How many ML of D-76 powder do I mix with how many ML of water.

Photo Engineer said:

Patrick;

CI is just one factor. Grain and sharpness are two others that can change.

You simply don't understand that you are missing critical components of the image here.

PE

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Is there some critical component of this scene that I missed? I captured it in 1971 before I owned a balance while on a photo tour of the future home of the Norfolk Symphony with the conductor and business staff of the orchestra.

Patrick;

There are several things I can say about that picture:

1. I don't have any idea what it would look like in several reference developers
2. I don't have any idea what the developer is you are using, nor what it might be noted from.
3. In the scan it looks grainy and unsharp so IDK what the scan did to it or for it.
4. An isolated photo does not demonstrate any scientific methodology I know of.

Final answer, I can say nothing about an isolated photo like this and cannot tell what you captured or missed. The photo is meaningless. You need side by side comparisons.

PE

It was 400 film, I don't remember which. You know the limits of resolution we can post. You know that scan resolution interacts with grain resolution to make things worse. If it is meaningless, so is your inference that I don'y know a good photograph when I see it. Are you really trying to say that you cannot see the good photo that is hiding in the scan?

One is not able usually to try more than one developer on shots like this while on an assignment like this. Another one on the same roll is the attachment. It is how I knew it was 400 film.

Patrick;

A good photo does not need to "hide"!

You are trying to make some sort of point with these posts of photos, but actually this devolved into a discussion regarding scientific method, I think. As such, your photos signify nothing in terms of scientific method, but are just random isolated points. If you don't see that, then the discussion is meaningless.

You don't know the film, nor the developer and have no comparisons, so what is the point?

PE

gainer said:

Has anyone on this forum actually done an analysis of sensitivity of CI to changes in the amounts of developing agents? Use the "Magic Square" type of experimental plan to get a "ring around" with minimum number of tests.

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In case anyone is interested in what the "Magic Square" that Pat mentions here, it's a really interesting way to design tests. It took me a day to remember that actual name of the test - it's properly called an "orthogonal array test", in the past, a "Latin Square" test, and sometimes called a "Taguchi test" after the person, 田口 玄- Taguchi Genichi, who developed and popularised the method.

It allows one to design a test, say of "X" number of variables, by only performing X+1 tests. For each variable, a high level and low level are chosen. So for say hydroquinone amount in a developer, one amount of hydroquinone is used, and then either a higher or lower amount is used in comparison.

So if you had a developer with 3 things, say 1 g. metol, 1 g. hydroquinone, and 100 g. sodium sulfite, you would then pick another amount for each amount:
Parameter 1 (metol) - Level 1 = 1 g, and Level 2 = 2g
Parameter 2 (hydroquinone) - Level 1 = 1 g, and Level 2 = 2g.
Parameter 3 (sodium sulfite) - Level 1 = 100 g, and Level 2 = 50 g.

You then make an array of these amounts:



You can see how each parameter is varied in each horizontal row. None of the 4 rows are the same. So after you do the test, you have some quantifiable measurement you can do (measure CI, measure accutance, measure resolution) and then you take the results of the measurment on each test, and then you do a few simple statistics (that I don't have the time to adequately describe here) and you can find out which changes in each parameter had the most or least affect on the outcome of the tests.

It's a really powerful system of designing tests and well worth it if you are going to fully explore some of the issues that can arise when testing things. And the cool thing is that it can be applied to any system where you can make changes in parameters and measure the changes.

Pat, after your last two posts, I can only paraphrase a famous H.A.L computer:
"Pat, this conversation can serve no purpose anymore. Goodbye."

Kirk;

We called these "factorial experiments" and we used statistical analyses to look at all of the parameters in the film that I mentioned above and then some. The developer chosen was that which gave the best result in all of the desired characteristics. I have run 12 or more developers in one factorial using several different coatings. The analyses were done by hand until we got enough computer power (and available time on the computer) to do them with a computer.

Variables in the developer included halide, alkali, developing agent(s), and the things we looked at included speed, fog, edge effects, grain and interimage.

PE

Ian Grant said:

Thanks to the French we have the far easier Metric system, which is now International.

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Base 10, horrid! Decimalist! Divisible by 2 and 5. Based on human anatomy, and none too well at that. Possibly the most primitive of all tally systems. Devoid of all thought in it's creation. Foisted on us by a culture that could only count on it's fingers because it didn't have sticks on which to tally and was short of mud and water with which to make tablets.

We only think it has some natural and logical basis because it was taught to us at an early age. It has no logical basis.

If one were to pick a base for a number system 12 would be a logical choice; as would 16 - a convenient 'super-square' of base 2; 60 is hard to beat - it even allows for counting on one's fingers, though you need three hands.

Cultures that put some thought into picking a number system do not choose 10.

The English systems is a mish-mash of bases 12 and 16. My wristwatch works in 60, 12 and five - damn convenient. The calendar in 12 (and 360 if you are a logical Roman and relegate the extra 5 or 6 days to holiday). My computer works in 2/2^8/2^16...

I like using inches and fractions in engineering design - as soon as you realize you are working in base 2 it becomes very easy. However the drawings are in decimal, and you need to know that a hole dimensioned 0.63 is really 0.625 which is really 5/8 of an inch: you won't find an 0.63" drill.

Photography works in stops of base 2 (though I admit to using decimal stops - a real whore-up, but few people can add and subtract in their heads in base 16).

So the idea that the Metric system has any inherent superiority, and that all else is inferior, is nothing but prejudice and as offensive as any other prejudice to people to the people who do not use it. That it is used in many parts of the world is only due to European hegemony. The basis for the system: the distance from the North Pole to the equator - passing through Paris!

Will people still be using base 10 in two thousand years? Possibly not.

For a less rabid discourse: http://www.uog.ac.pg/glec/thesis/thesis.htm - start at Chapter 2: Tally systems

Photo Engineer said:

Patrick;

A good photo does not need to "hide"!

You are trying to make some sort of point with these posts of photos, but actually this devolved into a discussion regarding scientific method, I think. As such, your photos signify nothing in terms of scientific method, but are just random isolated points. If you don't see that, then the discussion is meaningless.

You don't know the film, nor the developer and have no comparisons, so what is the point?

PE

Click to expand...

I didn't say I don't know the developer. I posted the teaspoon formula a few days ago. I do know it was before I had a balance, I do know that whatever variances there were in measurement, they did not cause excess grain or loss of resolution. I do remember that I was money poor but love rich, with a beautiful wife, 6 children, a day job with NASA, a night job with music, and an itch to make pictures. If I let you lead me down this path, it was because you were making unfounded statements about the need for precision in B&W developers.

My last post on this subject is this one. The last photo I posted was scanned from a 35 mm negative. I found the original print I made from it about 35 years ago and scanned a portion of it to show how badly scanning can affect apparent grain.

OK, OK, I know I signed off, but I love a good quote. Here's one for this thread - Clarke's Fourth Law:

"For every expert there is an equal and opposite expert."

Kirk Keyes said:

OK, OK, I know I signed off, but I love a good quote. Here's one for this thread - Clarke's Fourth Law:

"For every expert there is an equal and opposite expert."

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Kirk,
Can you give us the whole list of this guys "Laws" all at once?

Pat,
I think that spoons help when you are in a bind, and have no other choice.

Unless your position is that spoons are the preferred measuring tool, then I cannot understand how this discussion has contined so long!

IMHO

They work and with creativity, can be used to produce 'nice' images, but they are not to be considered the method of choice outside of the kitchen!

I used spoons for about two years while formulating my Root Beer and Earth Soda drinks, but with some very powerful herbs, the flavor was impossible to replicate. Hops were really a pain to measure by the spoonfull if I recall. There was a lot of variation in the particle size and also in the relative importance of the different particles... Never the less, I could turn out a good drink with either a spoon set or the analytical I got later on.

You dont need to prove anything.
People with two good legs often forget how to crawl.

Ray

Ray - http://en.wikipedia.org/wiki/Sufficiently_advanced_technology

Ray Rogers said:

Kirk,
Can you give us the whole list of this guys "Laws" all at once?

Pat,
I think that spoons help when you are in a bind, and have no other choice.

Unless your position is that spoons are the preferred measuring tool, then I cannot understand how this discussion has contined so long!

Ray

Click to expand...

Exactly. Here is what I find comical about this subject. If I whip up a really good developer using spoon meeasurements, and find that I get consistent results from batch to batch, if I spread the good news to others, I will be laughed to scorn if I post teaspoon measurements. On the other hand, if I weigh a number of spoon measurements and submit the average, some will believe that the weights I post are to be used religiously. There will not be one effort to see if there is any tolerance for error. Oh, well.

And formulas calling for 30gm of something, when the original value was 1oz. The difference makes no difference. I am sure a double blind study would not be able to find a 10% variance in the chemistry composition by looking at the prints or negatives.

Nicholas;

A 10% variation in most all film developers, and some paper developers will show a measurable difference to the eye at standard viewing distance. This is assuming identical shots, development to the same speed and curve shape as far as is possible and then making a blind comparison. BTDT from both ends of the experiment - as experimenter with 100 - 200 viewers and as a viewer in the experiments of others.

Oh, and seasoning plays a part in this as iodide and bromide build up differentially with different films in a replenished process or with used developer.

I am really not surprised at all of this debate though as no one seems to do direct comparisons or any sort of scientific evaluation that has any meaning whatsoever.

PE

Photo Engineer said:

I am really not surprised at all of this debate though as no one seems to do direct comparisons or any sort of scientific evaluation that has any meaning whatsoever.

Click to expand...

Hrmppff. That's usually my complaint.

You are right: I haven't varied the amount of M/Q/P/A/C/xyz... in a developer to find the limits of acceptable variation.

OTOH, unless I am doing a controlled series of tests, no two negatives are ever the same, so I would not notice any slight variations in developer. And haven't. Teaspoon measurements are OK by me unless I am doing something critical like paper calibration where I am looking for repeatable results. And even then, next month's run of paper is different and all the numbers are suddenly approximate again.

Nicholas;

Trivializing photo systems engineering causes me great anguish believe it or not. It takes years to learn, there are virtually no courses on it, there are about 200 of us world wide by my estimate and in a previous post, Simon Galley verified that I am probably close in my estimate. When we are all gone and analog is an "old" practice, what kind of legacy would you wish to leave behind? And how would you feel about those trying to be self proclaimed experts who may leave their legacy behind?

I am saddened when I try to post "truth" at least as far as I am capable and, well, you have the same type of complaint about the results.

I am not an architect nor mechanical engineer etc.... So, if I design and build a skyscraper on a fault line, would you like the penthouse suite? Same difference. So, if a mechanical engineer were to post methods of building or improving shutters, I would never dream of posting or commentng on that person's work.

With emulsions, it is difficult to "fake" results. You either have pictures/coatings etc or not! But with developers it seems that you only have to show a single negative to proclaim having found the magic bullet, holy grail or whatever. Well, I worked with Dick Henn, Bill Lee, Grant Haist and others and they all say this: "there is no magic bullet or holy grail". It is hard work and many comparisons of tests.

PE

The point is that we are not talking science here, but
the creation of pleasing visual images, suitable for use in ones home, not in space or emulsion research.

Yes, side by side differences may be detected, but it may be the case that the difference, when viewed seperately, is not significant in terms of acceptability.

Ray;

Good point, but without proof in terms of absolutes here and there, the scientific method developed over the last 100 years or so will gradually fade. And without absolutes here and there, where is the real proof of anything.

PE

We started out explaining why it is not a good idea to use part of a package of any powder developer because there is some probability that any small part of the package will not contain the same fractions of components as the whole. Then the question arose: how does a company like Kodak measure ingredients into a package so that one package is like the next? We don't know for sure, but it was surmised that a large batch of thoroughly mixed ingredients was partitioned into these packages by precisely the same method that we pundits advised against. I then made a comment that perhaps my teaspoon formulas were not so bad after all. Now I am accused of recommending that all research should use volume instead of weight measure.

Even the simple D-23 is a multi-dimensional system. How would we optimize it if we were just starting? First, we have to define "optimum" in measurable terms. Then we must try different combinations of the ingredients until we find the optimum combination. We will probably be working with lab quality ingredients and precision measurements because we do not yet know the sensitivity of our criteria to variations in composition. Let's say that we find that the differences in our criteria over the range of 7 to 8 grams of Metol and 90 to 110 grams of sulfite per liter are negligible, but the true optimim is 7.498 g Metol and 99.2 grams of sulfite. Do we try to convince the production department that each package must have these truly optimum amounts? If we don't tell them we have a nice cushion for error, it will never be sold.

Of course lab work should be done to the best available precision, but it is equally a part of this lab work to establish tolerances. These tolerances in measurement will in fact be determined in a systematic determination of the optimum. I have no idea if anyone actually optimized D-23 in any way, but I do know that I can get the same result, within my ability to discern as a developer of film and printer of negatives , by throwing 2 tsp Metol and 4 tbs sodium sulfite into a liter of water as by carefully weighing out 7.50 g Metol and 100.0 grams of sodium sulfite.

Patrick;

I believe that I dispelled your assumptions about how powder chemicals are made. They are not made by the method you describe, but by the method I tried to explain.

I guess we will have to go with your methodology and use a teaspoon of silver nitrate, a half cup of food gelatin and a tablespoon of table salt in one half saucepan of tap water on the stove to make our emulsions in the future.

And I'm glad that you, a human factors and mechanical engineer are sharing your extensive knowledge of photographic engineering and chemistry with us all. I will not be returning the favor in human factors or other engineering fields as I deem myself untrained and not competent in these areas.

PE

Photo Engineer said:

Trivializing photo systems engineering

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There is a difugalty here:

• Photographic equipment and materials are the product of engineering, chemistry and physics, where rigour and accuracy reign.
• The practice of photography is an art where numbers mean little except as they are necessary to obtain desired results.

It does not diminish the created work if a photographer gets the results he likes by measuring out chemicals as a pinch of this, a dash of that and half a handful of the other.

Don't trivialize the art - without art photography would be a poor stepchild of xerography.

One of the reasons why I love photography is the unique combination of science and art.

The science part is the technical bit, where I can start with materials of high and consistent quality from a reliable manufacturer, together with known and accurate working formulae and methods which will give me a reliable starting point. To me, this is where PE is coming from, and his remarks and explanations on the "science" side do not trivialise the art, which is down to us to apply later.

I sometimes dabble in watercolor painting, and the situation is similar. I buy brushes, paints and paper from one of the well-known artists' supply companies (say Winsor & Newton)....I expect these to be of high quality and consistent from batch to batch, so the only variable is my "art" in using them.
If I mix paints from old household materials and use wrapping paper as the base, I'll get a result, but it will be much more difficult to repeat, will probably fade, and the whole experience will be less enjoyable and rewarding.

Yes, art is important as well as science.

I am trying to explain something that people seem to be missing though. Photo system engineers are a vanishing breed. I am trying to teach correct methods for future practitioners of analog photography so that someday in the future you do not have to reinvent the wheel so to speak.

So, imagine now that you can no longer buy watercolors or even the canvas or paper to paint on. You have to creat from scratch. Well, paints and papers are far easier to create from scratch than analog photo materials. I don't have to care whether analog, as a true science, survives at all, but I do. That is why I try so hard to get this fact understood or someday, someone will be wondering "how did they create these beautiful photos in 2008?"

And, maybe, no one will know! All they will have is Digital which is created by scientists and engineers, not artists. So, I submit to you my suggestion that it takes the proper combination of both science and art with science predominating to create a good photo material and process, but pure art to produce the final picture. Lab technique in processing and printing are also essential in the final stages of this, of course.

Please give some thought to what I have said.

Thanks.

PE

Only an accurate scale will do the job. But developers are cheap and mosty water when diluted.
I got my 0.01 gram scale at eBay and I use it for Pyrocat HD, or add sodium sulfite to Edwal FG7.