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Thread: The new Ektachrome E100, Tetenal E6 and Jobo

  1. #11

    Join Date
    Jul 2013
    Posts
    152

    Re: The new Ektachrome E100, Tetenal E6 and Jobo

    This is from Jobo's 2020 calendar "Pre-Wash
    In this context it is helpful to remark that JOBO clearly recommends to always pre-wash
    your film (and paper) in rotary processing for 2 to 5 minutes. Pre-washing allows the
    emulsion to soften up and absorb first water molecules. Keep in mind that, different from
    inversion processing, in rotary processing chemistry does not hit the whole film surface
    at once. Pre-washing makes sure that chemical is evenly absorbed by the emulsion in
    rotary processing of your film (and paper), avoiding unevenness and undulations on the
    film surface. Our service department found that 99% of customer complaints with unevenness were strictly correlated to the lack of pre-wash. Color-processing times remain
    unchanged even with pre-wash, whilst B&W development times need to be increased by
    an average of 20% compared to B&W development without pre-wash.
    With inversion processing the pre-wash can be skipped as the whole film is always simultaneously immersed in chemistry. Due to the reduced agitation in comparison to rotary
    processing the development times are about 25% longer for inversion processing than
    they are for rotary processing to achieve the same density. As a rule of thumb, you can
    say that developing film in rotary processing with pre-wash will take about the same time
    as inversion processing without pre-wash at any given temperature. Most large format
    photographers know about the challenge of achieving evenness of processing when working manually. The larger the film format the greater this challenge becomes. Apart from
    perfect control of push & pull process, the evenness is one of the main reasons why a
    large format photographer should opt for the JOBO processor with Expert Drum."

  2. #12

    Join Date
    Sep 2012
    Location
    Sunshine State
    Posts
    843

    Re: The new Ektachrome E100, Tetenal E6 and Jobo

    I always believe pre-wash makes a lot of sense for film and photo paper development. Not sure why does Ilford not recommend pre-wash for its film development.

  3. #13

    Join Date
    Dec 2014
    Location
    Iowa City, Iowa
    Posts
    1,178

    Re: The new Ektachrome E100, Tetenal E6 and Jobo

    Quote Originally Posted by nbagno View Post
    This is from Jobo's 2020 calendar "Pre-Wash
    In this context it is helpful to remark that JOBO clearly recommends to always pre-wash
    your film (and paper) in rotary processing for 2 to 5 minutes. Pre-washing allows the
    emulsion to soften up and absorb first water molecules. Keep in mind that, different from
    inversion processing, in rotary processing chemistry does not hit the whole film surface
    at once. Pre-washing makes sure that chemical is evenly absorbed by the emulsion in
    rotary processing of your film (and paper), avoiding unevenness and undulations on the
    film surface. Our service department found that 99% of customer complaints with unevenness were strictly correlated to the lack of pre-wash. Color-processing times remain
    unchanged even with pre-wash, whilst B&W development times need to be increased by
    an average of 20% compared to B&W development without pre-wash.
    With inversion processing the pre-wash can be skipped as the whole film is always simultaneously immersed in chemistry. Due to the reduced agitation in comparison to rotary
    processing the development times are about 25% longer for inversion processing than
    they are for rotary processing to achieve the same density. As a rule of thumb, you can
    say that developing film in rotary processing with pre-wash will take about the same time
    as inversion processing without pre-wash at any given temperature. Most large format
    photographers know about the challenge of achieving evenness of processing when working manually. The larger the film format the greater this challenge becomes. Apart from
    perfect control of push & pull process, the evenness is one of the main reasons why a
    large format photographer should opt for the JOBO processor with Expert Drum."
    Can you provide a link. What is the calendar? Is this literally a 2020 calendar, one you can hang on a nail?

  4. #14

    Join Date
    Jul 2013
    Posts
    152

    Re: The new Ektachrome E100, Tetenal E6 and Jobo

    Quote Originally Posted by Duolab123 View Post
    Can you provide a link. What is the calendar? Is this literally a 2020 calendar, one you can hang on a nail?
    Oops, typo. Should have said catalog, not calendar. Link Here

  5. #15

    Join Date
    Dec 2014
    Location
    Iowa City, Iowa
    Posts
    1,178

    Re: The new Ektachrome E100, Tetenal E6 and Jobo

    Quote Originally Posted by nbagno View Post
    Oops, typo. Should have said catalog, not calendar. Link Here
    Thanks so much. This is the first time I've seen this much info from Jobo.

  6. #16

    Join Date
    Nov 2013
    Posts
    142

    Re: The new Ektachrome E100, Tetenal E6 and Jobo

    In my experience with prewash in Tetenal E-6 is that it causes a color shift.
    If anyone interested, my FD times in Tetenal E-6 (manual rotation @ ~42 RPM) are:

    1st reuse: 6:40
    2nd reuse: 7:00
    3rd reuse: 7:30
    4th reuse: 8:00

    Control strips:
    https://www.instagram.com/p/BrAtzt8gbsF/

    JaZ

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