BTZS tube question

[stradibarrius]

I just watched the video on how to use the BTZS tubes for 4x5 sheets. The presenter empties the developer at the time interval and without any caps on the tubes places them in the stop bath?

He makes the comment that he has never had a problem. I didn't think film was lightfast until it had been in the fix for a short period of time.

Does anyone else leave the tubes uncapped and place them in stop with the light on?

 

[KenS]

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Does anyone else leave the tubes uncapped and place them in stop with the light on?

Yes.. but, while my 'developer of choice' over the past few years has been Pyrocat HD, I have only a small 7 watt 'amber' safelight on at this step (the room light is extinguished before the tops are removed) and the tubes 'dropped' into plain water (with a litttle agitation) before going into the fix. This is the same technique I follow for the 8x10 tubes.

As yet, I have not noticed any 'fogging'... but I am pretty sure that any 'fogging' would only show if enough 'available' developer were available at a high enough concentration for more than the time before the film 'hits' the fix bath.

Ken

 

[Robert Hall]

Phil did this all the time. Film becomes less sensitive through the development process. While I wouldn't go shine a light down the tube, you should be ok.

Please note, I have not done this with my 12x20 film, just the 4x5.

 

[stradibarrius]

I did swap emails with Fred, the guy who made the video and he said that he has never had a problem. That he uses a smaller watt bulb, 75w, in the room while he is doing this. He also said when he teaches the BTZS class his studends always freak out but then see that it works out ok.

 

[Ronald Moravec]

Developer has induction time before it begins to work. water or acid SS should wash away the developer or neutralize it if SS, before the induction time has passed.

 

[Martin Aislabie]

I have inadvertently done a comparison test.

Two identical sheets of film (HP5 in ID11), (I always do a double take of each shot in case of mistakes)

One sheet accidentally flipped out of the carrier while in the developer.

When the carrier was lifted out of the Dev the detached sheet was left behind

After 30 sec in the stop and 60 sec in the Fix and I switch the room lights back on.

It might take me 15 sec or so to work out I am a sheet of film missing, which I retrieve from the Dev, a quick swish in the Stop and into the Fix

When comparing the two sheets of dried film on a light box, its easy to see the uneven development of the sheet of film which had floated up to the foaming surface of the developer.

However, the base fog of the two sheets is to my eyes almost indistinguishable.

I was amazed how unaffected the sheet of film was to a 100W bulb at 4~5 ft for all those seconds while it sat in the Developer.

Personally, I would not recommend switching the lights on until the film has been in the Fixer for a while but I can testify that it seems to make almost no difference

Martin

 

[frednewman]

Hi Barry - I'm always asked this question by photographers who have never used the BTZS tubes. I did the video to show that it works. You just have to quickly remove the cap and place the tube with the film in the stop bath and roll it around for at least 10 seconds. Yes I do use a 75 watt light while processing film with the BTZS tubes, it's my print viewing light. I was doing a film test during the video and with the BTZS film testing you are processing 5 sheets of film generally for the following times 4, 5.5, 8, 11, and 16 minutes. So the 4 minutes test is sitting in the stop bath until the 16 minute test is in the stop bath, so the 4 minute test is in the stop bath for about 12 minutes with the lights on. i've never seen fog on any of the negatives. Please note the BTZS tubes have been around for over 20 years.

You have to remember that Phil Davis was what I call a myth buster and just because you read it in a photography book doesn't necessarily make it true. He designed the BTZS tubes out of frustration of uneven development processing sheet film in a tray. All the products labeled BTZS were designed by Phil Davis to solve a problem.

If you have more questions you can always email or call me. Thanks for asking your question.

fred Newman