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#51
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Road ruts with Jobo
LABFIX 2 wrote: 2. If you are processing B&W, do not use a stop bath between dev and fix. Why not? I have seen the use of a stop bath cause a blotchy appearance. Most easily seen with high key backgrounds. O.K., but given (1) enough solution is used (and you can use as much stop as you want so I'd use twice the minimum volume) and (2) the stop bath does the same thing the fix initially does, namely stop development, I don't see how uneven development could result. It should take the same amount of time for development to cease via diffusion with either stop or fix steps, so exactly when fixing begins should be irrelevant. OTOH I could see uneven development perhaps resulting if either a plain water stop or too weak a stop was used; or if too little solution was being used for either development or stop. I generally use and recommend a somewhat stronger than normal stop bath for Jobo processing. Personally I suspect "road ruts" is caused by something people are doing with the processor or processing, not the processor itself. So, I agree that with sheet film the expert film drums are best (I use a 3010.) In addition I'd presoak the film, make sure adjusted b&w development times are long enough (several minutes), and make sure (duh...) the processor is perfectly level and the drum rotates properly and consistently (reverse rotation, not one directional.) With the 3000 series film drums it's also important to watch the drum, since the original Jobo motors can stall with these heavy 3000 film drums laden with solution. |
#52
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Road ruts with Jobo
Jean-David Beyer wrote: LABFIX 2 wrote: The volume listed on the tank only indicates the amount of chemistry needed to cover the film. You may need to use more than indicated. (especially with b&w diluted developers) I am not convinced of that. I cannot imagine anyone used a developer until the last few ions are depleted. So if the developer is "too dilute" you just need to develop longer. But there are minimum solution requirements for the drums, and I myself tend to use a bit more than the minimum. Dilution of course is compensated for by time, and I think Jobo has always recommend nothing shorter than 5 minutes for b&w. My suggestions were for people who are having problems. If you get uniform repeatable results, then keep doing what your doing. Cheers! OK: I hope your suggestions are helpful. I have more trouble with people who say you cannot get uniform repeatable results with a rotary processor, or Jobo rotary processors in particular. Maybe they cannot. Let's see: if it is not the earth's magnetic field, is it the phase of the moon? the sign of the Zodiac? ... ;-) Eureka, that's it! Lunar tidal action on the developer! |
#53
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Road ruts with Jobo
Brian Kosoff wrote: However when the subject matter switches to large even white backgrounds, the un evenness is very evident. In regards to perception. I remember talking to the technicians from Sinar about the fact that my expolux shutter was really only accurate in 1/3 stop increments and not in the 1/4 stop increments that were stated in the Sinar brochure. I was told that the motors needed to move a diapraghm consistently to an opening as small as f32 or 45, could not be counted on for that degree of accuracy in 1/4 stop increments. Fair enough. However they went on to say that most people can not discern any differences greater than 1/3 of a stop anyway. This last part blew me away. Every photographer I knew in NYC, either bracketed in 1/4s or push/pulled in 1/4s and it was a very obvious difference to all those I knew, In fact my own e-6 processing was processed in 1/8 stop increments and that difference was clearly discernible to me. Were the Sinar techs lying or in error? Or is it true that most people can not discern differences smaller than 1/3 stop? 1/4 stop is visually evident in transparency films, but pragmatically I see no difference between 1/3 and 1/4. Maybe some of those reporting even processing, that have not used densitometers, are simply not seeing the unevenness? For a 0.05 density difference or less I don't consider it significant regardless of the cause and simply ignore it. There are simply too many variables in photography to pursure that sort of exactness IMO and experience. |
#54
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Road ruts with Jobo
Tom Phillips wrote
Wouldn't it need to be aligned with Polaris to be in perfect "magnetic balance"? Accounting for declination, of course... Our favorite two poles are disintegrating. A third pole has appeared two or three thousand miles from the present South pole. Several other polar regions have appeared. That from a recent Nova program on PBS. Perhaps a celestial "balance" would be better. Dan |
#55
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Road ruts with Jobo
LABFIX 2 wrote: Jean-David Beyer wrote; I always use a stop bath. What is the reason for avoiding it? LABFIX2 wrote; I have seen it cause a blotchy appearance, mosy evident with high key backgrounds. Jean-David Beyer wrote; That is very unlikely. Maybe I should have my eyes checked. And the other 4 photographers that saw the test. What is being questioning isn't what you saw, but what may have caused it. Chemcially, stop bath won't in and of itself cause "blotchy" anything. Using water or too weak a stop, possibly, or some other unknown. I habitually use a somewhat stronger stop with the Jobo. You weren't too technically specific, thus people question. This is a discussion group... Labfix2 wrote; The volume listed on the tank only indicates the amount of chemistry needed to cover the film. You may need to use more than indicated. (especially with b&w diluted developers) Jean-David Beyer wrote; I am not convinced of that. I cannot imagine anyone used a developer until the last few ions are depleted. whatever...I'm not trying to convince you of anything. It's been several years since trying to help folks with processing problems on these newsgroups. Now I remember why I left. My suggestions were for people having problems. If your processing methods work FOR YOU, don't change them. Simple enough. I'll check back in a couple years. You're both about half right. Yes, it's generally (I think) a good idea to use more than the minimum. No, the developer dilution shouldn't matter since regardless you develop to a specific CI using your own time. |
#56
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Road ruts with Jobo
2. If you are processing B&W, do not use a stop bath between dev and fix.
Why not? I have seen the use of a stop bath cause a blotchy appearance. Most easily seen with high key backgrounds. |
#57
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Road ruts with Jobo
Jean-David Beyer wrote;
2500 drums with 2509N reels work fine for me, and give even development. Good for you! I always use a stop bath. What is the reason for avoiding it? I have seen it cause a blotchy appearance, mosy evident with high key backgrounds. I use fairly soft tap water for everything except mixing up PhotoFlo If it ain't broke, don't fix it. I am sure I have read those instructions. But they varied over time. Yes they have. So have films and developers. JOBO has a excellent website that will allow you to find out the most recent suggested procedures. They recommend using enough chemistry, and I use what they say on each tank. The volume listed on the tank only indicates the amount of chemistry needed to cover the film. You may need to use more than indicated. (especially with b&w diluted developers) I get uniform repeatable results with what I have. My suggestions were for people who are having problems. If you get uniform repeatable results, then keep doing what your doing. Cheers! |
#58
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Road ruts with Jobo
LABFIX 2 wrote:
Jean-David Beyer wrote; 2500 drums with 2509N reels work fine for me, and give even development. Good for you! I always use a stop bath. What is the reason for avoiding it? I have seen it cause a blotchy appearance, mosy evident with high key backgrounds. That is very unlikely. It seems to me that, since an acid stop bath stops development by neutralization of the developer much more rapidly than a water bath would do it by dilution, that a stop bath is more likely to be free of blotchy appearance than a water bath would be. And if you skip the stop altogether and go direct from the developer to the fixer, that is really no different from using a stop bath (if you use an acid fix likd F5, F6, etc.) other than compromising the life of the fixer and risking stains. But if you use the fix one-shot, you would not care about the life. I use fairly soft tap water for everything except mixing up PhotoFlo If it ain't broke, don't fix it. I am sure I have read those instructions. But they varied over time. Yes they have. So have films and developers. JOBO has a excellent website that will allow you to find out the most recent suggested procedures. They recommend using enough chemistry, and I use what they say on each tank. The volume listed on the tank only indicates the amount of chemistry needed to cover the film. You may need to use more than indicated. (especially with b&w diluted developers) I am not convinced of that. I cannot imagine anyone used a developer until the last few ions are depleted. So if the developer is "too dilute" you just need to develop longer. This should all come out in the calibrations. In any case, except when I was testing someone's theory of compensation (shown to be incorrect), I tried HC-110 1+31 from syrup, 1+63, and 1+127 and they all developped the film just fine if I developped for the appropriate times. They did not diddle the shape of the film curves (4147 and 4164 Kodak films) as suggested by that someone's theory. I do not know if you consider HC-110 B diluted 1+3 with water to be all that dilute or not, but that is about as far as I go. I get uniform repeatable results with what I have. My suggestions were for people who are having problems. If you get uniform repeatable results, then keep doing what your doing. Cheers! OK: I hope your suggestions are helpful. I have more trouble with people who say you cannot get uniform repeatable results with a rotary processor, or Jobo rotary processors in particular. Maybe they cannot. Let's see: if it is not the earth's magnetic field, is it the phase of the moon? the sign of the Zodiac? ... ;-) -- .~. Jean-David Beyer Registered Linux User 85642. /V\ Registered Machine 73926. /( )\ Shrewsbury, New Jersey http://counter.li.org ^^-^^ 8:15am up 19 days, 19:40, 2 users, load average: 2.30, 2.26, 2.19 |
#59
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Road ruts with Jobo
I think the reason why many people here say that they have even development
is that they are either shooting and processing scenes with uneven, irregular backgrounds which essentially camouflage any un evenness, or they are not perceptive enough to see a difference. Let me explain those statements. First, in most cases on my earlier landscape work, I see very little un eveness except in the event of a very even sky. However when the subject matter switches to large even white backgrounds, the un evenness is very evident. In regards to perception. I remember talking to the technicians from Sinar about the fact that my expolux shutter was really only accurate in 1/3 stop increments and not in the 1/4 stop increments that were stated in the Sinar brochure. I was told that the motors needed to move a diapraghm consistently to an opening as small as f32 or 45, could not be counted on for that degree of accuracy in 1/4 stop increments. Fair enough. However they went on to say that most people can not discern any differences greater than 1/3 of a stop anyway. This last part blew me away. Every photographer I knew in NYC, either bracketed in 1/4s or push/pulled in 1/4s and it was a very obvious difference to all those I knew, In fact my own e-6 processing was processed in 1/8 stop increments and that difference was clearly discernible to me. Were the Sinar techs lying or in error? Or is it true that most people can not discern differences smaller than 1/3 stop? Maybe some of those reporting even processing, that have not used densitometers, are simply not seeing the unevenness? |
#60
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Road ruts with Jobo
Brian Kosoff wrote:
I think the reason why many people here say that they have even development is that they are either shooting and processing scenes with uneven, irregular backgrounds which essentially camouflage any un evenness, or they are not perceptive enough to see a difference. I am not convinced. It is usually true that if I point a camera somewhere, that what is photographed is not all that even, and the unevenness of the subject matter can conceal unevenness of emulsion over the size of the negative (I have never seen that, and imagine it does not occur), unevenness of processing, etc. But the opposite is true, too; some people photograph something like an "even" sky and see a variation. I notice that the sky, even a clear blue sky, is not all that even in practice; at least here in New Jersey. What appears even can vary quite a bit if you actually measure it with a spot meter. It is pretty obvious on the ground glass, too, if you use something like a 90mm lens on 4x5. So just as unevenness in processing can be obscured by unevenness in subject matter, so also unnoticed unevenness in subject matter can mistakenly appear to be the result of uneven processing. I would never use actual negatives (or transparancies) of real subjects to evaluate evenness in processing. For measuring uniformity of processing, you need a means of making uniformly exposed negatives. While not trivial, anyone who is processing his own films is probably able to come up with a means of making such negatives. When I used 6 sheets in the obsolete Jobo reels, the stripe down the middle was about 1/2" or a little more wide and about one zone more dense that the rest of the negative, it was obvious. It would take a very complicated subject to mask that kind of thing. Let me explain those statements. First, in most cases on my earlier landscape work, I see very little un eveness except in the event of a very even sky. However when the subject matter switches to large even white backgrounds, the un evenness is very evident. In regards to perception. I remember talking to the technicians from Sinar about the fact that my expolux shutter was really only accurate in 1/3 stop increments and not in the 1/4 stop increments that were stated in the Sinar brochure. I was told that the motors needed to move a diapraghm consistently to an opening as small as f32 or 45, could not be counted on for that degree of accuracy in 1/4 stop increments. Fair enough. However they went on to say that most people can not discern any differences greater than 1/3 of a stop anyway. This last part blew me away. Not me. I think you and the technicians are talking about two different things. The average user shoots negative film and generally a 1/4 stop error in exposure is not that big a deal. If there were unevenness of development in a single negative of 1/4 stop in an even subject, though, that could be readily perceived. Every photographer I knew in NYC, either bracketed in 1/4s or push/pulled in 1/4s and it was a very obvious difference to all those I knew, Of course, with transparancy films, you do not get much chance to fix exposure errors in the printing step since there is no printing step. In fact my own e-6 processing was processed in 1/8 stop increments and that difference was clearly discernible to me. Were the Sinar techs lying or in error? As I say, I suspect they were neither lying nor in error; they were not talking about just what you thought they were. But you are neither lying nor in error either. Or is it true that most people can not discern differences smaller than 1/3 stop? When I was testing my E-6 processing, with an interest in re-using the chemistry one time, I wanted to see the development time increase required for the second run. The time specified by the processing chemistry did not seem correct. I never finished that testing, but I did notice some things. One is how bad the human eye is in evaluating exposure (no kidding: that is why we use light meters). I made two runs, the second using the manufacturer's recommended time increase. The two transparancies (exposed one right after the other) looked the same to the naked eye. Putting them on a densitometer revealed great difference (part of the subject was a reflecting step wedge). I forget the amount, but perhaps 0.2 density unit. Now IMAO that is really bad processing, I would say. But looking at either transparancy by itself looked fine. OTOH, presented with an image where one half receives 1/3 more exposure than the other is clearly discernable with the naked eye. The eye is very sensitive to differences, especially with respect to things right next to each other, but not very sensitive to absolute values. Maybe some of those reporting even processing, that have not used densitometers, are simply not seeing the unevenness? Possibly. But surely some of the users (e.g., John Sexton) would be extremely sensitive to such problems and would have quit using their Jobo equipment long since. -- .~. Jean-David Beyer Registered Linux User 85642. /V\ Registered Machine 73926. /( )\ Shrewsbury, New Jersey http://counter.li.org ^^-^^ 9:10am up 19 days, 20:35, 2 users, load average: 2.26, 2.12, 2.10 |
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