Dominic Case

Because film stock is designed to be very sensitive to light, it tends to be a little sensitive to other forms of energy as well. These include radiant heat, cosmic radiation, x-rays, etc. Silver halide crystals also have a greater tendency to spontaneously become "exposed" at higher temperatures. What happens is that photons of energy collide with silver halide crystals in the emulsion and knock an electron out of place in the crystal, forming a non-ionised atom of silver. Crystals with several such atoms of silver will be converted entirely to silver in the developent process (forming an image): those without them won't be. If you wait around for too long after exposure, a few of those non-ionised atoms of silver will settle back into the regular crystal structure, and the effect of the exposure will be "forgotten". This is latent image fade. As with exposure and heat fogging, higher temperatures will make this happen faster. As it happens, latent image fade starts off fiercely, then slows down. However much of the latent image is lost in the first day, it will take two days for the same amount again, then four days etc. So in practive, laent image fade isn't a serious problem. Better to keep exposed fill cool if it's goijng to be weeks before processing - but don't worry about a couple of days - and if you've had the roll for weeks and weeks before processing, still don't worry: at worst it'll probably turn out as if it had been half a stop under-exposed. Almost always it is easily corrected.

Are you suggesting using a water-wet cloth to clean film? This will certainly soften the emulsion, but almost certainly allow more stuff to stick to it - and if you wipe it with a cloth you'll damage the emulsion. NOT RECOMMENDED! Good quality cotton buds with something like isopropyl alcohol are the best way to get individual specks of dirt off. If they are really cured in, then methylated spirits can help - the fast evaporation causes a little water to condense from the atmosphere, and this very gently softens the emulsion. In large-scale continuous processing machines, the film passes through a series of water-wash tanks, which are more effective than sprays at removing processing chemicals from deep within the emulsion. The final wash uses clean, finely-filtered water, which is then passed back to the earlier tanks. This is called counter-current washing, and uses far less water than either fresh water throughout, or spray washing (as well as being more effective). Environmental considerations such as minimising water usage are critical to modern lab processing. Jets and squeegees ensure that nothing sticks to the emulsion. If any dirt does get onto the film emulsion, it is usually in the drying cabinet - so this also has filtered heated air passed through it. In a home-processing environment, I'd suggest that clean, dust-free drying conditions are at least as critical as any hosing down of the film.

This page has been around for about ten years! Yes, it's a joke. When I first saw it, I forwarded the link to a cinematographer's forum (it was before this one existed I think) and also to a telecine forum. In general, cinematographers either got the joke, or reacted in horror. Most of the telecine folk rushed to ask where they could get the technology. OMG! :o The worrying news is that exactly this process is now genuinely available - at least for still images. Look at this. http://www.seamcarving.com/

Not so fast. For many years Kodak supplied Ektachrome (ME4, and, I think, the later VNF1-process emulsions) slit as 35mm, just to the military. This was not available for public or commercial use. With regard to the original question: please stop and think what you are saying. You are looking at material that was shot 40 years ago, was probably transferred to video at the time or not much later, and may well have been duplicated through analogue video processes any number of times. Yet you compare it with original material from a modern digital camera. Is this reasonable? Alternatively, if the transfer you are looking at is new, and the program makers have gone back to the original footage, then you are looking at film that was processed 40 years ago. Maybe it's faded in the intervening years: yet you don't question the military's archiving practices. If you want to make a simplistic comparison between film and video in those terms, then I suggest you compare film shot in the 60's with video shot at the time. I don't think you will find much ENG-type material from the 60s, or indeed many video cameras that were capable of operating out in the field let alone in the air. That is one of the reasons they used film! You might also compare film shot then with film shot now. American spelling is the result of Noah Webster's rather confused scholarship and political idealism. Wanting to set the American colonies apart from what he regarded as the interfering aristocratic traditions of British spelling, he believed (correctly) that language should be under the control of the people (this was around the time of the French Revolution) but then sought to control spelling himself through his publications. The idea that spelling and phonology should match perfectly also seems like a quaint idea from the height of the Age of Reason - which in the "old world" was already getting a little out of date by the time Webster's spelling books came out.

The Kodak books that Michelle recommends are excellent. For a more practically oriented look at film, processing and printing, my own book Film Technology in Post Production (Focal Press, 2nd edition) should give you a lot of information. It's available from Focal (Elsevier) as a hard copy or as a downloadable e-book. From a cameraperson's perspective, get Paul Wheeler's Practical Cinematography. It's in its 2nd edition, but I suspect if you can find a first edition it might be a little more oriented towards film as distinct from digital. Good luck.

Consensus here seems to be that Tiffens are a little brown. Or green. Or that you can't spot the difference. Or that you can, (but not enough to specify what the difference is?). Even if you don't see a difference by eye, a filter may be off-balance at the UV or IR end of the spectrum. Carbon filters are much more uniform across the entire spectrum than dye filters. It is also possible that some dye filters will fade over time, so while a new one could be neutral, older ones could pick up a colour bias. In practice, a slight colour shift can usually be corrected. Some lenses have a slight colour shift too.

One of the greatest advantages of shooting negative is its latitude, or exposure range. You capture a much wider range of tones, which you can then work with on telecine. If you shoot reversal you are throwing that advantage away. So far as looking at the film itself (for quality issues) is concerned, why can't you look at negative? If a few more telecine operators bothered to look at the actual negative itself, we'd have far fewer anquished postings here and elsewhere about mysterious scratches or flashes or jittery images. In the old days when it was used for newsgathering and current affairs, the point was that editors could cut the original material without waiting for a print - and telecines were better configured for transferring a projectable amage than a negative. But that was then - this is now. Today I can't see any good reason for shooting reversal for telecine.

I agree completely with Phil. (I just had to take the opportunity to say that - it doesn't happen very often ;) )

Well no-one ever said it was eay running a lab well. Every lab I've worked in has had a chemical analysis department, which takes samples and analyses the solutions on a daily basis. Specific Gravity (yes with a hydrometer) and pH are among the first and easiest tests: others involve quite complex procedures with pipettes, burettes, separating flasks and the like. Replenisher flows are calibrated regularly (that is the sort of thing that Kodak Imagecare requires), and the temeperature controllers in thge machine are cross-calibrated against a standard thermometer. Correct, although they are much more uniform than they used to be. But that's not an issue anyway. Labs run regular sensitometric strips on a standardised emulsion, not on the batch or emulsion type(s) that they are processing on the day. The process is maintained as a standard against a standard emulsion with known aim points: if a different batch produces different results that is entirely a matter for the manufacturer, not the lab. You don't vary a process to chase after emulsion differences. If things are done carefully and consistently and accurately, there isn't often any need for a replenisher correction, or temperture or anything. If a correction is needed, it's a bit like steering a car (or more like a boat really) - you apply a correction, and see how it goes: if it brings you back on course that's good - if you need a little more, you apply a little more - and so on. It's a skill to get it right.

You've cearly illustrated the difficulty of diagnosing this type of problem here - simple comparison tests are rarely conclusive. However, what you need to do if you haven't already, is shoot a comparison test on your camera, and on another similar one. A double-run registration chart test would be ideal. And you should use the same batch of stock that you've been using (if any is left) in both cameras. Be sure to get them processed together (excessive temperature in the drying cabinet can cause warping of the film, which could lead to the problem you describe - and that could affect one type of emulsion more than another, as they have slightly different water-loads, so dry at different rates). Simon's theory is also relevant: if the camera uses edge-guides, then any sort of pin-registering in the telecine will show up any weave in the edge slitting. I haven't heard the term sabrage - thank you Simon, for that new piece of information.

There you go again! Australia? New Zealand? Or was it South Africa? Somewhere down there, they all seem the same. Perhaps Austria. You Canadians are all as bad as each other :P (Apologies to those north of the Great Lakes, I'm sure you'll understand ;) ) Oh, btw Farscape was made in Australia.

Kodak usually spends several days getting its test strip processor up to exact standards before processing the reference samples - and usually gets pretty close to "ideal". Though what makes "ideal" is hard to say: emulsions do vary very slightly over time, so even if a result is different from the same batch processed three months ago, it might not be a processing variation. However, it's easy to be accurate and consistent within a quarter of a stop or even a sixth of a stop (which is a negative density variation of about 0.03 in the mid-scale). An increasing number of labs are taking on the Kodak Imagecare system, which requires a very high level of quality control, regular testing and record-keeping, routine maintenance, etc. The labs are inspected by Kodak every six months, and their sensitometric records for the entire period since the last visit are examined. There are labs all around the world with Imagecare certification (including, in reference to another thread, Indai and Mexico, though not many in the US).

Karl, I know ( I hope ) you are just being provocative. But your statement actually says very little. All you are saying is that the best processing lab in the world today is in America. Out of all the - what is it, a couple of dozen - labs in the US, you are saying that one is better than anywhere else - in your experience. It seems you are taking Mexico and India as your sample of the rest of the world. No-one can escape a biassed view in this, but in the 30 years I have worked in processing labs, mostly in Australia, I've seen very good and very bad work out of labs here, and I've seen some truly embarrassingly bad work out of US labs - as well as very good work. Well of course it is if that is what you are brought up on. Personally I rarely watch an American film: if you want me to generalise, I think the French do the best cinema at the moment. US stuff is technically dazzling, but that's a lot to do with the amount of money that is thrown at it. As for music, I don't listen to much written in the last 100 years, though Gustav Mahler did turn out a couple of good pieces while he was in New York :P. Television - American the best? How much non-US TV do you get to see in the US? Here in Australia, at least half our TV is non-Australian, which means we can make a fair comparison - and personally, I'd rate British TV well above American TV. But those things all depend on personal taste.

Borax will soften the remjet coating, but as the remjet is actually fine particles of carbon, it doesn't actually dissolve in any solution: it needs to be physically removed. In a professional processing machine it is removed by accurately aimed jets of water which spray it off without it getting onto the other (emulsion) side of the film. In fact, getting the remjet off one side isn't so hard - preventing it from getting onto the other side is the tough part of the job.

Then they were very lucky, and so were their other customers. The difficult thing with Remjet is not getting it off the film, it is getting it out of the machine. ECN2 processors have quite elaborate directional sprays to wash it off and flush it completely away before the film gets immersed in developer, where any unremoved remjet would drift off and around in the solution until it was removed by filters, or stuck to a passing emulsion surface (more film, that is).

OK. Several points. Atlab Sydney is now Deluxe Sydney - same contact details but website is now www.bydeluxe.com Mail or Express Post out of Aust will cost anything between around AUD20 and AUD55 depending on how quickly you want it. AUD20 is for registered post, AUD55 for Express Post. Ordinary Airmail is AUD15. You can check it out on the Australia Post website. Beware of shipping UNprocessed film by ordinary mail services. Think X-rays. Think again. Not sure what the lab now charges (as I'm no longer there), but from memory you might expect around $12-15 (AUD - that's more like US$20) for process only: but the gotcha is a minimum bill amount which might be around $50. So it's not worth sending one cassette, you'd want to shoot several. Another important practical detail - when neg is processed in a continuous processor, each roll is joined to the next in an overlapping join with a couple of inches of film overlapping. So, also allowing for handling at each end, it's a good idea to wind on about 5 exposures before you start the roll, and only shoot until you are 5 frames from the end of the roll. For a standard 5 foot exposure length (normally 36 still frames) that gives you around 25 or 26 frames.

Can it be true? Wow, the prices are certainly coming down. In the early days it was priced in dollars per frame.

Really, the cost of the camera is only the beginning. You can pick up a 35mm movie camera of sorts (probably a Konvas) for whatever you want to pay - but any change you get from $4,000 will very soon disappear on the cost of film stock, processing and transfer. You can pick up a DVX100 for half that, spend not very much at all on feeding it. Then you can get a top featured 35mm SLR for under $100 (they really are going for a song now) and feed it with 35mm neg for ever and a day, while you are working out how to shoot on film. Meanwhile, very few festivals care what you shoot your film on. Some still require a 35mm print for the screening, others are happy with a range of digital (or even tape) formats, from DCI approved D-cinema specs down to DVD. Many low-budget film makers are locked out of the 35mm festivals as the cost of tranferring their production to film (or back to film) and making a print turns out to be as great as the cost of making the film in the first place. If you shoot on film, it is possible to finish the production entirely on film, and not have a digital copy at all, except for the edit. But I somehow suspect that you won't be following that path.

Hang on, who's being hard to contact here? Anyway, like others, I counted 6 email addresses on the contact page on their website.

Happy to be of some assistance.

Simon, I promise I'm not deliberately picking arguments with your posts. But I wonder if it is wise for someone who suggests that they have cameras in theatres . . .is really ready for the large financial drain that shooting 35mm entails. And Michael, there is nothing in film making that fits the description " all you need do is . . . .". I reckon that people would choose to shoot on film because they know what a difference it makes. If you know as little as Michael admits to (which is fine, gotta start somewhere) I think he should keep the digital option open. A lot less learning to start with. But David is right - more information please. What do you want to do?

I'd certainly agree with that. The number of subtly different things to measure, and the number of similar-sounding units to measure each one, ensures confusion. I always reach for my notes before embarking on any discussion. Briefly, the standard candle or CANDELA measures the total light emitted by a source. It is different from the FOOT CANDLE which is a unit of ILLUMINATION. In metric, it's a metre candle, or lux. It's the illumination of a surface a foot away from a light source of one candela. This is the one that depends on distance - move further away from the source, the candelas of the source remain the same but the foot candles of the surface are less. Foot candles are what you measure with an incident light meter. (BTW, illumination is also measured in lumens per square foot (or metre). LUMINANCE measures the brightness of a surface. It depends on the illumination (foot candles) and on the reflectance of the surface. Measured in FOOT LAMBERTS, but also candelas per square metre, or nits. That is what a spot meter will give you. So in effect, you can use candelas to measure the lighting ratio of your scene (key to fill etc) but if you are interested in the brightness ratio of the scene, you'll need a spotmeter and foot lamberts. This will tell you how many stops down the black curtains are, compared with the white lace ones for example.

I don't imagine many people regret the passing of Letraset, though in its time it was very good. Just tedious. And unless you were a high volume user, you'd always run out of some letters really quickly. There was a transitional stage though when titles were created on a computer and then printed out onto cards and photographed on a rostrum camera. I have in my little collection of curios, a set of Japanes subtitles for a feature film, printed onto a stack of cards, about postcard sized. Black letters on white, which isn't ideal, but was probably quicker to print. They would date to the late 1990s. They were intended to be photographed on a rostrum camera on hi-con stock then printed back to make a full-length master subtitle roll.

Paul wrote: Along with others in this strand (Dirk & Brian) I am convinced that any special technique such as flashing, forcing, bleach-bypassing etc, should be done on the basis of testing. While it may be possible to shoot a grey card at two stops under and get a precise and predictable grey density, it's more important to see what effect that density has on your image. The visual effect will depend very strongly on what the image is like. Doing it purely by numbers is like advising someone that the negative density of an image will be about 0.18 less if they underexpose by one stop. Yes, but that tells you nothing about what the image will look like - in the shadows, in the saturated colours and so on. So please ignore the mass of numbers and calculations in my previous post, unless you really want to work with sensitometry. I just wanted to correct an earlier post. So Paul, please save the virgins for a more deserving cause - they are a precious commodity :) Dirk wrote: Good advice throughout. By the way, if you don't have a 18% grey card, you could use a white one - so long as it is perfectly matt. You'd need about 2 or 2 1/2 stops less than the grey card, assuming a reflectance of 90% to 95%. It certainly is, and that is why a test is some important. A mistake in the relatively unfamiliar flashing operation will stuff up your shoot. Finally, Simon correctly points out: Quite simply, look at the curves on the manufacturer's website - the D-min is the lowest value of density - at the left hand end of the characteristic curve - or ask the lab to measure it on the stock that you are using. Dmin values do vary from stock type to stock type but typically you will get 0.17 to 0.22 Red, 0.55 to 0.65 Green, 0.90 to 1.10 Blue.

I'm sorry to be blunt and direct, but this information is (i) confusing; (ii) unnecessary to answer the question; and (iii) completely wrong. In fact it is SO wrong, I feel the need to correct it. The concept of density was introduced (well over a centory) ago as it was useful to describe the behaviour of film emulsions simply. It is also a simple unit to work with: densities can simply be added, whereas tranparencies (or transmittances)have to be multiplied. Opacities are even harder. Simon, what is the combined effect of a 68.4% opacity filter laid over a 20.6% opacity filter? Quickly now! Pass? OK what is the combined effect of a 0.50 density filter and a 0.10 density filter? Answer, 0.60 density. As far as Simon's example calculation is concerned, yes it's true that the opacity of a 0.50 filter is 3.3 times that of a 0.10 filter (assuming that the figures of 68.4% and 20.6% opacity are correct. )That doesn't tell us much about their relative densities. In fact, if you insist on using the linear terms rather than the simpler log terms, you need to compare the transmittancies: 31.6% and 79.4%, whch have a ratio of about 2.5:1. A ratio of 2:1 would be a difference of one stop. 2.5:1 is about a stop and a third, which you would only know if you know your log tables. Much easier to subtract 0.10 from 0.50 and know that the difference, 0.40 is about a stop and a third (0.30 is one stop). But this is still only the difference in densities. Not only are you comparing the wrong numbers, you are overlooking the factor of the gamma of the negative stock - which Brian brings in to the action, straightforwardly and simply. Good information on this site may be useful to one or to many people. Bad information is worse than no information. If you don't know the difference, please don't post.