the first time. (Surprisingly, the original inventor of instant noodle is 95 years old and still alive. He even showed up at a press conference of the company which specially made the low-temp version for space shuttle.)

sanking said:

Well, I don't think it broadens the scope of this discussion at all to say that in order to design a good developer a person needs to know photography and to understand not only the sensitometric characteristics of films and processes but also real printmaking. It is not all about the chemistry. Photography is as much art as it is science, and irrespective of what some might think, there are significant differences in results in printmaking between some developers. The fact that some people don't see the difference does not mean they don't exist.

Click to expand...

No disagreement here, it is important to know the material, the process, but also the end products. I was trying to say that the good photographers not only know each of these elements but execute them purposefully, with good focus.

jdef said:

how do you define a "good photographer"? I sense a real disconnect between some of the contributors to this thread. I get the feeling that some believe there is a "correct" approach to photography.

Click to expand...

I define good photographers to be ones who make excellent images that are interesting in many ways, from the original concept, messages conveyed, temporality, spatiality, to good composition, but additionally the work is something that achives the above goal by purposefully executing the skill in manipulating the material.

That is, a good piece coming out on chance basis doesn't count as much. Anyone can do this.

But this is just my definition of good photographer, and ideally, I want to be one some day.

When I form my opinion in my mind, I personally value the original concept and messages conveyed by the images a bit more than other factors. I have more respect for those digicam (or even cellphone) pictures that have good concepts rather than innocuously pleasing photos that can be hung in a corporate conference room (those are usually painting, I know). But this is strictly my opinion.

So, what's your view of good photographers?

Ok, in real life you do not have to make judgement. But if someone put a gun on your head and ask, do you have any idea of good chef, bad chef, ok chef? My definition of good chef is pretty much analogous to my definition of good photographer.

My definition of good coffee roaster? Good vintner? Good inventor?

What about good swindler? (If there is an art in that profession.)

I believe the power of knowledge, skill and experience is best utilized if it is intentionally executed towards the goal directed by the concept that occurs to creative mind. I would call someone who best executes his or her ability a person good in that field. Means may be limited but the emphasis is on the best utility of available means, knowledge, resource, technology, everything. Iron Chef is an example of a brutal implementation of this concept.

This is the criteria I applied to myself when I decided to spend a fraction of my time to learn photography, and also photographic chemistry. I know I'm demanding. But if I weren't, I would learn little.