hitam_jantung

One look at any characteristic curve will show there's one curve produced by one exposure value and one degree of development, from which to calculate a single film speed. You're obviously confused about the differences between negative densities and characteristic curves as they relate to the determination of film speed. Determining film speed based on threshold densities has not been considered reliable in the photo industry for many, many decades, and has been superceded by more reliable methods that better reflect real world use.The standard methods of the modern photo industry are the Contrast Index (CI) method favored by Kodak, and the Fractional Gradient method favored by Ilford. When either method is used correctly to find the speed of films produced by either manufacturer, results agree very closely with the manufacturer's ISO rating. This is no coincidence, but rather sound sensitometric practice at work.If you find manufacturer's ISO ratings "all over the map", it is because your testing is not accurate, and not because the manufacturers can't control the variables of a simple film speed test. These are the leaders of the global photo industry, using state of the art equipment and techniques developed over a century of ground breaking research and development. Your posts show a near total lack of understanding of even basic sensitometric principles and terminology, so it's no wonder your film speed testing results are "all over the map". Contrary to what you may believe, there are a few "right ways", and many, many wrong ways to determine real film speed. You can choose to rate your film any way you want, by some arbitrary negative density, or by the phases of the moon, but don't fool yourself into believeing it has anything to do with sensitometry. Understanding the behavior of my mateials, and the sensitometric principles behind it, comes from many, many years of "making images", and your accusation to the contrary only reveals your own insecurity in your own knowledge. If you don't care enough about the sensitometric properties of your materials to do the reading and learn the methods and terminology, you're certainly under no obligation to do so in order to make images, but if you want to participate in discussions on the subject of sensitometry, and even to offer advice, you should have the common courtesy to do your homework first.

All manufacturers determine film speed by the slope of the toe region of the film speed, but Kodak uses a slightly different method of calculation than Ilford does. Box film speeds do mean something in practice, and it will rarely be found to vary by more than 1/2 stop by competent testing procedures, regardless of which method the manufacturer uses to calculate its film's speed. What "Speed means" is definitely not "up in the air", but specifically defined by repeatable procedures and calculations. When you say that alteration of development changes "the speed of the highlight densities, without severley changing the speed of the shadow densities.", you're not making any sense, in sensitometric terms. There is only one film speed, as there is only one characteristic curve from which to calculate film speed for any given exposure and development. While you may believe that, " what I'm really doing is rating the highlights at a different speed than the shadows.", you're mistaken. You're apparently confusing density with film speed. I don't find that revolutionary, or hard to understand, but simply inaccurate.

The determination of film speed is sensitometric. If you want to discuss it in a way that others can understand, there has to be some concensual terminology. There is only one Exposure Index (EI), or film speed rating for a given exposure, because there is only one Exposure. Film development has no effect on exposure, but it does effect film speed, which is determined by the slope of the toe region of the characteristic curve, by all manufacturers, in one of two slightly different ways. You can't rate your film at any ASA except the one assigned by the manufacturer, which has become ISO. When you rate your film at anything other than its ISO rating, you're using your own EI (Exposure Index). This is standard terminology, and if you use it, your writing will be far more clear, and probably your thinking as well.

The Jobo 2521 tank and reel is far superior to the Combiplan for inversion agitation, and of course, it's also great for rotary processing, which is impossible with the Combiplan. I think nobody mentioned the Expert drums because of the large volumes of solution required for inversion agitation. I've used the Expert drums for stand development with very dilute developers, but not for inversion processing.

William Mortensen was famous for his extended development regimens, and would apparently leave his film in his refrigerator over night. He used a glycin developer, known for its resistance to streaking, and slow working at low temps. I only know one guy who works with anything similar, but I don't think he develops for 12 hours, more like 1 hour, and I don't think he refrigerates.

Minimum volume to cover the film, and minimum volume to develop the film are two different questions. 210ml will cover the film, but whether it's enough to develop the film depends on the developer. Xtol requires 100ml of stock solution/8x10 sheet, so 10 sheets of 4x5 would require 250ml of Xtol stock solution. If you use your Xtol 1:1, you'd need 500ml of working developer, and for Xtol 1:2, as the above poster, you'd need 750ml of working solution, according to Kodak. At 50ml/4x5 sheet, the above poster is using less than Kodak's indicated minimum, which would be 75ml/4x5 sheet @ 1:2. Other developers require more or less stock/sheet,Rodinal, for instance, requires 10ml of stock/8x10 sheet, so a 1:50 dilution would require 500ml of working developer/8x10 sheet, or 1.5 liters for 10 4x5 sheets. 510 pyro requires 1ml of concentrate/8x10 sheet, so when used at the normal 1:100 dilution would require 250ml of working solution for 10 4x5 sheets, just like Xtol stock, and about the same developing time. So you see, it's really a question of capacity at working strength. Developers like Xtol and 510-pyro have a relatively high capacity, so require a relatively low volume of solution to do the work, while a developer like Rodinal has a relatively low capacity, and so requires a greater volume of solution. Large volumes can be problematic with older Jobo units, causing much more wear and tear than designed for. I question the utility of using a developer like Xtol at 1:2, or even 1:1 for rotary processing. If the intended benefit of a dilute developer is increased sharpness due to adjacency effects, or increassed film speed due to compensation, both would be defeated by continuous agitation. If the purpose is economy, it doesn't make any sense at all, since a minimum volume of stock solution is required, regardless of dilution, and that minimum volume meets the minimum volume required to cover the film, I don't see a reason to dilute the stock solution, which would only serve to extend development time?

I assume Jobo's can fail, though I've never seen it happen. I know humans fail, because I've seen them, I've even been them. Human error is the failure automation was invented to avoid. For consistent results, the processing variables must be controlled, as closely as possible. You might think you're better able to control the time, temperature and agitation of your processing than an automated processor is, but I doubt anyone would take you very seriously. You might also think that "personal involvement" imparts some measure of quality to your film processing, but as John Sexton said, "I try to be a robot when processing film, and an artist when printing". A Jobo processor is so far superior to a Kombiplan tank, it doesn't warrant comparison. As far as volume is concerned, one would have to expose an awful lot of film to overload the capacity of a Jobo processor. The truth is that a Jobo processor works just as well at high volumes as it does at low volumes, unlike a large tank, which only works well at high volumes. Little tanks like the Kombiplan are the worst of all worlds, but they do allow for lots of "personal involvement", if that's important to you.

If you want to work outside the bounds of anyone's system, and use your own terminology, that's your prerogative, but you should understand that it makes it impossible for you to discuss methodology with the rest of the world, where some concensus of terminiology is required for meaningful discussion. Your understanding of film speed is unclear, as is your terminology, but what seems clear is that your definition of film speed bears no relationship to fundamental sensitometry, making it all but useless to anyone but you. By the way, Adams didn't invent the Zone System, he adopted it, and popularized it.

Asserting that a replenished system is more consistent than developers used one shot is a sales pitch, and I'm not buying. If one is running a high volume with a very high level of process control, large tanks approach the consistency of one shot developers, but certainly don't excede. For small volume, home darkrooms one shot processing is far more predictable than running a large, replenished tank, in which mix and chemical age are but two of the variables one must control, along with the buildup of development products, evaporation, and exhaustion. All systems that depend on electricity are susceptible to failure, but my Jobo system has a DC failsafe, how about your tank heaters? How about your burst timer? Anyone who claims "zero handling risks" clearly doesn't understand the term, "risk". One can reduce the risks associated with handling films, but never eliminate them completely, regardless of "basic skills", and film hangers are inherently more risky than Expert drums, and further, the basic skills required to use Expert drums are far more basic, and a novice user can expect trouble free loading the very first time he uses an Expert drum. Anyone who hasn't had a problem with film hangers hasn't used many. Your claims might be more persuasive if I didn't have so much experience running tank lines. Even if predictability was a dead heat, handling, versatility and economy are simply no contest in favor of the Jobo. Try switching developers in a large tank line, or worse yet, going from B&W to color neg, or E-6. All easily done with a Jobo, and so impractical as to be impossible with large tanks. Let me guess, you run a commercial tank line? Now who's pitching what? I don't sell anything, or have any stake in Jobo whatsoever. Nice try.

I think so. Even development is the absolute minimum requirement for any processing system. Jobo offers many additional benefits including automation, versatility and economy. My Jobo processor is fully automated, others are semi-automated daylight processors. Once the film is in the drum, the remainder of the processing is carried out automatically, in daylight, with very precise control of timing, agitation and temperature. These processors can process a very wide range of film formats and types, from ULF sheets to sub-mini rolls, in B&W, color print and transparency, and papers as well, with the absolute minimum required volume of chemistry, and developers are used one-shot for the ultimate in consistency. Jobo Expert drums are much easier to load than film hangers, and far less likely to be damaged in the process. If the sole advantage in large tanks and hangers is economy, I'd say it's a false economy, given the large volumes of solutions required, and the replenishment regimes necessary to maintain some semblance of consistency, and hardly worth loading all of those film hangers in the dark, and then sitting in the dark carefully lifting, tilting, replacing for the duration of processing. No thank you. Invariably, by the way, someone will post that they get perfectly even development in trays, with never a scratch in twenty years, and they don't understand why anyone would go to the trouble and expense of using tanks and hangers. I've done it all, and I'll never go back. My Jobo is the best investment I've made in photo processing equipment, and a bargain at twice the money.

Zone-speak is related to sensitometry, but it's terminology is far less clear and useful than the terminology of sensitometry itself. There are no such animals as "highlight speed", "toe speed", "foot speed", "zone I film speed" or "zone VIII film speed". ISO Film speed is determined in a very specific way, as a function of the slope of the toe region of the characteristic curve when developed to a predetermined CI (Kodak). The slope of the toe region of the characteristic curve rises with an increase in CI, to a greater or lesser degree, depending on the developer. Photographers who contact print their negatives in self masking print processes require negatives of very high contrast, and the development required to reach said contrast will inevitably result in an increase in real film speed, or, an increase in the slope of the toe region of the characteristic curve, which translates directly to an increase in shadow density. If you rate your film at EI-X when developing to a normal contrast, the same rating will be too low when developing to a higher contrast, if the goal is to maintain a given shadow density. "Expose for the shadows and develop for the highlights" is a useful rule of thumb, and describes the general reciprocal behavior of film exposure and development, but it's not absolutely accurate. The slope of the toe region of the characteristic curve does indeed rise with development; not in a linear relationship to the highlights, but it does rise, and will manifest as increased shadow density. The most compelling reason to rate one's film at anything other than the box speed is because one intends to develop to other than normal CI, or to compensate for inaccurate equipment, or a special developer. Under anything close to normal conditions, the best course of action is most likely to expose at box speed and develop as recommended by the manufacturer. If one prints digitally, or uses VC paper there is more than enough latitude in the materials to handle quite considerable variations from the mean. Therefore it is only under extreme conditions that one might consider changes to his normal film speed rating, as in the case of the original poster's desire for higher than normal contrast, which would indicate an increase in film development, and a correlary increase in film speed rating, or reduction in exposure. In practice, higher contrast could be obtained by doing either of the above alone. An increase in development without changing the film speed would certainly result in higher contrast, but also in increased shadow density, and in overall density, increasing the appearance of grain and reducing apparent sharpness. Likewise, a increae in film speed rating would also result in an increase in contrast, but with a loss of shadow density and detail, and overall density, producing a thin negative with flat, empty shadows that can be very difficult to print. The increae in contrast obtainable by either means alone is more limited, and less effective than using both in concert. The zone system is a very limited and needlessly obfuscated approximation of sensitometry. Phil Davis' Beyond the Zone System is a far better, and more practical approach to layman's sensitometry. Before anyone gets offended or too proud of either system, remember that it's almost always best to expose at box speed and develop as recommended with a standard developer, and adjust as necessary in printing.

Jobo, assuming the developer is compatible, and most are, to one degree or another.

Remember that real film speed is tied to contrast, so if you want to develop to a higher than normal contrast, your real film speed will increase with the added development,so your film should be exposed accordingly. Overexposure reduces contrast and increases density, which in turn increases graininess and reduces sharpness. To begin trial and error testing, reduce exposure (rate your film higher) and increase development incrementally until you get the results you want. If you want grainy prints, target a low paper grade and if you want less grain, target a higher paper grade for a given contrast.

IR film + lith print. Exact materials used probably no longer available.

It takes about 1/2 hour to make 1 liter of 510-Pyro, which will develop between 200 and 1000 rolls of film, depending on dilution used, and which would last you from 3 to 13 years at 6 rolls/month, with no worries about spoilage or consistency. Economically and mathematically speaking, it's very hard to beat.

TMY-2, without question.

Have you seen this?

 

http://pyrostains.blogspot.com/

 

Exactly what you ask for.

I find the Mamiya 80mmf1.9 a lovely portrait lens, and should cover your sensor nicely. The mount might be tricky?

I was given six 35mm rolls, by three separate parties. I still have two rolls left. How does it compare to TX? TMY-2 is finer grained and sharper than TX, with very little toe or shoulder in the TMY-2 curve, compared to the TX curve. TMY-2 grain, while much finer, is still a T-grain, and looks different than TX grain, when you can see it. If you've used TMX, you can expect a very similar look from TMY-2. The tonality of TMY-2 is the same as TMY, because the spectral sensitivity is the same, and the characteristic curve shape is the same. IMO, most people who have preferred TX to TMY will continue to prefer TX to TMY-2, because they are very different films, and TMY-2 is simply an improved version of TMY, but as Mr. Sullivan illustrates, there will be some converts, probably those who demand high image quality at high EIs. The classical TX shooter who automatically derates his film to EI 200, underdevelops, and restores contrast in printing will probably not see the virtues of TMY-2, especially in 35mm, where overexposure impacts grain and sharpness far more than in larger formats. If you'll pardon the tangient, I think the practices of LF shooters like Ansel Adams and his ilk have corrupted many 35mm shooters. The methods used to secure good printing negatives from LF film are not forgiven in smaller formats. 35mm shooters would do well to look to the practices of sub-miniature shooters, who must learn to optimize their negatives to make even small prints. These shooters avoid overexposure at all costs, and generally prefer acutance developers to solvent-type developers. TMY-2 is a dream come true for this group, giving unmatched speed-to-grain performance. After all, a tripod defeats the purpose of a sub-mini camera, so these tiny negs are made hand-held. If you've never seen a well made print from a sub-mini negative, you might be amazed at what can be accomplished with expert technique. My suggestion, should you decide to try TMY-2, is to expose at ISO 400, and develop in a dilute developer, like Xtol 1:1, or D-76 1:1. I would not recommend HC110 or Rodinal because they offer no improvement in grain or sharpness for the speed loss they cause.

TMY has been my film of choice for many years, and TMY-2 is an improvement. Not a completely different film, it has the same characteristic curve shape, same spectral sensitivity, same recip. characteristics, but it's sharper, finer grained, and a little faster in my testing. No other 400 speed film comes close to the image structure performance of TMY-2, and non-T-grain 100 speed films are only close. As far as I can tell, only TMX and Acros are finer grained, with Delta 100 and Pan F+ coming in a draw. This is an amazing film! If you didn't like TMY's color rendition, curve shape, or processing requirements, you probably won't like TMY-2 either, but if you liked TMY, you'll probably LOVE TMY-2. I do. TMY-2 is the only film I need. Finally.

Truly inspirational.Terima kasih banyak.