Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,533   Posts: 1,543,995   Online: 1017
      
Page 1 of 3 123 LastLast
Results 1 to 10 of 21
  1. #1

    Join Date
    Jan 2007
    Shooter
    Large Format
    Posts
    284

    My attempt at E-6, a question

    So I've decided that the cost difference between the at-home Kodak E-6 kit and $12/roll professional development is too great to ignore. I am competent in chemistry and have no fear of precise measurements, preventing spills, etc. I want these slides to look great but I also accept responsibility for my results.

    I've built a water bath to hold the chemicals at precise temperature. Since E-6 prefers continuous agitation and because manual agitation is mind numbingly dull, I'd like to use a rotary processor. I have a Beseler Motor Base.

    I understand that temperature control + time define the exposure for the first developer. I have built a two layer (12 mil thick) neoprene coozy for my steel development tank that encompasses top, side, and bottom.

    In my testing, I preheat both the tank and the neoprene in the water bath. I then pour in '1st Developer', i.e. water which is at 101.0 F. It takes 25 seconds to pour in the 350ml of solution (a 2 x 120 reel tank). I place the coozy on the motor base and measure the temperature at 6 minutes. It has dropped 3.0 F. This is consistent every time.

    I am thinking that the temperature drop is not a problem. I just need to adjust the 6 minutes somehow to compensate for the drop off. Consistency is most important and it seems I've achieved that. How would you adjust the first developer time? Is testing the only option?

    Also, if it takes 25 seconds to pour in the chemistry and 15 seconds to empty, how would you adjust the development time?

    I try to keep the tank parallel to the ground while I am pouring so that the solution is evenly spread along the tank side during the 25 seconds. This is correct?

    Thanks for all your tips. I plan to run a test roll tonight.

  2. #2

    Join Date
    Oct 2006
    Location
    Van Buren, Arkansas
    Shooter
    Large Format
    Posts
    2,412
    Images
    101
    When doing small tank development of E-6 or C-41, I prefer to prefill the tank and drop in the loaded reels into the tank in the dark, and put the lid on and start the time immedidately. It is only that first developer step that has the critical timing. You "could" if you wish, preload your reels and keep them in a paper safe while you fill the tank, if you don't want to load reels after you fill the tank.

  3. #3
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,016
    Images
    65
    You should always prewet your tank and film with water at the proper temperature to pre-temper the tank. It is not clear if you intend to do this. It will help very much to avoid the temperature drop and shock to the film.

    Kodak has a fact sheet for this type of situation that says should you start high and end low, the average temperature should be 100. So, if you drop 1 deg / min, and development is 6 minutes, you should start at 103 and expect to end at 97, for a total delta Temp of 6 deg over 6 minutes. They say it will work, but I have never tried it. I use a CTB to keep things on the dot.

    PE

  4. #4

    Join Date
    Oct 2006
    Location
    Van Buren, Arkansas
    Shooter
    Large Format
    Posts
    2,412
    Images
    101
    Quote Originally Posted by Photo Engineer View Post
    You should always prewet your tank and film with water at the proper temperature to pre-temper the tank. It is not clear if you intend to do this. It will help very much to avoid the temperature drop and shock to the film.

    Kodak has a fact sheet for this type of situation that says should you start high and end low, the average temperature should be 100. So, if you drop 1 deg / min, and development is 6 minutes, you should start at 103 and expect to end at 97, for a total delta Temp of 6 deg over 6 minutes. They say it will work, but I have never tried it. I use a CTB to keep things on the dot.

    PE
    I guess I should have mentioned, in addition to pre-filling the tank with first developer, I keep the tank and all chemicals in a big deep 16x20 hypo tray, with tempered water constantly running and overflowing the tray keeping the temperature right on. I lift the tank out of the water bath to agitate, and put it right back in. The tanks and 1/2 gallon bottles of chemistry are taller than the tray so they sit on the bottom and are surrounded with tempered water.

  5. #5
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,016
    Images
    65
    Pre heating in a water bath does not temper the interior of the tank. Preheating with a solution does temper it. So, you should use the drop temp method Kodak has documented.

    PE

  6. #6

    Join Date
    Jan 2007
    Shooter
    Large Format
    Posts
    284
    PE,

    I had thought of a pre-heating the film and interior with a solution but the Kodak literature advises against a pre-wet step: "note that it can cause sensitometric effects with some emulsions in both speed and color balance. Contact your processor's manufacturer to find out how to disable the pre-wet step." Should I just ignore this and use a pre-wet? I agree, it will definitely help keep the temperature.

    Thanks for the tip on modifying the start temperature so the middle of the delta is 100.4 F. Makes sense. I didn't know if the curve was that linear or something more fancy was required.

    Phototone, I don't have an actual 'dark'room. I use a changing tent and I'd like to keep it completely dry if possible. I don't know know that I could load the reels quickly using my setup but thanks for the pointers.

    Last question: The tank has a volume of 1 liter. I see recommendations to use 1/3 the maximum volume when doing rotary agitation. So, is 350ml the correct solution amount to completely cover the film as it is rotating?

  7. #7
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,016
    Images
    65
    Use the volume suggested for the square footage of film. Do NOT base it on tank type unless the suggested volume is less than the tank suggests. Always use the larger value.

    As for prewets, I have been using them for years and find no problem as long as you do it the same way every time.

    PE

  8. #8
    Thanasis's Avatar
    Join Date
    Nov 2006
    Location
    Sydney, Australia
    Shooter
    Medium Format
    Posts
    392
    Quote Originally Posted by Photo Engineer View Post
    You should always prewet your tank and film with water at the proper temperature to pre-temper the tank. It is not clear if you intend to do this. It will help very much to avoid the temperature drop and shock to the film.

    Kodak has a fact sheet for this type of situation that says should you start high and end low, the average temperature should be 100. So, if you drop 1 deg / min, and development is 6 minutes, you should start at 103 and expect to end at 97, for a total delta Temp of 6 deg over 6 minutes. They say it will work, but I have never tried it. I use a CTB to keep things on the dot.

    PE
    Hi PE.
    What is a CTB?

  9. #9
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,016
    Images
    65
    Quote Originally Posted by Thanasis View Post
    Hi PE.
    What is a CTB?
    Constant Temperature Bath! It is a tank of water and a recirculating pump which has a thermostat that can be set at any temperature. I have one in my Jobo, one is my sink, and I have a third free standing Jobo unit.

    PE

  10. #10

    Join Date
    Jan 2007
    Shooter
    Large Format
    Posts
    284
    If one isn't using a Jobo, how would I rotate the drum in a CTB? Obviously the Beseler base cannot be submerged.

Page 1 of 3 123 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin