benefits of c41 at lower temp?

Discussion in 'Color: Film, Paper, and Chemistry' started by wilfbiffherb, Feb 2, 2012.

  1. wilfbiffherb

    wilfbiffherb Member

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    im into developing my own film and the rollei digibase kits i use are come with instructions for lower temps. i have always processed at 37.8 but was wondering if there are any benefits of developing at lower temps at all??
     
  2. Photo Engineer

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    The results at lower temperatures can be quite inferior to those at 100F (37.8C).

    PE
     
  3. Greg Davis

    Greg Davis Member

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    I did a practical test and posted it in the thread about the Digibase chemicals using the various times and temps they give. The cooler the process, the worse the color. It got uncorrectable, even in photoshop, at 68F.
     
  4. James in GA

    James in GA Member

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    I worked C41 & C41RA keep it at 100F hight or low you'll color will shift.
     
  5. Photo Engineer

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    Y'all make my point! Thanks.

    PE
     
  6. keithwms

    keithwms Member

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    Ron, I was wondering about this the other day, how come there is no room temp c41 process? It seems possible. I realize it's probably a complicated issue of solubility, but maybe with a more aggressive solvent... it just seems that room temp c41 would be very convenient. Do you know if any serious thought was ever given to this?

    And when you're done with that can you please invent a c41 monobath? :wink:
     
  7. Rudeofus

    Rudeofus Subscriber

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    The biggest problem I have with "room temperature" processes is that my room temperature changes between 18°C and 35°C over the year, so a true "room temperature" process will never be consistent. In my opinion it's about as tricky to keep something at 38°C as it is to keep it at 20°C, except when room temperature is reasonably close to processing temperature.

    @wiffbiffherb: the biggest advantage of lower temp processing is that it is slower and therefore less likely to exhibit uneven development in home processing setups. Remember that b&w folks tell us to stay away from film&dev combos which require less than 5 minutes and bamm! C41 asks for 3:15 ... like you I have had rare problems with yellow streaks across blue sky (never happens with E6 which devs for 6+ minutes) so my next C41 will happen at 30°C. I'll report what I notice when it takes place.
     
  8. keithwms

    keithwms Member

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    I am not disagreeing at all, but let me offer an interesting counterexample, just for fun. Monobath developers for b&w do their good work on the film in a minute or so, and one of the really nice things is that you can focus on agitating well for that brief period and get very good results. If I remember correctly, Haist makes the argument that monobath gives less problems with uneven development (which is why I started playing with it for larger formats). Now, that's partly because you agitate a lot for a short period and the solution is hardly ever stationary, but of course there are also technical reasons why it works so well with monobaths i.e. the way the developer quickly finishes its work and the fixing action starts right away, locally, so you can't really get overdevelopment. But in general there are more problems with uneven dev reported by people who do stand and semi-stand.... just something to think about for those working with really big negs.
     
  9. railwayman3

    railwayman3 Member

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    I was told by an old-time lab operator, who could remember the C-22 process at "room temperature", that C-41 was far better.....you just needed a suitable stable heating system to bring the solutions up to the right temperature. Presumably, with C-22, you would have potentially needed heating, and cooling in hotter climates?
     
  10. keithwms

    keithwms Member

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    Hmm. So do you remember what wasn't good about C22? I just wonder, with all the post processing that many people do now, maybe certain issues aren't as critical as they once were...
     
  11. Photo Engineer

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    C41 is based on proper diffusion of chemicals into and out of the film at 100F. If you change the temperature, you ruin this process. It involves diffusion in of the developer and out of the DIR fragments and Iodide which control color, grain and sharpness.

    So, almost all C41 films done at room temp seem to suffer from overdeveloped yellow and underdeveloped cyan! And, believe me, I have tried this more than one time. I've even used a water bath after the development step to increase the cyan and "stop" the yellow. It just does not work right.

    C22 was based on slow development with no DIR fragments to control image quality. When DIRs became available, the researchers on that chemistry tried to get the C22 process to work with the new chemistry and emulsions and it just did not work correctly. Something always went wrong. So, they devised C41 and doing so got rid of Benzyl Alcohol and changed from CD3 to CD4 to gain higher activity even at 100F, because they needed this activity due to the DIR fragments which inhibit development.

    Short thumbnail sketch for those interested.

    PE
     
  12. keithwms

    keithwms Member

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    Well what if I used, you know, water spiked with DMSO... I mean if it's just a solubility issue... I know, I know, it's not recommended by the manufacturer, mea culpa...
     
  13. Photo Engineer

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    I've tried DMSO actually, and it did nothing. There are reports of it doing things when making emulsions though. There is this Chinese patent...... :wink:

    PE
     
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  15. Rudeofus

    Rudeofus Subscriber

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    As you said yourself, monobath is a process which works to completion, so it's quite difficult to get unevenness. Semistand gets its unevenness not from long development but from uncontrollable liquid motion in the bath: hot D-8 would yield unevenness from stand development after only a few minutes. What should be a homogeneous diffusion process is in fact dominated by chaotic streams in the dev, so you end up with funny effects.

    I don't know where the uneveness from C41 comes from, like wiffbiffherb I've seen yellow streaks in blue skies. Since I agitate every 15 seconds it's not a stand development kind of problem.
    Tetenal states a range of 30°C to 48°C for their C41 kit. They recommend 38°C if possible, apparently this yields the best results for most. But sometimes processing at a different temperature is more desirable even if this means potential draw backs in image quality.

    The biggest defect from low temp development according to what you write is a color cast which is different in mid tones, shadows and highlights and therefore not correctable by pure analog means. This would, of course, be completely unacceptable in any commercial process, but to me a color cast is more acceptable than the kind of streaks that I have seen and which the thread starter posted.
     
  16. jbl

    jbl Member

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    PE, is this because the yellow layer is on top? I'm still trying to wrap my head around this of which layer is first and how the colors in the negative relate to colors in the positive.

    -jbl
     
  17. Photo Engineer

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    What I describe is called "crossover" in that the blue image is too high in contrast (Yellow dye) and the red image is too low in contrast (Cyan dye). The top and bottom layers do not develop correctly. This could be corrected in PS, but there is no correction possible in traditional RA printing.

    It can also be corrected in 3 color printing in Dye Transfer and the like by adjusting the separation negatives for contrast.

    PE
     
  18. jbl

    jbl Member

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    That makes sense, thanks!

    -jbl
     
  19. keithwms

    keithwms Member

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    So... and I know the gods will smite me for saying this but... we could just as well do c41 at room temp if we're going to use unmentionable processes anyway..
     
  20. Photo Engineer

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    Well, you are on your own. IMHO the crossover is so huge that there is going to be a big problem correcting it with lots of trial and error. If it is outside of the scope of adjustments possible, then you will have a problem.

    And, this begs the issue of whether there will be bumps and kinks introduced into the curves due to the response of the 9 components and whether all C41 films will respond the same.

    You see, I gave the simplistic answer above to a very very complex issue.

    PE
     
  21. michaelbsc

    michaelbsc Member

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    Since when is contrast masking unmentionable!? :wink:

    Actually I have been reading up on it, using real pin registration masks. If I live long enough I'm going to master that.

    Hell, I had to learn Morse code way back when. I may as well add to the pile of arcane skills. You never know what skills might come in handy after TEOTWAWKI. (The End Of The World As We Know It)
     
  22. keithwms

    keithwms Member

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    I wonder if this unmentionable transgression might be of particular use with a maskless c41 material... Rollei D***base CN...

    Obviously the reason why this'd interest me is not to get lab-quality colour. But there are plenty of projects in my noggin, including 100% orthodox analogue ones, that don't require perfect negative colour.

    ~~~

    I actually look forward to TEOTWAKI, Michael. It will separate the talkers from the doers, and the experimentalists from the brandwankers, mighty quick. In one rapturous moment, the people who really understand the processes will ascend, leaving a vast majority scratching their heads in bitter disbelief and cursing an eternity among the pixelated flames of hell :wink: That is when the value of the traditional processes will start to really surprise people. Talbot and Niepce and all the rest will arise from the depths and kick some modern lazy ass.
     
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  23. Photo Engineer

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    Keith;

    Its "TEOTWAWKI". :D

    Tsk!
     
  24. keithwms

    keithwms Member

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    Geez Ron WTF!

    Sorry TEOTWAWKI... TEOTWAWKI... come, oh Teotwawki, come save us from eternal pixelation....
     
  25. keithwms

    keithwms Member

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    Actually I wonder if we shouldn't refer to this more correctly as TEOTWATKI :wink:
     
  26. Photo Engineer

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    I couldn't resist!