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  1. #1

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    difference between home- and lab-developed negatives

    I develop my 35 mm film at home, I use c-41 fuji or Tetenal chemicals, and normal fujicolor film... I've been doing it for a while, it's not something I do only once in a while as a fun hobby or something, I'm serious about it, so I'm always careful with details, I use the exact right temperature, don't use exhausted chemicals, etc. And I do get very good results, I am totally happy with what I get.


    BUT... Yesterday in my archive, I found some rolls (10 or so) that a lab had developed for me last year. I took out the negatives immediately and put them next to the negatives I had developed at home (I used many different rolls for comparison, so that it's not biased).


    There is some serious difference!


    The lab negatives clearly have more contrast. My negatives usually have a brownish mask on them. My negatives look a little too yellow, while the lab negatives have a dark magneta tone. I see that in the photos as well, the lab photos have a beautiful magneta tone (not too much).



    So, firstly, how do you compare home- and lab-developed film? I want to know, can you say that with a machine you basically can get much better results (given that it's a good lab and that they take good care of everything)?


    And also, please give me some input on the brown/yellow mask and lack of contrast in my negatives, what can be the cause? What can I do to improve that?


    Help me think.
    Last edited by futile1981; 06-16-2012 at 06:47 PM. Click to view previous post history.

  2. #2
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    Good home and lab developed films should be virtually identical. Mine are just that.

    If they differ, you or the lab are doing something wrong somewhere.

    Negatives should be clear orange with negative dye images. Otherwise they have retained silver or silver halide, or they have some other fault such as under development.

    PE

  3. #3

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    For reasons of economy many commercial labs use their chemicals to exhaustion. The belief is that any color shift can be corrected during printing. This caused one photo writer to remark that their were only two primary colors; puke and burple. Puke is greenish yellow and burple is bluish purple. Prints are usually too puke or too burple. You need to find a reputable lab. As for your own negatives, developing color film is not difficult but denands attention to such things as time, temperature, and agitation.
    Last edited by Gerald C Koch; 06-16-2012 at 07:02 PM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

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  4. #4

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    Dear futile.

    I had different masked films during my earlier attempts too. In my eyes this is a side effect of the BLIX.

    Since years now I use separated bleach and fixing bathes, and the mask is virtually identical to good commercial results.

    About the contrast difference…
    Personally I like negatives more, who are a bit on the soft side, so if you can print them well (optical print, no scan) I would be happy with the result.
    BUT if the chemicals are fresh, development time and agitation are OK, this sounds somehow like under temperature. What is your developer temperature if you drain it? Maybe you have to increase the process temp a bit to get the 100 degrees F in the average.
    If you do a dry prewarm step, how long do you exercise it? I’ve found that nothing below 30 min. is sufficient to prewarm the films / reels and the drum. (maybe my cellar is a bit fresh..). This is why a lot of people prefer a wet prewash with temperated water (preferable 2 cycles, each 30 sec.) prior development.
    There are divided opinions about this prewash, on the one side it’s minimizes the temperature drop of the developer (filled in to cold drums), on the other side it leads to minor variations of the colour curves. In the very most cases this is not noticeable with bare eye.
    A further method to get less temperature drop is simply using more developer. One litre for 4 films (135/36) are doing quite well. By the way, this leads to a further idea. These 4 films per litre in one run, are anyway THAT standard. If you decide to take (for example) a jobo multitank 5 and use only these 560 ml of chemicals, as stated on the drum, you are exhausting the developer too much. (at least if developing the regular 3:15 min)

    Regards,
    Stefan

  5. #5
    foc
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    "For reasons of economy many commercial labs use their chemicals to exhaustion"

    I find that hard to believe. The cost of commercial chemicals for labs and minilabs is quite small compared to the over all operation of a lab. The chemical cost of C-41 processing in a minilab can be as low as 0.30 Euro depending on the purchasing power of the lab. Most minilabs use leader card film processors. These machines are are very reliable, if properly maintained, and will produce excellent results. The chemicals for these machines are mixed internaly in the machine and the processing tanks are automaticly replenished on the amount of film processed. Therefore the chemicals never get a chance to be exhaused.

    Since these processors are automated, they will pump new chemical into the tanks. If for some reason this can't happen, the machine will alarm and not allow any further processing to take place. If the chemical level should drop in a tank the same will happen. If no new chemical is added to the machine, again the same will happen. If for some silly reason the operator tries to reprograme the rep pump rep rate, to try and save chemical, the tank level will drop and the machine will alarm and not allow any further processing to take place until the error is sorted.

    What can cause C41 processing problems in mimilabs and bigger labs is not maintaining the C41 process. By this I mean good housekeeping, processing and reading process control strips, washing cross over racks, measuring rep pump output etc. If this isn't done then the lab is flying by the seat of their pants regarding quality control and frankly in my opinion shouldn't be in business.

  6. #6
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    With replenishment, there is no such thing as exhaustion! So, using to exhaustion implies that the lab is not replenishing, but I know of no lab that does not replenish. In fact, most machines (IIRC), signal the operator regarding replenishment rates and etc. I have to agree with "foc".

    PE

  7. #7

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    Hey Stefan,

    that's such a good point about the BLIX! I do suspect that it has sth to do with my BLIX because I can see that my developer is fresh and clear. In the Tetenal chamicals I get, there is one BLIX, bleach and fixer are not separate, I used to use fuji chemicals for a short while and fuji does have separate chemicals...

    So you recommend that I use separate bleach and fixer? What chemicals do you use?



    The temperature... Although I'm very careful with that one, but now that I'm thinking about it, recently I've been pre-washing less and less, I usually use water, but many times I have ignored it recently... And thinking some more about it, it makes perfect sense; if my film/tank is at room temperature (20) and I add my developer which is usually at 38, the difference in temperature is so high that I guess it would make the developer lose half a degree immediately!


    You had two very good points, I really really appreciate it!



    Please don't forget to comment on my first question, the chemicals, what you used to use before and what you're using now


    Reza

  8. #8
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    Do a forum search for C-41 blix, you'll find a lot of stuff. The Tetenal process is not a standard C-41 process but their own variation, so everything is possible. Photo Engineer has stated over and over again that blix with C-41 film is likely to cause problems. On the other hand, it has worked just fine for many people. However this might be a cause. I don't buy Tetenal anymore.

    For the temperature, you can use TWO successive pre-wash steps with carefully measured water temperature. Make sure to drain the water well before pouring in the developer. However, this would cause a minor shift in contrast and color, not noticeable with bare eye from the negs. Something is really wrong if the Dmin looks notably different within the same film. But, don't forget that between different films, there are differences in Dmin color, and hence, only the end result is meaningful.

  9. #9
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    There are reports here of the single part blix being the lowest quality, and the two part blix being acceptable to the users. No one here (AFAIK) has done a side by side comparison. I have! All film blixes commercially available have some degree of the "bleach bypass" syndrome. Desaturated color, higher contrast, and grainy pictures.

    You are the only possible judge.

    PE

  10. #10

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    Dear futile.

    A Blix is not the best option, if it is fresh and active it will work OK, but leaves a different coloured mask. This is visible, but at most times not a big problem. Adapt filtration and you should get fine prins. The basic problem with the blixes is to keep them stable and active in the needed concentration (Reductive and oxidative components decomposes themselves). So the shelf life is quite short, depending of the desired quality it is more a expensive one way product. Don’t use these monopart chemicals at all.
    In lower concentrations, as needed for processing paper prints, a blix works fine…

    But in my eyes your problem is still focused on the temperature / activity of your developer. You will have at least 2-3 degrees Celsius temperature drop if you develop without sufficient prewarm/prewet. This leads to a quite a noticeable underdevelopment, as you remarked.

    Do some measurements, take a complete drum with reels, fill it with an equivalent amount of temperated water, imitate your normal agitation and measure the temperature in the drum after 1:30 till 2 min. and after 3:15 min. Than you easily can calculate how much the temperature declines, and what your actual average processing temperature is. Don’t be too scared

    Do the same experiment with a prolonged prewarm or a double prewash step, you will see that the temperature drop will be a lot less!
    Than increase your process temp a slightly, maybe to 102 °F and see what you get in a new run.

    Now you will have quite a well approach to the desired temperature, and maybe have to add 10-15 sec to the development time for fine tuning. If you do not over exhaust your developer (1 Litre / 4 Films 135/36 at 100 asa) you / your films should doing fine now.

    My favourite chemicals, will not help you very much, the developer is homebrewed, the bleach is a champion /mydoneg air bleach, fixer is tetenal NQ-3 (both minilab chemicals). Prior homebrewing I had flexicolor (lovely) and tetenal but most times separated bleach and fix stages, it is simply a lot cheaper (and better) in the long run.

    Regards
    Stefan

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