Criteria for new developer formulations

Ian Grant · Sep 11, 2009

Keith Tapscott. said:
I`m not quite sure, but I think that the Agfa and Ansco 17 developers are the same formula. The other formula that Ian mentioned was the Adox Borax M.Q.

Agfa Ansco 17 is one that appears to vary from the Agfa/Orwo formula, there are a few that differ, in this case it's actually Agfa/Orwo 44. Agfa's version of D76/ID-11 was Agfa 19 and only differ's by using a small 0.5 g KBr in the initial stock solution which is meant to be replenished.

A big problem is in early Agfa Ansco Formulary it's called Agfa 17, in later GAF Formulary it's called Ansco 17 as they had entirely split from Agfa during WWII, and then a few call it GAF 17..

Thre is a need now that everything is more global, particularly with the internet to be more specific, and personallly I prefer to call them Agfa Ansco or Agfa/Orwo or when identical Agfa/Ansco/Orwo as there are books of formulae published by all 3 companies.

Ian

Terrence Brennan · Sep 11, 2009

BeaverTails

Ian Grant said:
Crumpet/Pikelet (various regional names) in England toasted with butter is an experience you've missed out on then Thomas, kick up another gear

Ian

Try a BeaverTail next time you are in Ottawa: Dead Link Removed

Alan Johnson · Sep 11, 2009

PE;

I have dabbled with quite a few developers and made test prints from negatives of the same subject/lighting/film and am happy I can establish an average metering EI and the relative granularity.Sharpness I am not so sure about.
Can you give the name and approximate cost of the charts you use to assess sharpness and do they come with instructions?
Thanks.

Photo Engineer · Sep 11, 2009

Alan;

The charts come from Edmund Optics/Scientific and come in 2" and 3" size. They also come in negative and positive format. I have neg and pos in 2" for 35mm work. They are part #s DA005E and DA004E. I also have a similar set in 4x5 for use with large format.

The smaller ones are evaporated metal on glass and the larger ones are contact prints on 4x5 film.

You need a negative and a positive set to evaluate the resolution / sharpness properly.

There are no instructions but other than exposure, their use is rather self explanatory. I would be glad to help if you have any problems.

PE

Kirk Keyes · Sep 11, 2009

And after you get the chrome on glass resolution targets, you'll need access to a nice microscope to read the results of your tests.

Photo Engineer · Sep 11, 2009

You could print them with your enlarger. In most cases, you can see the difference in an 8x10 print from a 35mm provided you do a good job enlarging the test chart images.

PE

Alan Johnson · Sep 11, 2009

Many developers add sharpness due to adjacency effects without changing resolution.Can this be detected using these charts?
Dead Link Removed

Photo Engineer · Sep 11, 2009

Yes, adjacency effects can be detected, but a single line is better than line pairs.

Usually, the whole test involves X-Ray exposures and visible light exposures to also determine emulsion turbidity or scatter along with sharpness.

PE

sanking · Sep 11, 2009

Sharpness is a subjective evaluation of image quality based on resolution, overall contrast and micro-contrast from acutance. Resolution, overall contrast and acutance are fairly objective in that they can be measured. Sharpness can not be measured, only evaluated, and for that reason is pretty subjective.

The resolution targets being discussed measure only resolution, when adjusted for the right contrast. They don't tell us anything about acutance, at least without some other form of measurement.

What you will find if you test a given film with a number of general purpose developers is that they all give virtually the same resolution. For example, in my tests of Tmax-100 with PMK, Pyrocat-HD, D76 and Xtol I was able to measure 160 lp/mm to 180 lp/mm with all of the developers. The Pyro staining developers did give slightly higher resolution, but only by about 10%-15%, not significant IMO because in practice the camera/optical system will limit resolution to below 100 lp/mm except with extraordinary equipment and technique.

For this reason I don't find the chrome on glass resolution targets to be very useful for evaluating developers, though they are useful for measuring the resolution of films.

Sandy King

Alan Johnson · Sep 11, 2009

I have the book by Dr Henry,"Controls in Black and White Photography"
He did it-got numerical values for sharpness,three actually,the knife-edge acutance and the adjacency effects for a film/developer combination.The modern way would be to measure MTF I believe.
I believe either method requires a microdensitometer,very expensive.So the objective measurement of sharpness is also a job for the amateur multi-millionare.

Photo Engineer · Sep 12, 2009

There was the very complete treatment given by M. Kriss which i have used before as a reference. It is a lengthy article that wraps up sharpness, acutance, resolution and ties it to micro and macro-contrast in films. And, you are right, a microdensitometer is used to measure these lines. Althouh it has been found that the knife edge is not sufficient, as the center of the line and width are also important. Line spread and line fill are factors in this measurement.

You can view the lines and measure density if you enlarge them sufficiently, but this is just qualitative.

PE

gainer · Sep 12, 2009

Every time we look at a photo and say "My, that's a fine photo." we are making a qualitative judgement. I have a theory that qualitative judgements sell pictures. It is worthwhile to relate qualitative success with quantitative measures but there is no guarantee that there will always be a correlation, or that the most careful and accurate quantitative measures will produce qualitative success. I think sometimes that there is more art in science than there is science in art. Just musing.

Ray Rogers · Sep 12, 2009

The GI advantage

One company I buy Espresso beans from plots acidity, bitterness and sourness graphically and
rates all their coffee beans (not only espresso) on that same circle...
Knowing in which sector "my" favorite coffees fall, allows me to easily ID others that are closely related...

Unfortunately, they won't rate other mfgs coffee for me so I am stuck with their brand or
"blind dating" their competitors.

I appreciate lots of accurate measurements...
but they need to be given a good graphical interface
and universially applied if things are to be made more user friendly.

Art is Skill, Science is Method... Just musing here too.

Photo Engineer · Sep 12, 2009

Another POV on this

I was just chatting in the chat room with some APUG members who asked me some pointed questions that got me thinking. Here is my train of thought based on those questions.......

If I were to come up with a new developer or fixer, people would ask me "what distinguishes this from other developers or fixers, why, and what proof do you have."

In fact, this is true, a new developer or fixer must have a design criterion that satisfies the "customer".

Is it a syrup that is convenient to use? Yes. Is it better than HC-110? Well, if the comparison is lacking we just don't know. This comparison can be fully subjective. If you are happy that is all that matters. But, the comparison should be made before the claims are made.

What if this syrup is 1:1000 and pennies per gallon, but the results look like Dektol 1:1 with some films? This is not a good comparison but illustrates the potential for a weak spot.

So, in the criteria for new developer design, we should be aware that part of the criteria is that the developer equal or surpass some given norm. If that norm is not presented to us, we rely on the originator. That is fine, but if he/she did not do the test, then we are relying on wishful thinking.

If I say a developer is superior to any other developer for grain, then two things pertain. First, this must be something a person desires and second it must be true and provable in most all cases. I say this because I recognize that some films may not function properly with a given developer. If the "customer" wants sharpness, then any other argument I make about grain is useless.

So, here is another POV regarding criteria for developer formulations but from a more subjective view that does not require a multi million dollar investment.

PE

gainer · Sep 13, 2009

Have you ever bought a product on the basis of what the producer wanted you to hear, only to find that it had properties other than those? Truth in advertising is not always taken to mean completeness in advertising. Anyone who thinks I want to sell a thing would be foolish to hire me to test it for him.

As it happens, I enjoy passing on what knowledge I have that allows me to make use of what I may have discovered. If there are other ways to use it, I do not always feel obliged to search them out and test them. I have already given away all the knowledge another person would need in order to do the searching and testing of other uses. Others' uses of what I provide takes no bread from my mouth nor shelter from my head. If it helps provide some of those necessities for them, I feel even better.

To my way of thinking, the simplest way of doing something is always the best. Generally that means that there are fewer things that can go wrong. It may also mean faster, easier to repair and even better. So if I can make a reliable developer with only two components in a solvent (remember D-23?) I will give it thorough consideration, especially if it can be made to have a long storage life.

Sulfite has several uses in photography that are listed elsewhere. It is often the most expensive ingredient in a developer because most times when we think of sulfite, the number 100 comes to mind. But consider, as we have been, a developer stock so concentrated that only 2% or less of the working solution is stock. That 100 gram number becomes 2 grams/liter or less. Most of the effects of sulfite are negligible at that concentration. If it is needed in the stock to protect from oxidation, let us find another method of protection and see what happens to the working solution without sulfite.

If I work on a way to do that, must I examine every known developer that uses sulfite, or might I be allowed to point put a few that I have used and suggest that the general approach might be applicable to others?

Photo Engineer · Sep 13, 2009

It seems to me that anyone who designs a new developer has some criteria in mind to make it special. It therefore also seems natural for that same person to want to see if they achieved that goal, just for the personal satisfaction if not to assure that they did do something noteworthy and achieve the goal(s) set.

After all, caffeinol and other natural product based "developers" work. Wine and urine work. How well do they compare with other developers? IDK and I really don't care as they are for the people who want to do that kind of thing, but if someone wanted me to use one of them and offered a formula, I would ask them "why?" and the answer should include some sort of improved characteristic over what I usually use. I could then agree or disagree with them by running the suggested comparisons myself. But, the key is that the originator must do it first to be in a position to recommend it.

PE

Ray Rogers · Sep 14, 2009

Urwine-76

Photo Engineer said:
It seems to me that anyone who designs a new developer has some criteria in mind to make it special.
<cut>
After all, caffeinol and other natural product based "developers" work. Wine and urine work. <> How well do they compare with other developers? IDK
<cut>
But, the key is that the originator must do it [critical testing] first to be in a position to recommend it.
PE

Agreed, but...

1.
Not all new developers need to be special (read "better").
It is sometimes fun just to do things differently.

2.
"The originator must do it [critical, comparision testing] first to be in a position to recommend it..."

That is if he wants to be consientious and make sure that he isn't just wasting our time, AND
protect his reputation in the process!

Nevertheless the point PE makes here is about what it takes to raise the level of the amateur scientist... not about discouraging experimentation.

---
PS

Anyone have a wine/urine formula?

sanking · Sep 14, 2009

Has Kodak ever published any comparison of their own developers with specific films?

I was just thinking about Ron's comments about criteria for a new developer and it crossed my mind that I have never seen any published comparison of this type by Kodak. Perhaps they published something like this when Xtol was introduced?

Sandy King

Photo Engineer · Sep 14, 2009

Yes Sandy, Kodak does compare and publish comparison data of films and developers. The chart was given here some time ago. Here is the URL, and if you look at the developers for comparison this is taken from real tests.

http://www.kodak.com/global/en/prof...wFilmProcessing/selecting.jhtml?pq-path=14053

When searching for a given film on the Kodak web site, if you look at each film you will usually see comparisons of curve shape, grain and sharpness with a variety of developers.

Before a developer is produced, it must go through a battery of such tests and be vetted by at least 2 if not 3 separate groups, and the same is true of a new film. These products are compared against the specification sheet of the planned improvements to see if the new aims were met.

If not, then the formula is sent back to R&D and the product is not released.

PE

Ray Rogers · Sep 14, 2009

Photo Engineer said:
if you look at each film you will usually see comparisons of curve shape, grain and sharpness with a variety of developers.
PE

Kodak provided lots of information,
but...
I do not THINK I have ever seen more than one curve for any specfic film.

Perhaps there were a few in depth booklets with more, but in most Data Sheets, curves were usually restricted to one developer, wern't they?

Anon Ymous · Sep 14, 2009

Ray Rogers said:
...Perhaps there were a few in depth booklets with more, but in most Data Sheets, curves were usually restricted to one developer, wern't they?

Quite the opposite. I find them the most detailed data sheets around.

Ray Rogers · Sep 14, 2009

Anon Ymous said:
Quite the opposite. I find them the most detailed data sheets around.

What is opposite of what?
I agree!
(some AGFA sheets I have do give as much or more informaton than Kodak's however)
but what about my question?

"in most Data Sheets, curves were usually restricted to one developer, wern't they?"

It is possible I am over looking a big chunk of data.
Do you know a typical data sheet that gives multiple curves for a particular emulsion.
I could be wrong, but think if they exist, they were part of longer more in-depth booklets.

Even so, I don't recall that many off hand.

Anon Ymous · Sep 14, 2009

Tech Pub F-4017 (Tri-X) has characteristic curves resulting with D76, HC110 and Tmax developers. Additionally, contrast index/time curves are provided for several developers and dilutions. The same applies for F-4043 (TMY2).

Add to these lots of information about processing time for different temperatures, and I guess that makes them the most complete data sheets. The only thing they don't list are development times with developers from other manufacturers (Ilford does).

sanking · Sep 14, 2009

When I asked the question about the data that Kodak has provided I was thinking more in terms of visual comparison of grain and sharpness than in characteristic curves and contrast/time charts. The information at Ron's link summarizes what we should expect with different developers, in general, but does not show any specific visual comparisons of grain and sharpness comparing one specific film in different developers. That is the kind of information I would be interested in seeing.

Sandy King

Ray Rogers · Sep 14, 2009

Anon Ymous,

Thanks for those two 2007 pdf links.
I have saved them.

Now if you can only find the same sort of data for all the other Kodak films!

Criteria for new developer formulations

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