K thut trng phimC ba vn c cp trong phn ny. Mt l khi nim v thi gian trng phim tiu chun em li kt qu tt nht trong a s trng hp thng thng v sau y c th iu chnh thch hp hn vi cc ch th khc thng khc. Hai l nhng iu chnh trong qu trnh trng phim: t l ha trn, thi gian, nhit v lc. Cui cng, chng ta xem xt n hm nhanh, hin v ra phim.

Aircraft Graveyard, Slovakia This is Paterson Acupan 200 exposed at EI 160 and processed in Ilford DD-X then printed on Ilford Multigrade Warmtone. It has exactly the vintage look he had hoped for. Leica MP, 35/1.4 Summilux.

The aim of good negative development technique is easily defined, albeit in a somewhat circular way. It is one that enables you to make a good print, easily, on the paper grade of your choice. In one sense, this merely pushes the question back a stage: what is a good print? In another, it gives a very easy guide. We can all recognize a good print when we see one -- or at least, we can tell a better print from a worse print, which comes down to much the same thing. Waterfront, New York There are no absolutes in negative or print quality -- only getting the effect you want. Frances shot this on Fortepan film, which is grainy and not very sharp, but we both love the tonality: it has a sort of 1930s look which we feel suits New York very well. It printed easily onto grade 2 and you can't ask for more than that. Someone else might want finer grain or more sharpness -- so they would do better with a different film and possibly a different developer as well. Camera was a Nikkormat with a 90/2.5 Vivitar Series 1.

what is a good print?This is easier to recognize than to define, and there is a great deal of personal choice involved. Some people have no problem with grain: others are near-paranoid about avoiding it. Some like more contrast; some, less. Some like darker prints; some lighter. This doesn't matter in the slightest. You can decide for yourself which of your prints are better than the others, and work towards producing more prints like that. If your opinions change with time, so can your printing and development technique. There are however three things we would particularly advise you to do. First, pay especial attention to tonality. Some prints 'sing': others, although perfectly competent and with a full range of tones, don't. If yours don't, ask yourself why. Looking at others' prints as well as your own may help you to be more critical. Second, remember that exposure and development are intimately intertwined. Unless you can expose your negatives consistently, in order to get the results you want, you cannot hope for too much from refining your development technique. Third, remember that a good negative is of limited use to a bad printer. Sure, it makes good printing easier, but if (for example) you still 'snatch' a print that is darkening too rapidly, then fix it, wash it and dry it, you are not a good printer. A good printer will throw away the print and make another with the correct exposure. All your photographic skills have to march in step. It's no good being brilliant at developing film but useless at printing, or vice versa. Always work on the weakest link in your own personal photographic chain of quality, whether it is composition, exposure, negative development, printing or anything else. Discarded film hangers we have generally found that if we are going to like a film, we do so from the first roll, almost regardless of developer. This was from Roger's very first roll of Maco Cube 400c, processed in Maco's own recommended developer. Obviously it was just a test roll in the back garden but the promise was visible immediately. KowaSIX, 85/2.8 standard lens.

Be not downhearted, though. The photographic neg/pos process is enormously flexible, and deficiencies at one stage can often be remedied or at least ameliorated at a later stage. For example, you can compensate for under-exposure with a speed increasing developer; or 'pushing'; or printing on a harder grade of paper. the paper grade of your choicePaper grades range from very soft (grades 00 and 0) to very hard (grade 5). Obviously it makes sense to try to produce negatives that print well on the middling grades (2 and 3) because if you do produce negatives that need other grades, this gives you options in both directions. If your negatives always need grade 4, however, you have less room for manoeuvre. The Zone System (there is free module about why we don't use it) aims to produce negatives which always print well on grade 2. Unfortunately this can involve developing each negative separately, to take account of subject brightness range (there is a free module about subject brightness ranges) so it is of limited use with 35mm and roll film. With any system where negatives are developed to 'average' contrast, the aim must be to produce negatives of 'average' subjects that print on grades 2 and 3, leaving the others for unusual subjects. Ruined chapel, Moncontour Ilford XP2 is about as far from the Zone System as you can get: it is developed in the standardized Kodak C-41 system devised for colour negatives. And yet, in the hands of a skilled printer, it can produce results second to none. An 'average' scene requires a harder grade of paper than conventional film, though: typically grade 3 to 3. Genie Anderson used a Leica MP and 35/1.2 Voigtlander Nokton for this shot.

dodging and burningIt is also important to remember that it is not always a good idea to make a print that compresses a very long subject brightness range onto the limited range that can be represented in a print: it just looks muddy and dull. Localized lightening or darkening of the print (dodging and burning) will often look more natural because they reflect the way the human eye works, automatically adjusting its aperture as it looks at light and dark areas. There is a chargeable module on dodging and burning and we are planning one on paper grades. average subjects and recommended development timesFilm or developer manufacturers' recommendations are based on average outdoor subjects, usually for the 128:1 brightness range that obtains around Rochester, New York. If you live further north -- and London is as far north as Edmonton, Alberta -- you may find that you are happier with development times that are longer than in upstate New York, while if you live further south -- California, Greece, southern Japan -- you may prefer shorter times. Indeed the Japanese contingent on the ISO standards committee has lobbied for a lower ISO standard contrast, which would of course mean reduced development times. Likewise, the recommended times will normally give ISO standard contrast (about 0.62) though they may give other stated figures: two popular ones are around 0.55 (lower contrast negatives) and 0.70 (higher contrast negatives). You may prefer either. There is more about all of this in the free module on subject brightness ranges. The manufacturers' recommended times are almost invariably the best starting point. Amend them if you like in the light of your own experience, but no-one else's. Many gurus recommend always cutting the manufacturers' development times, because this gives them the results they like best. That's fine, but we generally find that we get the best negatives -- that is, the ones that print best for us -- with development times that are five or even ten per cent longer than recommended. If we followed their advice we should get hopelessly flat negatives. Anyone who knows what they are talking about (which lets out a distressing number of gurus) knows that the recommended development times are only a starting point and should be varied to suit your tastes. Generally this means making negatives of 'average' subjects that print on grade 2 or grade 3 paper as noted above. Barge museum When Paterson's FX50 came out we started by developing Paterson Acupan 200 (used here) for the manufacturers' recommended times. We got negatives that printed well for us (with our particular equipment, paper, chemicals, preferences, etc.) on grades 2 to 3. Slightly lengthening development times (by about 10 per cent) brought the average grade for an average subject, like this one, to grade 2. Roger used a Voigtlnder Bessa-R with a 50/1.5 Nokton and a 2x yellow filter from B+W.

modifying standard development timesBegin with the manufacturer's recommended times, or with your best guess at the optimum time in the light of experience. If your negatives of your most usual subjects -- whether landscapes, portraits or anything else -- consistently require hard grades (3, 4 and 5) then you are under-developing and you should increase your development times until the majority of your negs do indeed print on 2 and 3. Increase the time in 30 second steps for development times up to 10 minutes, or 1 minute steps beyond that. If your negatives consistently require soft grades (2, 1, 0 and even 00) then you are over-developing and you should decrease your development times until the majority of your negatives do indeed print on 2 and 3. Cut the time in 30 second steps for development times under 10 minutes, or 1 minute steps for longer development times. You should not need to work in 15 second steps, but if you can't decide between (say) 6 minutes and 6 minutes, feel free to try 6 minutes and 15 seconds. Any smaller steps are meaningless in any normal developer for any normal time. negatives and subject matterNote the point made above about your own personal standard subjects. It doesn't really matter what they are. All that matters is that if you shoot different subjects with greater or lesser brightness ranges, you may find that you get better results with different development times: less time for subjects with a long brightness range, more time for subjects with a short brightness range. Non-average subjects might include foggy days, studio shots under controlled lighting, and interiors with light streaming through the windows.

Mono Lake, California If you normally shoot landscapes in sunny California, something like this should be your criterion for negatives that normally print on grade 2 or grade 3 -- but you should be able to see whether other subjects are more contrasty or less contrasty than your usual ones. Frances shot this on Ilford SFX with a red filter, using (as far as we recall) a Nikkormat and a 35/2.8 PC-Nikkor.modifying development times for non-average subjects (and equipment)Most of the time, with 35mm and roll film, you have such a mixed bag of subject contrast on one film that it makes little sense to vary the development time. The only real exceptions are when an entire film is likely to be of subjects of higher or lower contrast. For example, if we go to Greece we may curtail development slightly, while on a misty day, we may prolong it. The Zone System describes an elaborate system for matching development times precisely to subject brightness ranges. You start with your own standard time, described as N or Normal. You then have a series of reduced development times (N minus) for subjects with longer than normal brightness ranges and increased development times (N plus) for subjects with increased brightness ranges. Most people confine themselves to N-2, N-1, N and N+1, but some go all the way to N-6 or N+4. This is not too bad if you are shooting cut film, but otherwise it means carrying multiple backs or camera bodies. If you want to go to such lengths, do not let us discourage you, but we would adduce two arguments for doing it our way instead. First, a foggy day should look foggy and a sunny day should look sunny. Modifying development to such extremes that they all print the same way is not always convincing. Second, with today's range of paper grades at your disposal, you simply don't need to make sure that everything prints on grade 2, unless you are wedded to a particular paper that is available only in grade 2 or in a very limited range of grades. Even your standard development time should allow you to get a good print on one grade or another of paper, and following our 15/50 route will still further reduce the range of grades you need. Small boat, Minnis Bay It is not just 'flat' subjects like this overcast day that demand extra development, but also 'flat' lenses like the uncoated 100/3.2 on the 1930s Plaubel Makina used for this shot. Even developing for twice the normal time didn't do much good, though -- you can see flare reflected from inside the camera on the left and the lack of sharpness makes the image look even flatter than it is. From memory Frances was shooting Ilford HP5 Plus.

15/50The 15/50 route is simply to cut development times for contrasty scenes by 15 per cent, and increase development times for very flat subjects by 50 per cent. These might correspond very roughly to something between N-1 and N-2 on the one hand, and N+2 on the other, but the difference is, you don't do a lot of tests to establish them. Instead you take real pictures of real subjects, which is the only way to become a better photographer. 15/50 is a rough rule of thumb: we make no pretence otherwise. But we also believe that it is more than good enough. If you find that you do better with some other set of figures, such as 10/40 or 20/50, that's fine. But we really don't believe that there is a great deal to be gained by going much further. pushingPushing is no more and no less than over-developing. This gives you more contrast, and more contrast at the thinnest end of the negative (the shadows) corresponds to more speed. As soon as you develop to a different contrast from what is specified by ISO rules, you are no longer talking about ISO speeds but EIs or exposure indices. The degree of pushing that is possible varies greatly: Low-contrast scenes can be pushed a lot further than high-contrast ones, because the contrast is low to begin with. Some films push more gracefully than others, before becoming too contrasty or too foggy: most 'old technology' films (Ilford's Plus series, Kodak Plus-X and Tri-X) push better than their 'new technology' counterparts (Ilford Delta, Kodak T-Max), though the special 'push' films (Delta 3200, TMZ P 3200) give the ultimate in speed. Bristol lad In the 1970s Roger used almost always to overdevelop his favourite film, Ilford HP5. This gave a wonderful 'mean streets' gritty look but unfortunately he was also inclined to under-expose, resulting in empty shadow areas in all too many of his pictures -- which is why this one is run so small! Nikon F, 21/4 Nikkor (the old 'mirror up' lens) with red filter.

Some developers deliver more speed than others, so you don't have to tolerate as much contrast from overdevelopment. For example, Ilford HP5 Plus in Paterson FX-50 is as close as makes no odds to ISO 800, so EI 1000 is a 1/3 stop or at most a 1/2 stop push, necessitating a very modest increase in development time and a minor penalty in contrast. With Perceptol or another fine-grain developer the true ISO might be 250 so EI 1000 would be a 2-stop push. D-76 is a good push developer but as it gives only about ISO 500, EI 1000 would be a 1-stop push. Then there is personal preference, and the question of what is acceptable to you. If you are looking only for recognizable faces, as you might be for surveillance photography or at some kinds of rock concert, you could probably rate HP5 in FX-50 at EI 2000 or more -- but you wouldn't have any shadow detail. As a very general rule, adding 50 per cent to development times doubles effective film speed (+1 stop), while doubling development times quadruples it (+2 stops). This is such a wild generalization that the manufacturers' specific recommendations are far more useful but it gives you an idea of the orders of magnitude involved. Now it is time to look at the variables involved in developing: the actual mechanics of the process.

Ruin, Pelopponese Frances, who shot this, does not like it as well as Roger does; he really likes the tonality, which for him is the most important attribute of any film. It was one of our first shots on Paterson Acupan 200, developed in FX39, and it printed well on grade 2 despite being a fairly contrasty subject. Subsequently we increased the development times for 1 minute for subjects shot in duller climes such as England. Nikkormat, 35/2.8 PC-Nikkor.

development techniqueThere are four variables in negative development technique: concentration, temperature, time and agitation. The most important single consideration in all of them is consistency. As soon as any of them varies, you will get a negative that looks different and prints differently. To make deliberate changes, you should ideally alter only one at a time, leaving all the others the same. In practice, many photographers do not do this, and it does not necessarily matter all that much. Photography is more like cookery than rocket science, and if you have a fair idea of what you are doing you can change two or more variables at a time and guess with reasonable accuracy which variable produced which result. It's also true that there is a fair amount of flexibility built into the system. You have to go quite a long way from the optimum concentration, temperature, time and agitation before you get a negative that is unprintable, and the range of negatives that qualify as 'excellent' can still be produced over a range of conditions. compensating one variable with anotherTo a very considerable extent, you can compensate for a change in one variable by making a compensatory change in another. For example, if you use a weaker developer (a lower concentration) or work at a lower temperature, you can compensate by increasing the development time or agitation or both. On the other hand, these compensations are seldom exact. In many cases, it is actually impossible to get exactly the same combination of speed, grain, sharpness and contrast by making compensatory changes, and even where the combination is identical or near-identical the tonality may vary. This is why so many photographers swear by their method alone, though all that this normally means is that they have arrived, more or less by chance, at a way of working that suits them. Other ways of working might be as good or better -- or, of course, worse. Girl, phone, train Voigtlnder's 75/2.5 lens is not what you might call fast, so fast films are essential when there is not much light -- the more so when, as here, the picture was taken on a moving train, necessitating a short shutter speed to stop camera shake. Although we used to push Kodak TMZ P3200 to 12,500, and although Ilford Delta 3200 is even faster and pushes even better, we generally prefer to rate Delta 3200 at 3200 (as here) or below because the tonality is so nice, especially in Ilford DD-X -- better than TMZ at any speed, high or low. But others prefer the sheer speed they get with longer dev times. Roger's camera was either an M4-P or a Voigtlander Bessa-R.

1: concentrationA strong developer works faster, and oxidizes more slowly, than a weak one. In one extreme, a weak developer may oxidize to uselessness during the course of development. At the other, one reason why powdered developers were often made up as stock solutions to be diluted for use is because they keep better that way. As already noted, you can compensate for reduced concentrations by increasing development times, but it may be difficult or impossible to replicate the results obtainable with a higher concentration and a shorter development time. The main reasons for diluting developers below their normal strength are to lengthen inconveniently short development times (see below); or to get a compensating effect (see below); or for economy or simply because you are running out of developer. At traditional concentrations, the relationship between concentration and developing time is not linear. For example, diluting Kodak D-76 to half-strength (1+1) may entail as little as a 10 per cent increase in development time, though it might be as high as 30 per cent, depending on the film. Only when the developer is very weak to begin with are you likely to see more or less linear relationships. For example, many Paterson developers are diluted 1+9 for normal use but may be diluted to 1+14 or even 1+19, in which cases extensions of 50 and 100 per cent respectively are counselled. Ramsgate Customs House As well as establishing a personal development time you have to establish a personal film speed and you may also have to juggle the dilution in the name of tonality. This was one of Roger's first shots on Fuji Acros (ISO 100), rated at 100 and developed for the recommended time in Paterson FX39 1+9. Eventually we had to drop to EI 64, developing in 1+14 or 1+19 for extended periods, in order to get both shadow detail and tonality that we liked. Alpa 12 WA, 38/4.5 Zeiss Biogon, 44x66mm format.

re-use, replenishment, one-shotThe traditional approach was to make up a volume of developer; put a number of films through it; and then throw it way. Fairly obviously, if you re-use a developer, its concentration and indeed its chemical composition change each time you put a film through it. You can compensate for this by increasing the development time, but clearly, you can never compensate exactly. A better approach is to use a 'seasoned' developer. This is one which is re-used, but which is also re-activated by the addition of replenisher. A replenisher is essentially a rather concentrated version of the original developer, added either as a simple top-up to maintain the original level or on a more methodical basis, running off part of the used developer at fixed intervals (usually after a fixed number of films) and then replacing that with replenisher. A 'seasoned' developer is much more consistent than one that is re-used without replenishment, and can be extremely economical, but it is likely to require a longer development time than fresh developer and film speed will be lowered because of bromide build-up. Best of all is to work 'one-shot', making up fresh developer (from a stock solution or from raw chemicals or prepared powder), using it once, and throwing it away. Barring deterioration (by oxidation or hydrolysis) of the stock solution, this guarantees the maximum possible consistency. Decanter Studio still lifes are an excellent way to experiment with different developers, concentrations, etc. You can still aim for great pictures, and if your new development technique lets you down then you have not lost potentially irreplaceable pictures, as you might if you went out shooting for the day: testing untried film-dev combinations on important or interesting subjects that you can't re-shoot is rash, to say the least. This was a technical exercise shooting 6x7cm Ilford Delta 100 for enlargement to whole-plate size (6 x 8 inches, 168x216mm, a mere 3x enlargement, to try to get contact-print quality. Roger used a Linhof Technikardan with 210/5.6 Rodenstock Apo-Sironar-N and processed the film in Ilford DD-X.

2: temperatureThe standard temperature for black and white film development used to be 65 F, 18 C; then it rose to 68 F, 20 C; and many people today work at 75 F, 24 C. Within this range, it is possible to compensate reasonably well for variations in temperature by changing the development time: higher temperature, less time, lower temperature, more time. Most film and developer manufacturers publish tables to accommodate different temperatures. Even so, there may well be small variations in developer performance, especially with developers containing two or more developing agents, because of the different sensitivities of the developing agents to temperature. At lower temperatures, development may slow unacceptably or cease entirely and variations in contrast and tonality may become more obvious, while at higher temperatures there is an ever greater risk of fogging as well as the possibility of variations in contrast and tonality. Take the temperature high enough and the emulsion may also become excessively tender or even float off. Variations of +/- 1 F, 0.5 C, are generally regarded as trivial but if you can work to greater accuracy, it will do no harm. Most thermometers are coinsistent to +/- 0.5 F, 0.25 C, and consistency matters more than accuracy. If you always develop at the same indicated temperature using the same thermometer, it does not matter very much whether the thermometer is reading high or low. It is a good idea to get used to taking the temperature of the developer just before you tip it in, and just after you pour it out: the variations may surprise you. When you have a good idea of what they are, you can try a 'fly by' technique. On a cool day, you put the developer in a little warm; and a warm day, when the temperature may rise above the aim point, you put it in a little cool. For maximum consistency, use a bath of water at the aim temperature and stand the tank in that whenever you are not agitating it. Rusty car, rural France We habitually develop our films at 24 F, 75 C, but with Paterson Acupan 200 (as used here) we normally stick to 20 C, 68 F, because the emulsion is loaded with development accelerators and development times become dangerously short, leading to a risk of uneven development. Another way to lengthen development times is with increased dilution. Frances shot this with (as far as we recall) a Voigtlnder Bessa-T and 50mm lens with 2x B+W yellow filter.

3: timeAs with temperature, what is important is consistency -- though very few timers are inaccurate enough to make any difference to timing accuracy. A purpose-made stop clock is much pleasanter and easier to use than a wrist-watch or kitchen clock. A useful alternative to a clock is a tape-recording of the processing sequence. This makes it much harder to forget anything or to lose your place in the sequence and even allows you to work in complete darkness. Times under about 5 minutes can lead to risks of uneven development -- work at a lower temperature or a higher dilution, or use a processing machine such as a Jobo CPE-2 -- while excessively long times are boring and are unlikely to bring any benefits. Some people advocate 'stand' development, with times of half an hour and more and agitation every few minutes, but few if any of them seem to produce pictures that are any better than those produced by countless other photographers who use much more conventional techniques, so why bother?

Three generations, Weston-super-Mare The heads of the two women are poorly differentiated from the background, but this is not primarily a development fault: the tonality in the flesh tones is excellent. Rather, the problem is one that is common to beginners: under-exposure leading to poor differentiation in the dark areas. There is also excessive contrast as a result of over-development: the light dress of the woman on the right is almost 'blown'. Roger, who shot this in the early 1970s, used habitually to rate Ilford HP5 at 1000-1600, with totally inadequate metering technique, because he didn't know any better. Today he would give at least a stop more exposure and probably 20 to 40 per cent less development time. This might have been shot with any one of a wide range of cameras: Pentax SV with 55/1.8 Super-Takumar, Nikon F with 58/1.4 Nikkor (the likeliest) or any one of a variety of pre-war Leicas with 50mm Elmars.

timing the filling and emptying of small tanksMost people use small film tanks nowadays, that is, tanks that hold the film on a spiral and have a light-trapped lid through which the developer, etc., can be poured in and out. Obviously it makes sense to fill the tank as quickly and smoothly as possible. It does not matter whether you start the timer as you start to fill the tank, or when it is full, but you need to choose in the interests of consistency. Another possibility is to work partially in the dark. Have the tank full of developer (not to the brim, for obvious reasons) and lower the freshly loaded spirals into it on a spindle. Then put the top on and work as normal in the light. This gives very quick, even immersion. It is a good idea to start to pour out the developer some 15 seconds before the end of the developing time. That way, the short stop or fixer can be added promptly, bringing an abrupt and timely end to the development time. Alternatively, again, you can have a second developing tank ready, full of fixer. Astonishingly, you can open the lid of the developer tank in full light; lift out the spirals; and drop them in the fixer tank before putting its lid on. This used to be an Ilford party-piece. The secret is that the induction time for the new exposure is less than the time it takes to get the film in the second tank. Even so, we have never been brave enough to try it: we'd rather do it in the dark, or drain and fill conventionally. development times and contrastThe longer the development time, the greater the contrast. It's as simple as that -- up to a point. Sooner or later, any given film-developer combination reaches gamma infinity. This is the point where the highlights are as dense as they can possibly be, but development continues in the shadows and fog continues to rise. The inevitable result is that contrast slowly declines, as the fog and shadows gain density and the highlights don't.

Volunteers, Draper's Mill This is a fairly contrasty subject to begin with, so you do not want to make matters worse by over-developing. Much better to use a fast lens (here, a 35/1.7 Ultron on a Voigtlander Bessa-R) and a film that is fast to begin with and does not build contrast too fast on being pushed: here, Ilford Delta 3200 at 3200 in either Ilford Microphen or Ilford DD-X (we do not recall which). Roger.4: agitationThe purpose of agitation is to carry away the waste products of development and to bring fresh developer into contact with the film. Beginners often underestimate its importance, giving the tank the occasional shake when they think about it, but at the other extreme, some experienced photographers get rather more excited about it than they need to. Insufficiently frequent agitation can lead to bromide streamers, where bromide liberated by development sinks slowly below the development site and inhibits the development below it. The trouble is, no-one can exactly quantify 'insufficient agitation'. Anything less than a couple of inversions or twists per minute is running a risk, but with weak developers and long development times, you may be able to use as little as one inversion or twist every few minutes. Reduced agitation must be compensated for by increased development time but anyone who is interested in such faddish agitation techniques will probably be interested enough to do their own development time testing anyway. Constant agitation gives the most rapid development and the maximum toe speed (see ISO Film Speeds, free) for a given contrast. It also gives the most even development for short development times. Compared with the manufacturers' recommended development times, which normally assume intermittent agitation, you should reduce your development times by 10 to 15 per cent as a starting point. In between, there is a wide range of what is desirable, acceptable or recommended. The two most common regimes are 5 seconds agitation every 30 seconds or 10 seconds every minute. Minimal agitation -- 5 seconds per minute -- favours acutance developers but unless you are using an acutance developer it probably doesn't matter very much what agitation regime you use, as long as it is consistent. Draper's Mill When you want the maximum possible shadow speed at a given contrast, constant agitation is a good idea. Some will tell you that over-agitation spoils tonality. We disagree. Fortunately you don't have to take anyone's word for it; for the price of a couple of rolls of film you can find out for yourself. Roger loaded his Voigtlnder Bessa-R with Ilford Delta 3200 and shot with a 35/1.7 Ultron.

agitating small tanksWith almost any agitation regime using small tanks, it is normal to bang the tank on the table a couple of times after filling, to dislodge air bubbles, and to agitate continuously for the first part of the development, typically for 30 or 60 seconds. The main ways of agitating small tanks are by twisting and by inversion. Twisting is normally used with tanks that leak when inverted, but it is not in the least inferior as a means of agitation provided it is reasonably vigorous and the spindle is twisted in both directions. Twisting in one direction only brings a slight but non-negligible risk of agitation marks as a result of developer streaming past different parts of the film at different speeds. Inversion agitation is normally carried out at about one inversion per second. A tank that is part-full, with an air space over the developer, agitates much more efficiently than one which is full to the brim. For an analogous demonstration, take a full, unopened jar of orange juice and invert it. Note how fast and how much the juice mixes. Now open it, pour a small glass, and replace the top. Invert again. Note the difference. agitation in deep tanksThere are at least three ways to agitate film developed in deep tanks on hangers or racks. The one used in most professional lines is nitrogen bursts at fixed intervals. The most practical for most people is a reasonably vigorous up-and-down shake, combined with a twist if you are talking about spirals on a single core. And the traditional method with sheet film was to lift it out of the tank; tilt it so that it drains from one bottom corner; and then put it back in some five seconds later. Next time, drain it from the other bottom corner. agitation in traysSome photographers successfully develop several sheets of cut film at a time in trays. The trick is to pull off the top sheet; slide it under; and repeat. We have never got the knack. We prefer to develop one sheet at a time in a Nova deep slot tank, or to use a rack to develop 4x5 inch film. If we use a tray, we develop one sheet at a time, rocking the tray for agitation. agitation in paterson orbital tanksThese can be a very good way to develop cut film: one sheet of 8x10 inch or 18x24cm or whole-plate; or up to two sheets of 5x7 inch, 13x18cm or half-plate; or up to four sheets of 4x5 inch or 9x12cm. The amount of developer needed is tiny and once the tanks are loaded, you can use them in daylight. It is a good idea to roughen the bottom of the tank so that the film does not stick to it, and we no longer recommend the use of the power base as it has on occasion led to uneven development thanks to unidirectional agitation. We now recommend using the manual base and agitating the tank as randomly as possible. Dean Roger used an 8x10 inch De Vere for this shot, with a 21 inch (533mm) f/7.7 uncoated Ross lens and Thornton Pickard shutter. The film (Ilford HP5, from memory) was developed in a Paterson Orbital using the power base and you can see an agitation line beside Dean's right cheek.

short stopWith the exception of amidol (which will continue to work in a weakly acid envirinment) all practical developers are alkaline: in an acid environment, development stops immediately. A short stop is a weak solution of a weak acid, usually acetic or citric, to bring this about. A typical concentration is 2 to 5 per cent. Stop-baths can be re-used until they are neutralized completely by developer carry-over: test with litmus paper or use a commercial stop bath with an indicator dye that changes colour (usually from yellow to purple) when it is exhausted. Or make up fresh -- it's hardly expensive. Some photographers always use short stops; others never use them. They can prolong fixer life slightly, and if you are photographing dead flat grey cards you may find that you need a short stop in order to get an absolutely even tone, but any unevenness will be lost in any real-world subject. We use them with paper but not with films. Use the short stop (if at all) at more or less the same temperature as the developer: +/- 2 C, 5 F shouldn't matter, but closer is better. As little as 10 seconds is fine; anything over 30 seconds is pretty much a waste of time. Agitate constantly. Popeye Village, Malta This is fairly typical of the sort of subjects we shoot: rather off-beat travel images, in this case at the old Popeye movie set near Mellieha Bay, Malta. It's one of our favourite films (Paterson Acupan 200) and one of our favourite developers (Ilford DD-X) but it was also one of our first rolls with this combination and it is under-developed and therefore somewhat flat. Roger used a 12/5.6 Ultra-Wide-Heliar, probably on a Voigtlnder Bessa-R2.

fixingFixer removes the undeveloped silver halide (see the free glossary) from the film. An unfixed or inadequately fixed film is milky and will eventually darken and stain. Use the fixer at more or less the same temperature as the developer and (if used) the short stop: the closer, the better, but +/- 2 C, 5 F should not matter. Agitate at least as often as for development; constant agitation will do no harm. Most fixers today are rapid, acid fixers. They may or may not contain hardener. Rapid fixers are based on ammonium thiocyanate rather than potassium thiosulphate, and work a lot faster. Their only disadvantage is that they are more expensive. Acid fixing baths are usually a good idea, especially if you do not use short stop, as they arrest the development immediately. With staining developers, however, the fixer diminishes the stain so a neutral or even alkaline fixer is better. Hardening fixers are almost never necessary with modern materials unless you are processing at very high temperatures: modern emulsions are much better hardened than they used to be. A major disadvantage of hardening fixers is that they greatly prolong washing times. This is why we never use them. Cell Block 9 A lot of nonsense is talked about over-fixing. Yes, you can do it -- but it takes maybe 10x as long as the clearing time before you get the slightest losses in the shadows with any normal film and fixer. The same applies to 'blix' with Ilford XP2, which Frances used for this shot. The silver image is bleached at the same time as the unused halide, leaving only a dye image and it does no harm to 'blix' for twice as long as recommended. Voigtlnder Bessa-T, 50/1.5 Nokton.

fixing timesThe quickest, easiest, most reliable and safest way to establish fixing times is with a scrap of unprocessed film of the type you are processing. With 35mm, the torn-off leader is fine. With 120 or cut film you may care to cut up a roll or sheet and keep the pieces in a box. It does not matter if the film is exposed to light. Place a drop of fixer at working strength on the film. Leave for 20 to 30 seconds. Drop the piece of film into working strength fixer. Time how long it takes for the spot to become invisible. This is the clearing time. The reason for using the spot is that it is much easier to judge clearing by comparison than by looking at a piece of film without a fixed spot. Fix for two to three times the clearing time, though longer (even 10x) will not do any harm: it takes grievous over-fixing before the image is attacked. Re-use the fixer, repeating the test each time, until the clearing time is twice the original clearing time when fresh. This still leaves a good margin for safety: you could go to three times and still be reasonably safe. washingMost people over-wash films, wasting time and water. Washing is a simple diffusion process, and surprisingly quick. The most efficient method uses several changes of water, rather than running water. Each change to fresh water quickly reaches equilibrium until the fixer levels in the film are negligible. Some years ago, Ilford devised a means of rapid washing that uses very little water when using a non-hardening fixer and processing in small tanks. Fill the tank with water at the same temperature as the fixer. Invert 5 times. Drain, refill and invert 10 times. Drain, refill and invert 20 times. The film is now (believe it or not) washed to ANSI archival standards. If you can't believe this, repeat any one or more steps. It won't make any difference but it will make you feel better. Do not believe some 'authorities' who tell you that you have to leave the film in the water for 5 minutes between washes; we have this on authority from the Ilford personnel who conducted the original tests. In trays, deep tanks or buckets (with films on racks), with a non-hardening fixer, try 6 changes. The first is just 10 or 15 second rinse. The second and third should be 30 seconds each; the fourth and fifth, one minute each; and the last, two minutes. With a hardening fixer, follow the manufacturers' instructions. wash testingThe classic residual hypo test is carried out with Kodak's HT-2 residual hypo test solution, which is 44ml of 80 per cent acetic acid (36 ml of glacial) and 7.5g silver nitrate. Mix in about 750 ml of water (remember -- Always Add Acid To Water) then make up to 1 litre. Store in a brown bottle away from light. Cut off a bit of clear film and immerse it in the solution. A well-washed film should show little or no discolouration. This solution stains hands, clothing, etc., black so be careful. Discard the test sample; do not store it.

Musicians, Faversham Although even quite brief washing is sufficient, trade-processed chromogenic films are sometimes not washed at all but merely stabilised: this is Kodak Portra 400CN. We now prefer to process our own chromogenic films, or at least, to have them returned uncut so we can wash them ourselves if we have them trade processed. Frances used a Voigtlnder Bessa-T with 50/1.5 Nokton and 2x yellow filter from B+W.the bottom lineFilm developing isn't difficult, and (as so often in photography) there are many paths that lead to the same end. There is also a lot of alchemy in it. If you particularly admire a photographer's prints, by all means try the same film, developer and development regime (and exposure technique and paper and paper developer...) but be prepared for the possibility that it may not work for you. Best of all, try to get the technical information for a number of photographers whose prints you admire. In all probability you will find such a wild variety of films, developers and development regimes that you will have several to try if the first one doesn't suit you. Go to the list of modules or go to the home pageor support the site with a small donation.Top of Form

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