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Thread: Possible Uneven Processing with BTZS tubes

  1. #1

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    Possible Uneven Processing with BTZS tubes

    I've been having issues with negatives turning up slightly more developed on one side as if their is a line sort of in the middle. I've just started using BTZS tubes with 4x5 film. I use Clayton F76 and follow the directions of filling all of them and then shaking for 15s then rolling the rest of the development time. I wonder if maybe I'm not getting some of them shaken enough or if the first one I fill is sitting too long before I get to shaking all of them.

    Any thoughts?

    These "scans" are just quick pics with my digital Ricoh on a light table but if you look at the middle you should get an idea.(the left side is a glare from another lamp I had on in the room)


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  2. #2

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    Re: Possible Uneven Processing with BTZS tubes

    Quote Originally Posted by Mexipike View Post
    I wonder if maybe I'm not getting some of them shaken enough or if the first one I fill is sitting too long before I get to shaking all of them.
    I guess it has to be that, left side looks as having been depeloped a longer time.

    Just expose two equal sheets and test it, rolling one without a delay and the other one after 1min, you will see that 1min of development has an important effect.

  3. #3

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    Re: Possible Uneven Processing with BTZS tubes

    Sorry, I'm a bit confused about how you're processing with the tubes...

    You should have an extra set of caps filled with developer just before turning off the lights. Then, you unscrew each tube, in the dark, and screw onto the caps filled with developer. At this point, no developer is touching any film. Once you've got all the tubes transferred, turn on the lights, grab the tubes and shake for about 10 secs. Toss into the water bath and immediately start spinning.

    I've done this with the 8x10 tubes for nearly 30 years without a single hiccup.

  4. #4

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    Re: Possible Uneven Processing with BTZS tubes

    Quote Originally Posted by Alan9940 View Post
    Sorry, I'm a bit confused about how you're processing with the tubes...

    You should have an extra set of caps filled with developer just before turning off the lights. Then, you unscrew each tube, in the dark, and screw onto the caps filled with developer. At this point, no developer is touching any film. Once you've got all the tubes transferred, turn on the lights, grab the tubes and shake for about 10 secs. Toss into the water bath and immediately start spinning.

    I've done this with the 8x10 tubes for nearly 30 years without a single hiccup.
    I do it that way.

    I guess I was worried about the part where I pour the chemical in still getting some chemical on the negative causing uneven development but I suppose that itís probably not an issue and somehow I didnít start shaking soon enough or do it enough.

  5. #5
    Steven Ruttenberg's Avatar
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    Re: Possible Uneven Processing with BTZS tubes

    Here is what it looks like convereted. Something caused it to have different exposure on left than right and it also looks like some issues with enven development or swirls, etc.
    Attached Thumbnails Attached Thumbnails R0002930v1.jpg  

  6. #6
    Resident Heretic Bruce Watson's Avatar
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    Re: Possible Uneven Processing with BTZS tubes

    Quote Originally Posted by Mexipike View Post
    I do it that way.

    I guess I was worried about the part where I pour the chemical in still getting some chemical on the negative causing uneven development...
    Those two statements are contradictions.

    The way it works is, you pour developer only into one set of caps -- there's no way to get any chemicals on the negative since the negative isn't in the cap. Then you turn off the lights, unscrew the empty caps from the tubes and put the empty caps aside. Then you screw the tube with the negative inside vertically into the caps that contain the developer, so the cap is down and the tube is up, the assembly standing vertically on the bottom of the cap that has the developer in it. So still no developer has touched the negative.

    Once all six (or however many you are doing in this session) have been switched from empty caps to caps containing developer, you can turn on the lights. Then you grab all the tubes as a group and shake up and down vigorously to thoroughly wet the negatives in the tubes with the developer. Then you lay the tubes horizontally in the water tempering bath and start rotating the tubes. Somewhere in all that you start your timer of course.

    The scans you show indicate that you screwed the negative holding tube in a developer containing cap then laid the assembly down horizontally without rotating the tubes. This causes the developer to start working the part of the negative that's under the developer while the rest of the negative is dry. And that's what forms the line across the negative.

    The initial few seconds are the most important seconds in developing film. It is crucial that the entire negative be fully covered in developer as nearly instantly as possible. Even a few seconds difference can create artifacts like yours. I've even seen this with tray developing -- push the center of the film down to the bottom of the tray but some corner manages to stay above the developer in the tray just a second longer and you can see it in the finished negative.

    Bruce Watson

  7. #7

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    Re: Possible Uneven Processing with BTZS tubes

    Thank you, Bruce! I really thought what I said is what you said; perhaps, your explanation is more clear. It sounds to me like Mexipike is pouring the developer into a standing tube which contains the film. If you look, especially at the second example posted, I bet the right side of the negative was at the bottom of the tube and started developing before all tubes were filled and the shaking/rolling process begun. I don't think s/he understands that no developer chemistry touches the film until they are all picked up together, shaken, and rolled.
    Last edited by Alan9940; 26-Oct-2018 at 20:17.

  8. #8

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    Re: Possible Uneven Processing with BTZS tubes

    Thanks to both of you. I think that was my problem. I was filling the caps and then pouring them into the tubes rather than screwing the tubes into the cap. I just rewatched Fred Newman's video to get the exact right directions. That part is a little confusing in his video as it's when he turn the light out and kind of skips over it! Thanks for helping me to clarify.

  9. #9

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    Re: Possible Uneven Processing with BTZS tubes

    Quote Originally Posted by Mexipike View Post
    Thanks to both of you. I think that was my problem. I was filling the caps and then pouring them into the tubes rather than screwing the tubes into the cap. I just rewatched Fred Newman's video to get the exact right directions. That part is a little confusing in his video as it's when he turn the light out and kind of skips over it! Thanks for helping me to clarify.
    Whew, I'm glad you got it worked out. Prepare to enjoy very even development.

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