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  1. #21

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    With most traditional films, complete fix happens in 2 minutes time if using a Rapid Fixer. Double that and some with traditional fixer. Tmax will take double that. Either way, it's pretty quick.

    Since OP is using 35mm format, unrolling the film to inspect is basically really not an option, not to mention seeing if there are problems with wet film isn't easy either unless the problem is severe.

    It's far easier and practical to switch to rapid fixer if not already and do the complete processing.
    Develop, stop, fix.... wait.... where's my film?

  2. #22
    Bill Burk's Avatar
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    Quote Originally Posted by pentaxuser View Post
    I am confused again Bill. Are you saying that BTZS tubes allow the very thing that I had concluded was impossible based on your explanation, namely the ability to examine negs after developer under a 40 watt bulb and then presumably to safely increase development if required?

    Thanks

    pentaxuser
    Sorry if it's confusing. No, the idea is not to do inspection and possibly continue.

    The idea of the BTZS tubes is to develop for the allotted time, open them up and roll them in the stop bath tray - then in the fix. It's only "incidental" light that gets into the tubes because you opened them up at the end of development, while working comfortably under the light of a 40 watt bulb. You should leave the film in the tubes until you take them out to wash. The less handling the better, fewer chances of scratching. The design is simple, the tubes don't need light baffles. Each sheet of film gets its own tube, so processing is very even.

    The hypothesis is: With acid stop and acid fix, processing stops immediately, so even though you exposed the film, you don't develop it any further so there is no measurable effect. The challenge to the hypothesis is: With neutral stop and alkaline fix (a popular combination these days), development of the (now) exposed film continues and the effect might be measurable. It's not likely to be serious, but you never know until you try.

    The design is brilliant. You get even processing and few scratches... the holy grail of sheet film processing...

  3. #23

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    Thanks Bill, I now understand. In effect the BTZS tubes do what Roger hicks calls the "Ilford Trick" which is that when Ilford demonstrated film processing the demonstrator used to remove the film from the developer in full roomlight and plunge into fix in what appeared to be a casual manner without ill effects.

    Apparently the "trick" relies on speed in that there is a very short period in which the light fails to affect the film between dev and fix, so not really as casual as it appeared to the audience. Roger gives a better explanation but this in essence is or was the trick. I say "was" as Ilford may not have demonstrated this since the days when film was all there was to record pictures. Must have appeared pretty spectacular

    pentaxuser

  4. #24
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    I just don't see why, unless you're shooting LF. And its still hard with a green light and you only can take a very quick look at the most.
    - Derek
    [ Insert meaningless camera listing here ]

  5. #25
    Bill Burk's Avatar
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    Oh it affects the film alright, it's still very sensitive to light... It's just that, you know, it took several minutes to develop this far... and you sure aren't developing even one more minute. So you don't ruin the negative that developed so far as a result.

    But like a tree being cut down, the film is screaming when you turn on the light, even if you can't hear it.

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