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Discussion in 'B&W: Film, Paper, Chemistry' started by claudiosz, May 14, 2005.
Do you have some reference times for fp4 or hp5?
That's an interesting looking formula, Jay. How bad is the fog if you leave out the BZT?
I see hypercat has a similar make up to the old windisch extreme compensating developer(in its use of catechol and sodium hydroxide). Have you thought of exploring its potential as an extreme compensating developer for those high contrast scenes where you don't want the highlights to block up but would also lke full shadow detail. Would there be anyway to make your developer less active or act as a compensating developer but with out the loss of filmspeed.
I did a comparison of Hypercat at 1:1:100 with Pyrocat-HD at 2:2:100. The dilutions were chosen to provide as close as possible the same amount of pyrocatechin in the working solution.
Film was FP4+. The negatives were exposed identically with a light integrator, and were developed together.
Analysis based on blue densitometer reading.
B+F Pyrocat-HD lower than Hypercat, 0.10 to 0.17
EFS Pyrocat-HD slightly higher.
Energy Pyrocat-HD higher, increasing significantly with time
These results do not appear to agree with Jay's findings, but I am confident that they are correct. I draw many conclusions from this test. If you have questions please let me know.
To understand the curves, as you go from left to right the data is 1) time of development, 2) EFS, 3) CI, and 4) value for SBR.
I won't comment on grain and sharpness at this time since this determination will require another test exposing and developing the film in the two developers for the same contrast. My personal opinion is that Jay's Hypercat is much improved over the older formulas that use pyrocatechin + sodium hydroxide, but it is no match for Pyrocat-HD, at least in the area of B+F, energy and EFS.
Should you trust my test results? You decide.
And BTW, regardless of what you think of the developers, you gotta love that long straight linear line of FP4+. The straight line of course in the film, but both of these developers are able to take maximum advantage of it. I mention this because some developers do not.
I also did a test with HP5+ in the two developers, with similar results.
In reply to your comments, in quotes.
It appears that my developer works better for me, and yours works better for you. I don't know how to account for that.
How did you develop your film, and what do you mean by-" The negatives ...were developed together"?
The developing solutions were mixed from the same temperature controlled water, and the negatives were all developed together in individual tubes in the same temperature controlled water bath. It was an apples to apples comparison, if you understand what I mean.
Could you post your data for HP5+?
Yes, I will do that. I may be able to do it tonight, but if not will do so tomorrow.
"I don't need to "trust" your results, as I can perform my own tests in my own darkroom, but your results do provide a basis for comparison.
Of course, you can perform your own tests. You can test until the world turns green. But if you are unable to get consistent results your tests are meaningless. I have absolute confidence tht if I do these same tests tomorrow, the results will be very close to identical.
(The HP5+ files are attached. They were set up for AZO 2 with a ES of about 1.65.)
Seems fair to me.
Let's go for it.
You don't seem to understand. There is no subjective step involved. There can be no bias in exposing film, reading step tablet densities, and plotting curves. You put the step table on the densitometer, take a reading, record it, and enter the value into the graphing program. When you have entered the 21 or 31 steps, and entered the value for process ES and flare, you hit enter and the program produces a curve. How do you figure I might apply bias to influence the program?
Now, if we were to evaluate our negatives in terms of grain or sharpness the element of bias would be more than possible. In fact, bias would be likely in my opinion, because this is a very subjective step and many people see what they want to see.
But to be more precise, my results are more than just my results. They are the result of the application of sound methodology and careful testing procedures, and the results of the test can be repeated with very close tolerance, either by me or by someone else with the proper equipment and understanding of good testing procedures.
The problem here is, simply put, you dont have the skills to maintain consistency in your testing, and that is obvious from the inconsistent results that you yourself have reported.
I would offer to do it at no cost, but I can't promise a very timely turn-around time for it, it would be a month or two... It would be on FP4+ sheet film if that's acceptable.
By the way, what happened to Donald's post from last night that Sandy quoted? Are posts just spontaneously disappearing?
That would be fine with me. I will send you the Pyrocat-HD and Hypercat stock solutions and you can do the comparison on FP4+. FP4+ is one of the best films for this type of comparison because it has a wide range of expansion and contraction possibility.
Given your experience in laboratory work I have a lot of confidence in your ability to establish the proper conditions for a reliable test. The keys of course are, 1) use film from the same emulsion batch that has been stored the same way, 2) exposures must be consistent to at least 1/10 of a second, 1/100 even better, 3) exact control of developer temperature is required, both intitially and over the duration of the time of development. I assume that you have step wedges that can be used for the test?
Just contact me by email at firstname.lastname@example.org and give me your mailing address.
If there is someone else out there with good control of BTZS type testing who might be interested in testing another film let me know and I will send you some of the two developers.
Thanks for the offer on the solutions. I just sent you my address.
I propose that I use tray processing of 3 - 4x5 sheets in 8x10 trays, with these in a 11x14 tray water bath to help control the temp. Processing be around 20C - but identical for each run. I can use the same times that you did Sandy. Mild acetic acid stop bath, pH at about 5.5. Ilford Rapid Fixer at film strength.
I just received 2 - 25 sheet boxes of FP4+ from the same lot that I can use. I assume the boxes have been right next to each other form their entire lives.
I would use my Saunders 4500 fitted with an 80A filter to convert to daylight, a Stouffer 4x5TP step wedge, contact printed. I use a Graylab 900 timer with claims to be accurate to 1/60 sec. Exposure time will be 1 second. That should be more than precise enough.
Sandy - which step wedge do you use? I see you have 3 wedges with numbers on the margin on each edge and the middle of some of the 4x5 sheets you sent me last year. I assume you do this to check evenness, and it also allows you do have some neutral density between the wedges. You find this better than the full frame 4x5TP?
Are there any other conditions that anyone care to specify?
I use tube development, with constant agitation, and develop with the tubes in a water bath, which provides the most even development possible. However, development of sheet film in 8X10 trays should give good evenness as well. The differences between these two developers in terms of energy level, though not subtle, is also not huge, so some degree of attention to detail is required.
My testing also incorporates an 80A filter so we are on the same base there. As for exposure time, one second is too long and will take you into reciprocity with FP4+, which might compromise the results. If possible, adjust the aperture of the lens and don't expose any longer than 0.5 seconds.
For several years I tested by exposing three different step wedges at a time, for the reasons you mentioned. However, I switched to the Stouffer TP 4X5 several years ago and now use it for all of my testing. I have several of these, but one is dedicated to film testing, and I do check the densities from time to time to make sure they are the same as the densities that are used by the graphing software.
Moving away from the issue of testing and back to the issue of the developing characteristics of Hypercat itself ,I want to mention a couple of the reasons why I don't think it is an optimum formula, and both have to do with the choice of activator.
First, sodium hydroxide is a rather nasty thing to work with. It is in fact the chemical that is in Red Devil Lye, and if you read the bottle it says Poison. Now, I am confident that most of us here are able to safely use sodium hydroxide, but if better results can be had with something else why run the risk?
Second, and much more important, is the question of buffering. In a private email with Jay some time ago I expressed my belief that the carbonates are better all around activators for pyrocatechin based developers than the hydroxides, and that one of my concerns was the buffering quality of the hydroxides. As I recall, Jay's response was that he had not seen any evidence of a problem. Well, if you look at the comparison curves I provided of FP4+ and HP5+ the evidence is plainly visible. The developer with hydroxide peters off in activity compared to the one with carbonate. You will see, for example, that the contrast produced by Pyrocat-HD and Hypercat at four or five minutes is very similar, but look what happens with increasing times of development. While the build up of contrast remains very constant with the carbonate developer the one with hydroxide slows down considerably after about six or seven minutes.
Obviously, if ones goal is to design a very fast acting developer that will develop film to a desired contrast within a short period of time one might be able to make a good case for hydroxide, but for a general purpose developer that might be asked to serve a wide range of applications I dont think it is a good choice.
Another and final issue is developer pH. The higher the working pH of a developer the more the film emulsion swells, which makes the film more susceptible to damage. This is an important issue, especially with the east European films, including Efke PL100, that appear to have rather fragile emulsions. The working pH of Hypercat is well over 12, and that is simply much higher than needed with pyrocatechin for most applications.
Toxicity is the least of my problems with NaOH.
I don't know what form you buy it in, but in solid form it's extremely caustic and volatile. The chemical burns it will cause may not even be apparent to the victim for quite a few hours, and they can be quite serious.
Sodium Hydroxide is a substance I simply refuse to have in my house.
Well, I don't agree with you at all. Even if sodium hydroxide is no more dangerous to work with than pyrocatechin, it is a lot more dangerous to work with than sodium or potassium carbonate. It is a caustic alkali that can cause severe skin burns in human beings, and may also soften the gelatin emulsion of film and make it more susceptible to damage. The fact that you have not yet experienced any problems does not mean that the dangers do not exist.
I would also add that high pH caustic developers tend to be unstable, which may well result in inconsistent results. In my experimental work with the Pyrocat-HD formula some years ago the use of hydroxides was the only case where I was unable to replicate results with a second testing with a tolerance of about 0.05 or less.
And the bottom line is that there is no advantage to the use of hydroxide over carbonate, unless extremely short developing times are your objective. If you look at the HP5+ curves in Pyrocat-HD and Hypercat that I posted you will see that they are almost equal in terms of energy level up to about 12 minutes of development, at which point both developers are producing far more contrast than would be required for printing with silver gelatin papers. So what do you gain by the use of a chemical that is potentially dangerous, may cause damage to the film emulsion and is unstable?
As I suggested to you at some point in the past, if the carbonates don't satisfy the requirements of your application you should strongly consider the use of TSP, tribasic sodium phosphate. The pH produced by TSP in a working solution is about mid-way between the carbonates and the hydroxides, but tests show that it has much less gelatin softening effect than the latter. I experimented with TSP while formulating Pyrocat-HD and found that it had many good properties.
I have no personal antagonism toward you, and wonder why you make such a statement? I do believe that you are very sloppy in your work, and I have very little respect for your methodology of testing, and have so stated many times. But this is not a personal issue.
I am aware that some people on this forum appear to believe that you are rather ignorant, petty, nasty and something of a jerk. But whether I agree or don't agree with those opinions is irrelevant. In my exchanges with you I have tried very hard to stick to the facts at hand so as to not to allow my opinion of you as a person to impact my opinion as to the potential of your developers. Granted, this has not always been easy. But anyone with any degree of objectivity who takes the time to read the messages in which I presented my doubts about your Hypercat formula must recognize that the concerns expressed are entirely professional, and can be found in the literature.
I will provide both Pyrocat-HD and Hypercat. Kirk will therefore be free to test the two versions and determine for himself if there is any difference in results. Or, if Kirk prefers, I will send a small quantity of the dry chemicals themselves. He can mix with distilled water since there is no need to mix in glycol when the tests are to be done within the period of a week or so.
This is in fact a important issue because the mixing of these solutions is quite crucial, given the small amount of phenidone and restrainer in the formulas (less than 0.3 g in both cases). Even a 10% difference in weight of either of these two chemicals can have a significant impact on results.
In my own situation I use a scale with accuracy to 0.01 g. Jay has stated that he has a very accurate scale, but given the fact that I am on record with the opinion that Jay is very sloppy I have considerable concern about the reliability of his stock solutions.
Sandy it might be advantageous for Kirk to test yours and Jays Hypercat developers side by side and see if there are differences in thier activity. It might point to a reason for the differing data points.
Basically I am pretty sick of of this developer discussion. I simply noted a contradiction in Jay's results, without in any way meaning for it to become a big deal. But Jay took it very personally and started to attack my work, and that got me going and sucked me into some testing that I quite would rather have avoided at this time.
Regarding your question about Kirk's testing, of course he is free to test whatever version of Hypercat or Pyrocat that he choses.
And this is the last post I plan to make about developers for several months, if ever.
buffering and phenolic hydroxides
Proper buffering is important with phenolic hydroxides, they have a tendancy to oxidize much more quickly at a high ph. This would be consistent with a highly active developer that quickly peters out.
Since we have a system here that is multiphase (the emulsion is a a solid, the base and reducing agent are in solution) we can only push the speed of development so far.
One way of getting around this problem may be to try phase transfer catalysts such as Benzyl Trimethyl Ammonium Chloride or Tetra Methyl Ammonium Chloride .
My grandmother made soap using lye and lard. It is used in many drain cleaners. Most of the others use potassium hydroxide. Some even use concentrted sulfuric acid. Clorox is pretty bad stuff. None of it compares with the dangers of walking across a city street, IMOH.
NaOH is certainly caustic, but I can't see the volatile part. What evaporates from its surface is water.
NaOH is deliquescent - capable of attracting moisture from the atmosphere and becoming liquid. It also combines readily with atmospheric Carbon Dioxide. As the process continues, it forms Na2CO3 - Sodium Carbonate.
Thanks Tom...that was my understanding as well.
If you need NaOH, don't come to my place. Not only won't I have any (or sulphuric acid either, for that matter) but I'll probably be out taking my chances walking across the street.
The proof of the pudding is in the eating, if a formula is good enough it will sell itself, the do everything magic solution does not exist, does it? Or do you know something I dont know and your not telling? Sounds like school yard stuff doesn't it? Some may find it all a bit tedious, others entertaining. I think people who put formulas out there should be able to take both praise and flak, let the people decide, even if in their ignorance they are right or wrong as the case may be. Good Luck, Bogey
Of course. What I meant to say was that if anything evaporates from the surface of a solution of NaOH it is water. Spilling dry NaOH may not be as dangerous as spilling dry pyrogallol.
I can get my lye as well as Grandma's Lye Soap at a grocery store. There are certain food processes that require lye, IIRC. My point was that while you are keeping lye out of your house, don't forget detergents of various kinds as well as other cleaning agents.