C-41 homebrew - Really doable? Or Purchasing problems

OK, first post here. Hi, all.

My intent is to mix my own C-41, in particular the developer. While I am not a chemist, I am capable of following instructions and reading up on backgrounds, including MSDS sheets.

Disclaimer - I have no intent of proclaiming self mixing as the only way to go, saying its better or worse than pre mixed stuff or do a cost analysis. I only wish to mix my own out of curiosity and to gain a control by knowing what is in my developer.

The last few weeks I have spent a lot of time surfing for recipes, formulas, etc. through apug.org, www.largeformatphotography.info, photo.net and lots of other sites. Even some patent sites the last few days e.g. European patent office: http://v3.espacenet.com/textdes?DB=EPODOC&IDX=US5827635&F=0&QPN=US5827635

I came up with only two leaving aside the ones in various patents, like the one in the link above. These are also mentioned in a recent post here by srs5694: (there was a url link here which no longer exists) Well done!

What I did find is a lot of people saying 'yep, can be done' mostly referring to the info given here: http://www.bonavolta.ch/hobby/en/photo/c41_ra4_chemicals.htm.

I have now contacted several dealers first in the UK (where I live) then USA and the result is: I cannot get the core chemicals.

e.g. http://www.process-supplies.co.uk/ and http://www.silverprint.co.uk/
don't do Hydroxylamine Sulfate and Ferric Ammonium EDTA. Never mind Formaldehyde or Sulphuric Acid. General argumentation: EU laws, health and safety regulations. A third UK supplier Rayco Chemicals, I just talked to on the phone. The very kind new owner has bought the company in Feb 2005. There is no website yet. The gist: He is unlikely to purchase new stock of colour chemistry (e.g. CD3, CD4) - there is no market. If there is old stock, that will be sold of course. All dealers mentioned regulations regarding storage and handling as, by now, major hurdles.

Attempting to contact three US suppliers, I only got a response from The Formulary http://www.photoformulary.com/ They cannot send CD-4 and Hydroxylamine Sulfate to the UK - hazardous chemistry.

Is there anybody out there that still mixes chemistry and has actually purchased some in the, say, recent months? In particular in the UK/Europe

Has self mixing C-41 (probably E6 as well) been killed of by regulations on the one hand and quickly dropping demand on the other?

I'd be happy to hear your thoughts - expecially those of any home brewers.

Ta, Martin

I only mix the C-41 developer and stabilzer myself. All the chemicals are [or at least at the time] could be easily gotten from

Dead Link Removed

I don't know if they ship to the UK but if they do the cost of the shipping would hurt.

I can't see any reason to mix anything but the developer and maybe the stabilizer. I know the bleach isn't cheap but it keeps fairly well. The fixer shouldn't be an issue for you to pickup. It also keeps fairly well. If you can find a supplier selling to mini-labs etc then see about buying big [5 litre or maybe 2litre no smaller] jugs of bleach and fix.

If you really want to mix your own bleach and fix then skip the blix. Use the alternative bleach and fix.

The demand for CD-4/CD-3 isn't set by the home market it's by people like Kodak,fuji etc mixing huge amounts of this stuff.

Hi Nick,

I'll check out JD. But agree the shipping costs are usually painful. Someone wanted US$10 to send a step tablet.

I agree, that the only real value is in mixing the developer. The rest does not have a major impact on image formation in comparison, so I am happy to go with of-the-shelf branded stuff. Though I will also check out the 'alternatives' regarding obtainability.

Shipment by air has more restrictions than shipment by ground. This would be a problem when ordering from the US. You might instead try locations in Europe for chemicals, I know that there are people in Germany who make there own processing solutions.

Hydroxylamine is a known carcinogen and probably the hardest of the ingredients to obtain. CD-4 is a skin irritant and I wouldn't eat it but not all that dangerous. Check with a university to obtain a small amount of formaldehyde since it is used to preserve specimens. The ferric-EDTA used in the bleach should be available as it is sold as a source of iron for house and garden plants. However, I find it too be rather slow in its bleaching action and prefer to use the E-6 ferricyanide bleach instead. Everything else is pretty much the same as for B&W processing.

Keep trying and don't give up just yet. Contact some camera clubs and see if they have sources for photochemicals in Britain. Thankfully the US and Canada have not yet reached the same level of paranoia that the UK apparantly has.

In order to reproduce your results from hand mixes of C41 or other color developers, you must be within about +/- 0.1 pH units at 20 deg C with a calibrated pH meter.

In addition, you must be within +/- 0.1 grams in weight of some of the components, and in the case of one ingredient, you must be within about +/- 1 mg (IIRC - I would have to go look it up).

This is mainly for color balance, edge effects and grain as the layers interact with each other and the interaction must be controlled precisely.

This is why I feel it undesirable to mix color chemistry, let alone the fact that most published formulas are only close approximations to the real thing and therefore while they may work with one film, they may not work with others. In addition, testing the results in image structure and color are quite difficult and usually people only eyeball their results. They usually make no direct comparison with the 'real thing'.

PE

Gerald: the paranoia - I'd agree on that one. Now, I wonder how unhealthy tap water is, taking into account old piping systems... OK, thanks for the encouraging words. I'll keep hunting.

PE: Thanks for the details, I had read similar posts of your's already. It would be great if you could specify which components need the accuracy, in particular which one needs the 1mg accuracy. I trust I can achive that accuracy in any case, but don't want to put in an effort where not needed - avoiding paranoia.

While in general I would agree that accuracy is needed, I should state again that my main intention for mixing chemistry is curiosity as well as taking personal control and not a hypothetical _technical_ ideal. And in that sense I am perfectly happy to 'eyeball' my results but not only with a quick glance also with a magnifier, i.e. on the micro level.

Whether, say in a portrait, the skin is a bit more warmer (yellow) or cooler (blue/olive cast) is not only a technical question but also an aesthetic one. Grainy (B&W and C) shots can look great or ugly. Look at lots of the fashion/lifestyle stuff - how off are colours there. Product photography uses lots of subtle lighting to create well pleasing images. Compare an image of a Big Brand Burger to the real thing.

So, for me, if the results of any homebrew are optically pleasing on macro and micro level, I am happy. If not, I'll move on. Experience gained, lots learned. Just like I learned that most labs with professional control just don't give good results. But on them I have no influence. At home I have an influence. Even if not technically perfect, that is the kind of control I like to have.

Guess I am saying the end justifies the means as well that I'm in it for the journey. But that only has validity for myself

Critical items are: The pH, iodide, bromide, color developing agent and sulfite. These are in order of importance high to low. The first 3 are critical.

PE

Thanks for that. Would you take into consideration the water used for mixing? I.e. mineral content reflected in ph and oxygen content? I know our water here is really waky and surely will trip any mixture by more than 0.1. Sure, with a home brew I'd measure the grand total after mixing and then correct. But most 'consumer' C-41 kits never make a mention of it, never mind reminding to check/control the ph. Would that be more important in a home brew?

As you mention that one chemical needs 1mg accuracy, I assume you refer to Iodine. The recipe I am looking at does not mention iodine at all only potassium iodide and that is in the blix. Do you mean that? It is used in a fairly small amount of 1.0g so 1mg would be 0.1% variation, not a big one, but alas, maybe relevant. Of course, you might have another recipe in mind actually using iodine. Or maybe the amount given (1g) is wrong anyhow.

It would be great if you could share any more accurate information you might have, or at least point me to it, I could use to possibly use, to get better 'mixtures'. Unfortunately I have not found any information in the last weeks giving weights as, say 1.032g i.e. accurate to 1mg. The best I have seen is weights given to 0.1g implicating an accuracy of 100mg

For that matter, it would be great to know, possibly before delving to deeply into my adventures or to better guide them, would deviations can I realistically expect, if say, the ph is of by 0.5 or even 1? Similarly with the (I assume) potassium iodide, if I am off by 0.1g?

Maybe I am missing the obvious, but something I modify with 5 or 10cc when printing seems trivial to worry about. The (in-)accuracy of the aperture ring markings on the lenses, temperature (!) dependency of my spotmeter (never mind the inbuilt on) as well as their accuracy due to what-not and colour shift's due to daytime, clouds, humidity, etc. probably produce way more variance anyhow.

But as said, it would be really great if you could give me some hints where I could find the information you base your knowledge on so I can do further reading myself. Possibly even a better C-41 recipe if you can spare one

BTW don't get the idea I see self mixing as _the_ way to go. It's one of many ways. I like diversity and exploring.

Things like potassium iodide, that are used in very small amounts, are best made up as percentage solutions. One gram of potassium iodide in 1 liter of water would make a 0.1% solution. A typical E-6 developer would call for 30 ml of this solution in the second developer.

On reading my last post I find that I left out that a formula calling for 0.3 g (possibly hard to weigh out accurately) of potassium iodide would use 30 ml of a 0.1% solution.

It is indeed potassium iodide, and therefore if it is left out of the formula you have, consider the formula to be defective or inaccurate as KI is an essential ingredient for control of image quality.

The limits call for a very tiny deviation in iodide, but I would have to look up the information.

Water quality does impact on process quality. The commercial preparations contain extra ingredients to minimize the effects of municipal water supplies, and kits in Europe differ from their counterparts in the US for this reason.

As a general rule, C41 developer contains Quadrofos to control water quality problems related to calcium. It may also contain Disodium EDTA as needed to remove other metal salts such as iron and the like. If you mix with distilled water, this is not usually a problem, depending on the quality of the distilled water, of course.

PE

Thanks Gerald. I had read the approach of the percentage solution somewhere here before (possibly in a post by you) - that's why I was confident to handle small amounts accurately on a scale doing 10mg accuracy You've just saved me wringing my brain to get the right numbers together...

PE - thanks for the additional info too! So there is obviously a need for additional components. I'll read up on them. It would still be great if you could give me a hint as to which direction any deviations would take should the ph or potassium iodide be of - at least then I could do a better diagnostic should I not get the result I am hoping for.

If pH goes up, contrast will go up and interlayer interimage as a function of diffusion effects (depth or position within the coating) will generally decrease depending on the magnitude of the error. But this depends on whether the pH error is in the quantity of sodium carbonate or of sodium hydroxide. Both increase pH, but only carbonate increases buffer capacity (see my other posts on the thread regarding semi-stand development for more information). The error may be small.

Decreased pH will decrease contrast and increase interimage as a funtion of 'depth' into the coating. Both of these will affect color reproduction and the red speed relative to green and blue.

Iodide changes are more subtle. Iodide is released along with bromide from the developing grain and acts as a powerful restrainer. If iodide ion is absent from the developer, then edge effects tend to be enhanced, and you can get a 'halo' effect around dark objects. This is hard to see unless you look at magnified images. Too much iodide can lower speed and sharpness.

Bromide variations are similar to iodide variations in effect, but less powerful. Both can lead to 'drag' if the wrong levels and wrong agitation are used. Low levels of either tend to exaggerate agitation problems and increase drag effects. Depending on the film type, you could get iodide drag. High speed films are generally higher in silver and iodide content so it may vary from film to film.

The developer and film are adjusted against each other to maintain the correct results in the presence of an exact ratio of these two halides.

At the least you might just see fair or even good color, but the neutrals might be off, or the reverse might be true, with good neutrals and offish colors. More subtly, you might see less sharpness or higher grain.

This all begs the issue of what happens if you use a blix instead of a bleach fix. Film blixes are hard to formulate, and retained silver is a common problem with them leading to higher contrast and desaturated colors. Sometimes, cyan leuco dye can form if there are errors in the blix formula, especially pH.

PE

Please would you quote what book you've just read this in !

Ian

Photo Engineer said:

If pH goes up, contrast will go up and interlayer interimage as a function of diffusion effects (depth or position within the coating) will generally decrease depending on the magnitude of the error. But this depends on whether the pH error is in the quantity of sodium carbonate or of sodium hydroxide. Both increase pH, but only carbonate increases buffer capacity (see my other posts on the thread regarding semi-stand development for more information). The error may be small.

Decreased pH will decrease contrast and increase interimage as a funtion of 'depth' into the coating. Both of these will affect color reproduction and the red speed relative to green and blue.

Iodide changes are more subtle. Iodide is released along with bromide from the developing grain and acts as a powerful restrainer. If iodide ion is absent from the developer, then edge effects tend to be enhanced, and you can get a 'halo' effect around dark objects. This is hard to see unless you look at magnified images. Too much iodide can lower speed and sharpness.

Bromide variations are similar to iodide variations in effect, but less powerful. Both can lead to 'drag' if the wrong levels and wrong agitation are used. Low levels of either tend to exaggerate agitation problems and increase drag effects. Depending on the film type, you could get iodide drag. High speed films are generally higher in silver and iodide content so it may vary from film to film.

The developer and film are adjusted against each other to maintain the correct results in the presence of an exact ratio of these two halides.

At the least you might just see fair or even good color, but the neutrals might be off, or the reverse might be true, with good neutrals and offish colors. More subtly, you might see less sharpness or higher grain.

This all begs the issue of what happens if you use a blix instead of a bleach fix. Film blixes are hard to formulate, and retained silver is a common problem with them leading to higher contrast and desaturated colors. Sometimes, cyan leuco dye can form if there are errors in the blix formula, especially pH.

PE

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Ian, my associates and I wrote much of this in technical reports during our tenure at Eastman Kodak. I have done extensive experimental work in this field. So, if you will, I quote myself and my peers using unpublished work. However, I have revealed nothing proprietary or counter intuitive.

In addition though, the pH tolerance is given in some patents pertaining to C41 and E6 both but all of the detailed formulas with detailed information were available in our little black book which I turned in when I retired. Naturally, quoting from that would reveal proprietary information, even if I could remember all of those formulas and other information.

Having worked extensively on the C41 process and film family, I feel confident that the information is accurate and informed. In any event, the 'bromide drag' effect is hardly new, nor is the effect of pH on development and contrast. The logical extension of drag to iodide and other inhibitors such as DIR fragments is hardly new or unexpected and the extension of these to image structure is obvious. Diffusion effects are discussed extensively in the literature as well.

You may wish to look up articles by Rodgers and Kapecki on the structure of color negative films for more detailed information on this type of effect. Kinetics is discussed well in Mees and James, and diffusion is discussed by Liang and Willis among others in their publications. Kriss discusses edge effects and micro contrast in his publications.

I hope that this satisfies you.

PE

PE: Thank you for detailed answer to my inquiry. Reading that and your reply to Ian, you appear to have worked in very great detail depth, or rather, you particular activities with Kodak that made you pay attention to very fine details. Realizing that you are likely to be under constraints at to what you can or cannot say your input is all the more appreciated. Having spend a good number of years in IT, I also have comparable constraints as would anyone working in professional fields, so I understand the issue.

In your reply to me you mention: "If iodide ion is absent from the developer..." Now the thing is, in the formula I was and still am referencing, there is no iodide in the developer. So I suppose your reply was more in general terms rather than in direct connection to my original post. Nonetheless helpful information, though a more specific answer would be appreciated. I would assume then as you state that, potassium iodide would be a crucial component in developer. Please correct me if I am wrong, or you are thinking of a different iodine salt because you simply abreviate to iodine.

As you might well understand, simply hearing something is wrong, for a non-expert or "informed-beginner" is of little constructive value. I am always eager to go forward and correct, within reason, what someone terms as wrong or inappropriate. I am also thinking of future readers over the years who maybe looking at this thread eager to find contructive information.

With the understanding that you are contrained in what you can say and that it is my intention to find out more details about self mixing C-41 chemistry, I would very much appreciate more specific information. Specific chemistries and amounts you would feel are needed to compose process component. I am sure, with your background you can well abstract from specific rights constraints.

Realizing your in depth work experience, I do understand your focus on extremely high precision. When you state "developer and film are adjusted against each other", I am sure the major players all do such things. Yet this perfection breaks down when you process brand X with brand Y chemistry. A common real life situation I am sure. The result may still be good or even great. I would tend to think the judgement whether a result is acceptable or not is a very flexible concept and depends on context. Architectural photography for a mural is not the same as an image landing on a webpage at 400x300pixel.

If you will excuse my rambling, I would certainly agree with you that there are places for high technical accuracy. For me technical perfection and aestetics, while not independent, can be quite independent. Bluntly, a technically perfect image can be just plain boring or awful. And whatever variants of that sentence can be formed. And for those, like me, who do want to improve their results, finding contructive input on how to so on a technical level is most welcome!

Martin, you are certainly correct about the degree of flexibility in the developers and the ability to tolerate all mixes of films with some degree of average good quality.

But then, the other side of the argument is that all films made for C41 are tested for the real C41 developer formula, and that formula tends to mitigate unwarranted deviations that might be present in other developers.

For example, mixing a 5% iodide high speed film with a 1% iodide low speed film in an iodide free developer may result in different side by side 'contamination' effects between films that the presence of iodide in the developer is intended to damp out. You see, each halide can be considered to be part of a feed back loop or dampener for excesses in reaction.

So, the correct C41 developer contains KI at 2.0 mg/liter and that is a VERY precise amount. It acts as a 'dampener'. The pH is 10.48.

It contains polyvinly pyrrolidone and diethylene triamine as well for other effects such as neutralizing problems that arise from using municipal water supplies. I mentioned this above.

I admit that some of these deviations in response might be acceptable, but even in a hobby, the cost of film and chemicals is not insignificant, and the time to take the pictures is not worthless either, let alone those pictures that can never be reshot. So, although I have the formulas and chemistry, and I think mixing the chemistry is elegant, I use prepackaged Kodak chemistry. Fuji-Hunt is just as good, but harder to get here in Rochester. (I wonder why??)

Anyhow, having found one error in a formula, or two, or three, do you wonder what else lurks there? I have found, in practice, that the real formula 'creeps' even from Fuji-Hunt and Kodak, due to product 'creep' and the introduction of new technology. For example, at one time color paper used Calgon and hydroxylamine in the developer, but Calgon changed their product formula so Kodak switched to Quadrofos, and then they found that Diethyl hydroxyl amine oxalate was easier to handle so they switched to that. This resulted in a tiny correction in the paper formula and the developer formula that was gradually introduced so that no upset was seen by the customers.

In particular, IIRC, it was introduced regionally, and major customers were informed of the change. Tech Reps stayed on top of the changeover to insure quality and uniformity. This has happened several times over the years.

PE

PE: after a couple of days of C-41 processing (ready kit) a couple of thoughts as not to drift OT too much. First of all thanks for the hints regarding Iodide salts which I will happily take into consideration. By now I even translate the use of Iodine to the more accurate Potassium Iodide. Your question whether finding a fault in a formula wouldn't put me off it. Yes and no.

Let me explain. You refer to 'the' C-41 formula. While I am happy to believe that there might be such a thing (or not), it certainly is not available to myself. The few patents I looked at also don't give this information away. Why should they? As you explain yourself, the real life C-41's (plural) have probably mutated a fair amount. This can be due to product development as you state or difference between companies, environmental protection rules, etc. After just purchasing a bottle of Kodak Stabilizer & Replenisher III with formaldehyde, I read its replaced by a formaldehyde free one. I'm sure the store (Silverprint, London) is happy to be rid of the old stuff.

Having just used the Fotospeed PK-C41 kit I have also found out how unstandard things can be. I will detail my results in a thread yet to come but the short of it is a dilution of 1+3 rather than 1+2 and a reduction in dev time by 20% gave near correct results. Option 1 (negative): Fotospeed does not know how to mix C-41. Option 2 (more positive): there is a clear reasoning for their formulation behind this but not visible to me and the world. A possible conclusion could be to a) stick only with brand name kits. b) from now on only use Fotospeed as I have now figured out how it works.

Now looping back to my reasoning why self mixing and clarification of the formulae is something I like. In a word: control. Not a single manufacturer will tell me, brand or non-brand, what's in the package. I am waiting for the day when chemistry dealers apply the (software) open source concept and start offering premixed kits _and_ declare precisely what's in them. jdphotochem.com has such kits, but I have not seen content declarations. Besides, they still have not replied to email and not answered the phone either. So yes, published homebrew formulas may be deviant from a possibly obsolete formula tucked away in some safe. And they may need modification to improve performance, but they may be just as deviant as real life preparations. The difference is that the formula is something I can modify, but not so with prepacked stuff. If something goes wrong, I am completely in the dark. I simply cannot tell how much, if any, Potassium Iodide is in Brand X developer. I don't even know if they are still using CD-4 or one of its hundreds of variants as Kodak proclaims in a patent.

The advantage I see with using eg Kodak over Photospeed is not my belief that the chemistry is inherently better, I don't know that and I do not trust sales speak, but rather that their documentation is much better. This gives me detailed info which I appreciate.

So, yes, it worries me to find a fault, but no, not to much. I find enough faults in pre-packaged stuff as well. Self built computers and Big Brand ones both have problems as well. I have always self built.

That is the reason why input by people like yourself who do have more insight into the chemistry are valuable in this forum. Giving info like you did about the Potassium Iodide together with an appropriate reasoning gives understanding. With that I can then decide whether to modify my approach or not. I just prefer informed decisions rather than trusting 'we are so good and the best' talk.

In that sense, if you could look at this formula (source early in this thread) and a) make suggestions as what to add, remove or modify b) and, this is in line with my original intent of this thread, because Hydroxylamine Sulfate is considered too unhealthy and therefore difficult to get, how that can be substituted. I guess a first addition would be 1.0g Potassium Iodide.

Thanks for any help!

Water (Room Temp) 800.0ml
Potassium Carbonate 32.0g
Sodium Sulfite 3.5g
Potassium Bromide 1.5g
Hydroxylamine Sulfate 2.0g
CD-4 5.0g
Water to make 1.0L

Oh, yes. One last thing. I simply do not have the scale that tech reps visit me and assist me with problems. My scale is a bit to small, I suppose. Vage guess, most others in this forum have a similar situation. I am already happy if I get a reply from big companies at all.

But maybe one of those reps could join the forum

Martin, I cannot disagree with anything you say.

If it works, it works. I only wished to point out possible pitfalls. There is a review nearly 10 years old now, showing characteristic curves of one type of color negative film in 6 developer formulas, and the results are strikingly different. The results would vary but only direct comparison would highlight the errors introduced by the developers.

I say that if the developer works, use it. If you are happy with it, use it.

The formula I have is totally different than the one you have above, but since I don't wish to lose any negatives, I refrain from hand mixing color developers, so this formula remains untested. It may be a current mutation or an old variant. It might be one only used in research for testing. IDK. Since I turned in all of the formulas I had, my only resources are memory and patents.

I do know that KI and two additional ingredients for sequestering and stabilizing the developer are present in the real developer formulation. The Kodak MSDS lists some of these ingredients and a possible concentration range, but I have not looked at them for a year or more.

That is about all I can add.

PE

Photo Engineer said:

I do know that KI and two additional ingredients for sequestering and stabilizing the developer are present in the real developer formulation. The Kodak MSDS lists some of these ingredients and a possible concentration range, but I have not looked at them for a year or more.

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Most people that mix thier own are using it one shot and mixing with distilled water. Kodak faces much tougher requirements then we do.

Martin Althoff said:

In that sense, if you could look at this formula (source early in this thread) and a) make suggestions as what to add, remove or modify b) and, this is in line with my original intent of this thread, because Hydroxylamine Sulfate is considered too unhealthy and therefore difficult to get, how that can be substituted.

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I'm not the person you're addressing, but on the issue of hydroxylamine sulfate, have a look at (there was a url link here which no longer exists) It lacks hydroxylamine sulfate. It also lacks any form of iodide, unless I've overlooked something, so if you wanted to follow PE's advice on this, you might want to experiment with adding a bit of it. NCF-41 is certainly not a "correct" developer in the sense that PE seems to be using the term, but it does produce color negatives that I've been able to scan. (I've not yet progressed to conventional color printing, though.)

I've just started with color processing, and I've tried both NCF-41 and Paterson Photocolor II developer. I've not done enough to be really confident of which one works better, although I've very tentatively identified some patterns: NCF-41 might be producing some color shifts in Konica-Minolta film, but not (or not as strongly) in Fuji or Agfa film. (My Konica-Minolta rolls happened to be tricky subjects, though, which might have thrown off VueScan's color tuning.) The one roll of Ilford XP2 Super (chromogenic B&W) I ran through NCF-41 also came out very thin, so either I screwed up badly and didn't realize it or these two aren't a good match. Maybe extending development time would help; at least you wouldn't need to worry about color shifts with XP2 Super. Photocolor II hasn't done anything suspicious, but I've run fewer rolls through it (and none of XP2 Super, as of yet). I'm going to run at least a few more rolls through both NCF-41 and Photocolor II; neither developer has yet done anything bad enough to make me want to pour it down the drain, although I don't think I'll be doing more XP2 Super in NCF-41.

PE: Thanks! I should add that all C-41 work is done on test shots. I have a reel of important material sitting here. I would not process that in any C-41, homebrew, brandname, whatever, until I know I can produce stable, calculateable results in my setup and way of working. With B&W I would be a bit more risky simply because its is not as sensitive and I am much more aquainted with it.

Nick: Just mixed up a new batch of chemistry (Fotospeed) with destilled water, demineralized actually, and seem to have lost one 'effect'. The shadows in some, not all, -2 exposed shots had a slight magenta cast. Though I am not to sure on really attributing that to the cleaner water.

srs5694: Great that you jumped in. Thanks for your experiences. Good to know. I have to start writing up mine with Fotospeed. I am new to C-41 self processing myself. Pushing a roll through a minilab I don't think counts

After my first film was completely bad - all the mids and shadows were green (completely underprocessed) - I went for systematic testing. I have done about 8 runs just with water to see how the temperature drop (from ca. 40C to 38C after about 20..30sec). Next were runs the cheapest film I could find and done test exposures. Initially they went from -3..+3, now I am back to -1..+1. I would do a series of test charts and 'real' situations where I would take notes on spotmeter readings of the scene. Suggestion for testing: take the same shot sequences 3x over, cut the film into thirds and process each part under different conditions. Promised, more details in a new thread on Fotospeed

For the record: Claire from jdphotochem.com has replied! They'll mail it all to the UK! And yes the postage is a bad. About 3.5kg, slow option US$47 (up to 8wks), quick US$ 87. Order volume US$ 87.