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  1. #21
    gainer's Avatar
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    Incandescent bulbs change with time, even halogen bulbs. That is why I asked about the consistency of corrections from one session to another. Are they always in the same direction? It seems that the only possible causes are the ones you are either reluctant or unable to measure. Surely you have a light meter for use with your camera. At the beginning of each session and at the end, remove the enlarger lens and measure the incident light at the lensboard. Whatever the ultimate cause of the inconsistent prints, this measurement will show if it is the light source.
    Gadget Gainer

  2. #22

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    Quote Originally Posted by gainer
    At the beginning of each session and at the end, remove the enlarger lens and measure the incident light at the lensboard.
    If you measure at the lensboard, make sure the bellows are always at the same extension, otherwise the measurements will be meaningless.

    I'd still look into using distilled water for the dektol, and seeing if the inconsitencie remains.

    Another thing no one else mentioned is paper batches. Although I'm sure different batches wouldn't result in 25% difference in time, exposure to heat and/or cold might. You mentioned that the darkroom is in your garage, do you store your paper there?

    Same goes for the dektol, I'm sure.

  3. #23
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    As a few have mentioned maybe it is a combination of factors. I store the Dektol in the garage/darkroom where it can get up to 85 degrees in the summer and down to 55 degrees in the winter. But I store my paper in my bedroom where it is a consistent 70 degrees year round. Maybe I might be better off using a liquid developer like Ilford Universal (concentrate) and just dilute right before printing using distilled water . I used it for the first few months and changed to Dektol for some reason even though I was happy with it. Also I will try to be more consistent with the developer temperature having it vary only a few degrees. Believe it or not I don't have a regular light meter. Just the MR meter that attaches to the Leica so it might be more difficult to judge the enlarger light. If I remember correctly when I attempted to duplicate a print over the weekend it came out darker with very slightly more contrast. In the past I can't quite if the prints were darker or lighter.

  4. #24
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    Short on Exposure?

    I remember working in a downtown area that had heavy electrical motors kicking-in every 10 to 20 minutes or so. I also hade two of the old oil capacitor Solar stabilizers to keep the voltage constant. Nevertheless, fluctuations still occurred (B&W) in batch printing that drove me nuts. I was processing 100 prints at a clip in baskets in a jacketed 20X30 nitrogen-burst tank processor. I knew the bulbs were fluctuating intermittently and I was loosing an unacceptable number of prints. After trying everything else, I simply increased the exposure time (3x). It took longer to expose the prints, but I didn't lose any prints and repeat batches were consistent. Since you are tray processing, if your problem is traceable to voltage fluctuations, try increasing your exposure time until the observable fluctuation is less than a third of a stop (voltage fluctuations are time/intensity dependant). Any remaining difference you can control in the tray. In small batches, it is always better to use fresh developer and fresh developer is always 'hot', but remember, if you let Dektol set (even a few days) is will oxidize and give observably different results (lower contrast, increased developing time). A good control test to solve the problem is to expose a strip of your paper without any negative in your enlarger (make sure its focussed correctly) and vary the exposure until you achieve about a 25% uniform gray (don't tear the paper, cut it with scissors).Expose about 25 small strips in this fashion and store them with your unexposed paper. Prior to each new printing session, process an exposed strip and adjust (if necessary) your processing (or exposure) times accordingly. The rest is simple.


    Quote Originally Posted by geraldatwork
    As a few have mentioned maybe it is a combination of factors. I store the Dektol in the garage/darkroom where it can get up to 85 degrees in the summer and down to 55 degrees in the winter. But I store my paper in my bedroom where it is a consistent 70 degrees year round. Maybe I might be better off using a liquid developer like Ilford Universal (concentrate) and just dilute right before printing using distilled water . I used it for the first few months and changed to Dektol for some reason even though I was happy with it. Also I will try to be more consistent with the developer temperature having it vary only a few degrees. Believe it or not I don't have a regular light meter. Just the MR meter that attaches to the Leica so it might be more difficult to judge the enlarger light. If I remember correctly when I attempted to duplicate a print over the weekend it came out darker with very slightly more contrast. In the past I can't quite if the prints were darker or lighter.

  5. #25
    gainer's Avatar
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    I suggest you try measuring the light at the lensboard with different extensions to see if the theory that length of bellows extension makes a difference is true. The film plane is not a point source. This is easier to check than it is to worry about.
    Gadget Gainer

  6. #26
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    Good point Andre'

    It is an established fact that CHLORINE reduces the strength of many chemicals, particularly those used for photographic purposes. Here in the UK, particularly London,
    it is put into our drinking water whether we like it or not. But teeth are said to last longer with it!
    'Determine on some course more than a wild exposure to each chance' The Bard.

  7. #27

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    Quote Originally Posted by Stan. L-B
    Good point Andre'

    It is an established fact that CHLORINE reduces the strength of many chemicals, particularly those used for photographic purposes. Here in the UK, particularly London,
    it is put into our drinking water whether we like it or not. But teeth are said to last longer with it!

    Yup, Chlorine (the swimming pool stuff) and fluoride are commonly found in the drinking water of developed nations. The U.S. has this too, and regardless of nation, minerals are found in the water, though to different degrees. I think that North Texas, where I live, has pretty hard water (that is, high in minerals). This is noticeable when I develop film. The diafine (distilled water) is mild in color, but the water stop that comes after it (tap water) becomes dark in color within a few minutes of leaving the tank. Really amusing when you've done nothing but develop film all day.

    Alright, enough typing for now, I gotta go deliver some pizzas (new job).

  8. #28
    gainer's Avatar
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    Heart attacks are fewer in areas of hard water, unless you count those caused by stress due to problems with developer.

    Chlorine, fluorine and oxygen in water can cause loss of activity in ascorbate developers. Excess sodium ascorbate or sodium erythorbate (aka sodium isoascorbate) can cure it.

    I have a Leica M3 with clip-on meter that would probably work. I'm not familiar with your meter. The object is to measure the output of the lamp, which can be done consistently by making the bellows as short as possible, removing the lens or lens board, and placing the meter right at the opening.
    Gadget Gainer

  9. #29
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    Gainer,the clip on meter I have was made by Leica (actually for) that couples to the shutter dial. I could probably use that to check the lamp as you suggested. Although since my exposures within a session are consistent I doubt that is the problem. Sometimes to check an exposure I'll leave the darkroom with a wet print and put it in the microwave to simulate dry down. So from the time I exposed the print/developed/fixed/dried/maybe had a snack could be 20-30 minutes. When I make an exposure change whether I'm satisfied with the change or not it usually is consistent. But it is still good to know.

    I will however use distilled water to mix the Dektol and then again when I dilute it 1 +2 for the session. I am going to throw out the Dektol I mixed last week and start again since it is cheap enough. I will also certainly be more consistent with the temperature of the developer.

  10. #30

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    good luck, gerald. let us know how it turns out.

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