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Thread: C41 Chemistry

  1. #1
    Adrian Twiss's Avatar
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    I have always shied away from developing my own C41 because of the very short development times and (to a lesser extent) the high processing temperatures. My very few attempts were less than satisfactory. Does anyone know of a brand of C41 Chemistry that can be used in the 20-22 degrees Celsius range and have a developing time of around 5 minutes.

    My local processor (who is very good) can turn 35mm films around in about an hour but takes a week to process roll film. Changing processors is not an option

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    Ed Sukach's Avatar
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    Quote Originally Posted by Adrian Twiss
    I have always shied away from developing my own C41 because of the very short development times and (to a lesser extent) the high processing temperatures. My very few attempts were less than satisfactory. Does anyone know of a brand of C41 Chemistry that can be used in the 20-22 degrees Celsius range and have a developing time of around 5 minutes.
    I just checked the Tetenal C41 data sheets: Their "Press Kit" - Dry chemicals to make 1 Liter - specifies the usual 38 degrees C (100F) and 3' 15" developing time. Their 5 Liter C-41 Kit also specifies and "urges" 38 degrees C for 3' 15' but additionally lists 30 degrees C (86F) and 9 minutes flat developing time for the first film run - increasing to 11 minutes for the 13th - 16th film.

    I've done a few hundred rolls of 120, and a lesser amount of 35mm - mostly using a JOBO Processor - but there have been times when I have mis-set the temperature four or five degrees C either way - and I've seen *very little* effect on the film... color balance - contrast, grain ... whatever. I would not consider C-41 processing to be nearly as sensitive as *some* claim.

    ALso, I am *convinced* that the "no less than five minutes" requirement - at least in color - and for Irving Penn, processing Tri -X in UFG for "three to five minutes" - is a myth. All of my C-41 has been developed for three (3) minutes, fifteen (15) seconds.
    Tetenal does have a caveat of a "possible color crossover" at 30 deg. C. Personally I wouldn't worry about it. Then again - I print my own RA-4, so I have the luxury of "fiddling around to get things right" after the fact.

    Tetenal DOES make a RA-4 kit "Two Step"???? "Mono??? kit for color printing that does operate, normally, at 22 degrees Celsius - I've used that one and I like it very much.
    Carpe erratum!!

    Ed Sukach, FFP.

  3. #3
    Adrian Twiss's Avatar
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    Ed

    Thanks for taking the trouble to research this for me. My problems are not specifically with maintaining a consistent temperature (although I appreciate that this is important) its more the very short development times that I find difficult. With the Jessops own brand I used to use development was at about 40 degrees and took 21/2 minutes. I do not intend to use my Jobo processor for developing films. I will use my trusty Paterson tank (with dedicated reels reserved exclusively for colour processing).

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    AllanD's Avatar
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    I assume that by Jobo you mean a Jobo rotary processor. If soÖ.

    The Jobo will half your chemistry bill, which must be worth it if you are using the rather expensive Jessop kit. If you have got the Jobo, why not use it ?

    I haven't seen any low temperature kits, but then, with the Jobo CPE2, I don't need one. I suspect that if Tetinal (http://www.tetenal.com) doesn't do one, the demand for such a thing just is not there.

    Short developing times are not a problem, as the film and chemicals are made for rapid processing in a commercial environment. However, if you tend to slightly over process, you will get more contrast and a little more colour saturation, both of which could be countered by shooting on Reala, or printing on a ďportrait paperĒ.

    If you are printing your own RA4 (or scanning for digital), you have some scope for experimentation with time/temperature, as colour shifts can, to a certain extent, be corrected.

    For what its worth, I make up my own C41 chemistry using the recipe given in the Rayco handbook (http://www.rayco-chemicals.co.uk). This has a recommended process time of 5 minutes at 35 degrees when hand processing. Iím at work, so I canít give you agitation details, but I think they are essentially the same as for most types of B/W film. Their gloop uses a standard ďall in oneĒ colour developer ( either CD3 or CD4 Ė canít remember which ), so the active ingredient should be equivalent in potency to that in premixed developers, so this time/aggitation regime may work for you. Anyway, itís a start !

    By the way, with the CPE, I run at 36-37 degrees( depending on the ambient temperature), which allows for the inevitable drop in temperature, even with a water bath. I think Jobo mention this technique on their website. (http://www.jobo-usa.com).

    I started this chemical mixing madness when work commitments meant that my chemicals were going off faster than I could use them. Unfortunately, such an approach requires an investment in hardware (scales, pH meter) although these can be offset by lower chemistry costs, especially when compared to low volume ďconsumerĒ kits like that sold by Jessops. The Rayco recipe has always given me good results, although I print my own RA4, so Iím probably getting away with a lot ! Canít say that I would recommend this approach to anyone who is not already chemically insane !

  5. #5
    Ed Sukach's Avatar
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    Quote Originally Posted by AllanD
    However, if you tend to slightly over process, you will get more contrast and a little more colour saturation, both of which could be countered by shooting on Reala, or printing on a ďportrait paperĒ.

    By the way, with the CPE, I run at 36-37 degrees( depending on the ambient temperature), which allows for the inevitable drop in temperature, even with a water bath. I think Jobo mention this technique on their website. (http://www.jobo-usa.com)
    One other method of controlling contrast is to "pre-flash" ... using a gray negative and exposing the paper for 10% to 20% of the analyzed exposure, and then printing the image for the remainder - as you would normally. Works wonders.

    Some time ago I had to return my CPP2 to JOBO for repair ... the main problem was that water was capillary-ing up the pump shaft through defective potting and into the control unit - causing havoc with the temperature control. Took a while for them to find that out - the water would only arrive after some ten minutes of operation.
    I borrowed one of the High-end Kodak Laboratory thermometers to check out the temperature regulation - and after a telephone call to JOBO's customer service they told me they routinely set the outgoing water bath temperature "high" by a degree or so to compensate for thermal losses in operation. They recommended setting the temperature to where it "should" be - and that has worked well.

    BTW - WELCOME!! It's great to have someone on board working with color!!

    I'll check out that web site for chemicals ... I did get a "recipe" from Photographers' Formulary for C-41 chemicals - I haven't tried tried it yet. At one time they did produce a "Kit" but the demand wasn't great enough to justify continued production.
    Carpe erratum!!

    Ed Sukach, FFP.

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    AllanD's Avatar
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    Sorry, but the web-site doesn't have the recipe; they have a book that contains the recipe ! I'm not sure what the legal implications are if I put it out on this forum.

    I measure temperature using a digital thermometer, which I've compared to my Jobo "high resolution" mercury thermometer. Both point to the my CPE being about right on the temperature setting. However, I think the best plan is to measure the temperature of the developer directly, rather than rely on a thermostat.

    I rather glad that digital has caused the price of these processors to crash. I would hate to have paid full price for one. Has your sprung a leak yet. Mines held together with silicon sealant !

    Thanks for the welcome

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    Adrian Twiss's Avatar
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    Alan

    Thanks for the input. I tried the Jobo (as I have the necessary developing tank) but got dreadfully uneven development. No doubt it was my fault. I don't have a lift on mine so it was awkward getting the timing right. The development time was even shorter because of the constant agitation.

    I would welcome any advice about the correct way to use a Jobo processor for film processing. I assume you use the slowest rotation speed possible but do you use rotary agitation or the rocking agitation?

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    Ed Sukach's Avatar
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    Quote Originally Posted by Adrian Twiss
    I tried the Jobo (as I have the necessary developing tank) but got dreadfully uneven development.... I don't have a lift on mine so it was awkward getting the timing right. The development time was even shorter because of the constant agitation.
    I would welcome any advice about the correct way to use a Jobo processor for film processing. I assume you use the slowest rotation speed possible but do you use rotary agitation or the rocking agitation?
    Uneven development is *usually* caused by insufficient chemistry volume, an improperly levelled tank, or some sort of chemical contamination - holdover from color developer to bleach fix. If I remember correctly -- this is always a gamble -- you have a CP2 - and from the above, are using the magnetic coupling - somewhat more awkward than having the lift ... but not a great deal worse.

    Much depends on film size - with 35mm and 120, "P" rotational speed (I have the older model thus labeled) is used - that is about midway along the scale. The rotation pattern should be two (2) turns clockwise, reverse, two (2) turns counterclockwise, reverse, and continue - for all films except 110, which is rotated in one direction only. I'm not sure about the rotation speed for 5" x 4" film - I'd have to look it up. A "too slow" speed could possibly result in uneven development.

    Much has been written about continuos agitation requiring decreased development times - I've already struggled with that idea ... and I've come to the point where I ignore it entirely for C-41 and E-6 development and use the published data. In black and white processing, I "wring out" the film developer-combination anyway and use my own time/temperature, which, incidentally, haven't been that far from the published data - yet.

    If memory serves, manuals for the CP2, CPP2 and most of the other JOBO equipment are available on-line at their web site.
    Carpe erratum!!

    Ed Sukach, FFP.

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    AllanD's Avatar
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    I tend to reduce development time for B/W films. First I adjust for temperature (my CPE has a minimum temperature of 21C), then I reduce for constant agitation, normally about 15%. This gets me my basic time, which I vary if I know the film contains predominately low or high contrast subjects. By the way, be careful if you use Ilford films. Some Ilford datasheets, have tables for both constant agitation and hand processing - use the right one !

    For colour, I have my own process time - but that is because Iím using a non-standard dev. I used the stated time during my brief experience with commercial devs and everything was fine.

    My CPE2 has two speed settings. In my ignorance, I have always used the slowest speed but have since read that Jobo recommend the higher speed. As I never had a problem with uneven development, I havenít made any changes to my regime.

    I have collected several drums over the years and have found that some have worn lids. If you check the outside of the inner rim of the lid you will find several ribs in the plastic. These can wear flat. During processing, the developer does slosh against this seal, so some could be lost. For me, it was more a problem with fixing as the process causes more gassing and the increased pressure made the lid leak. However, if it is really bad I guess a leak could be causing your developer level to drop. New lids are available as a separate part from Nova Darkroom (http://www.novadarkroom.com/)

    The lids have a habit of popping off during the stop cycle (if you use a stop bath, as I do) due to the gassing caused by the reaction of the acid stop and the alkaline developer. Just be ready for it !

    Levelling is important, as is using the drum support cradle. My CPE came without a cradle. If yours is missing, you can make one out of two bits of U shaped guttering, pop-riveted together -> )(

    The only problem I have had is with incomplete fixing, and then only with certain Kodak films (Portra 400). Most of my experience is with Fuji films which always seem to fix quickly and completely. I tend to push my fix to the limit of its capacity, so if I suspect that fixing is not complete I will pop the lid to make sure before starting the washing cycle. This will cause no harm to the film. Under fixing is obvious as a (sometimes opaque) veiling on the film. Apparently, over fixing can cause colour shift, but I have never had an obvious problem.

    My CPE sometimes doesnít do the two turn trick. Mine is an old one that has an external "interrupter" that catches a peg on a four pronged arm. Sometimes the plastic ring that holds the peg gets gummed up. A good clean with dilute bubble-bath will get it moving again. I believe that the later "plus" models, and all the pro models, have an internal mechanism that is more reliable, but are a bugger to fix.

    I do not have a lift on my CPE, but have never found this to be a problem. My normal process procedure is to -

    Get everything - including the drum with the film in it - up to temperature (this takes ages). I use the temperature of the developer as a reference, as everything else is much less critical. You may find that the temperature at the top of the measuring cylinder may be slightly less than at the bottom, in which case a little gentle stirring is required. I take the temperature in the top third of the cylinder. I donít pre-soak.

    • Start the processor turning

      Pour in your dev as quickly as possible. Press on the lid and flip the drum onto the magnet. It should pick up and latch on easily. Start the timer.

      Ten seconds from the end of time, pour the dev away (I use it as a one shot) and pour in the stop. Put the lid on, give the drum a couple of turns end-over-end, pop the lid off to let out any gas, then put the drum on the rotary processor again for a minute.

      Repeat the above for the fix, but using what ever time the fix manufacturer recommends.

      Wash in warm water, stabilise and hang up to dry.


    If the film edge reference numbers are similar in density to one you had commercially developed, your processing canít be far out.

    By the way, as you may already know, you can get two 120 roll films on a single spool. If yours has the red catch on it (not all spools do), you can load one film, press in the red catch, then load the second. If you donít have the catch, you will need to find another way of stopping the films overlapping - as they will due to the rotary action of the processor. Apparently, putting a kink in the trailing edge of the first film will work, but I havenít tried this. Two 120 films processed for the cost of only 240ml of chemistry - canít be bad !

  10. #10
    mts
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    Hello, and I am new to this forum. However, I've been mixing C41 for as long as it has been around, and C-22 before that. In the 1980's, before easy Internet communication, there were publications by P. Dignan and others, and a newsletter that was put out by a fellow named Dale Neville. A lot of people shared information on the formulation of photochemistry for both B&W and color processing, but much of this information is lost to time.

    If you scratch mix, you will pay under $5.00 for a 1-liter batch of C41 that will process at least 8-10 rolls of film and it will last a week or two with proper storage. Your investment in chemical stock and equipment will be in the $300-400 range if you purchase one to five pound quantities. Half the cost will be $150.00 or so for the CD-4 developing agent.

    From these old newsletter sources, and from the photochemistry columns in Darkroom Techniques (now PhotoTechniques) magazine, and from lots of processing experiments developing shots of the MacBeth chart I learned that there are quite a few C41 variations that make color processing economical and relatively easy. The formulae I prefer use separate stop, bleach, and fixing baths. Once you complete the stop bath, the bleach and fix can be done in light, because developement is completed and the developing agents are neutralized.

    I do not deviate from the 100F temperature, because C41 films are designed to produce optimal characteristic curves for the color emulsion layers at this temperature. There is no reason not to use the 100F temperature, because it is easily maintained in a dishpan water bath for hand processing. I place the solution bottles (1-liter) into the pan and fill it with hot (~140F) water, insert an accurate color thermometer into the developer bottle and in about 20 mins. the temperature rises to about 105F. Another shot of hot water for the bath stabilizes temperatures slightly above 100F, where I start the processing using Nikkor reels and tanks.

    Here is the method I use to process C41 one or two rolls at a time in my darkroom sink--no Jobo, no autoprocessors, etc. I load my film in Nikkor reels, and I usually add a few frames cut from a roll of MacBeth chart exposures. In my opinion, the advertising that color is difficult to process and requires automatic equipment is false.

    Once you stabilize your temperature bath at around 101F, pour 500 ml developer into the tank, douse the lights, drop in the loaded film reels, and put on the lid. If you start with solutions and bath at 101-102F, the temperature stays within a degree or so for at least 10 mins. While you develop the film, hold the tank in the water bath. Invert the tank twice every 30 sec and keep it in the bath for 3 mins. Then pour the developer back into the 1-liter bottle and pour in the stop bath.

    Development stops completely and the rest of the processing isn't particularly temperature sensitive, because the bleach and fix steps both carry through to completion without significant effect on the color balance or the characteristic curves of the emulsion layers. Somewhere between 95-100F is fine for the remaining processing, and it's therefore only necessary to maintain the 100F temperature for the 3 mins processing in the developer, and the 15-30 sec that it takes to empty the tank and fill it with stop bath.

    For bleaching it is hard to beat the old C-22 ferricyanide formula. It was changed to an Fe-EDTA formula owing to environmental consideration, and because the bleach and fix can be combined into a blix. Lately I really prefer the persulfate-quinone formulation that is clean working and long-lasting, and cheaper than blix.

    After removing the lid, the stop bath can be poured out and the bleach/wash/fix steps carried out in the sink using a stainless steel stirring rod to agitate the reels. Use solutions from the water bath and don't worry about the temperature. Bleaching takes about 6 mins depending on the formula, and be sure to toss in a 1 min. wash before the fixer. Fixing takes about 6 mins to ensure that you have no remaining silver. The bleach and fixer, when used this way, last through two or three batches of developer. You know when you reach the lifetime of the bleach and fix by noting the increase in time for the solutions to operate.

    After a final wash, and a dip in the stabilizer, your C41 processing is done. Any concerns about crossover or serious processing defects are revealed by processing some known-good MacBeth chart frames (taken on the same film type, of course). For that reason I generally favor bulk-loaded film from the same emulsion batch.

    The formulary I use is available. It can be posted here, or I will be happy to e-mail a copy to anyone requiesting it, in M/S Word .doc format.

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