BTZS tubes

I have what I guess is an exceedingly dumb question... I was watching this video about the BTZS tubes for developing 4x5 film:

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He takes the cap off of the tube when development is complete, and puts the open tube into the stop bath... I thought that the film had to be fixed before it could be exposed to daylight... In fact, I was so reluctant to ask this question here that I looked in an old B/W book that I have. The book seems to indicate that it isn't safe to expose the film to daylight until after it has been fixed, but that doesn't seem to be what this guy is doing.

Also, does anyone have comments about this system? I am using a CombiPlan tank right now for developing, but this looks easier/better.

The video need light so you can see what's happening but you do this in the dark

I've used tubes for 10x8 but there's no way I'd do this for 5x4 as I much prefer a daylight tank & use Jobo's and a Yanke (similar to a CombiPlan). However for an odd sheet needing N+2 N-2 processing I use a normal 35mm/120 tank without a spiral (still with the centre column though).

Ian

Yes the film is exposed to the light after developing, but directly into stop. The development has ceased. As long as the film does not go back in to the developer the re-exposed silver will not be on the negative after fixing. Some will argue that some silver halides will covert to elemental silver. While possible many have used this process without ill effects. I sue this for most B&W 4x5 I do especially when I have different development times. Vener get a scratch or shuffle out a sheet at the wrong time as the tube are labeled with times. ( Processing note: I place a piece of masking tape on the film holder when shot with dev. notes on it. Then when loading the tube the tape is transfered to the tube at the same time as the film. )

My biggest complaint with this processing is it does require an acid stop, the developer cannot be allowed to carry over as might happen with a water stop. I prefer an all alkaline development. I sometimes go strait form developer to the fix in some cases knowing that the fix will be tossed at the end of the session.

This very issue have been discussed in length quite recently. Make a search on "BTZS" and you will find plenty of info on the subject, apart from everyones opinion .
I remember the old instructions, which was a series of pictures. Back then they said that "subdued light" was OK. With that in mind I once tried to "speed things up" when working with a CombiPlan, so instead of draining and filling the tank in the ordinary way, I just opened the tank in my red darkroom light, ripped the lid off and changed fluids with no problems at all. (Today I mostly use Jobo tanks. )
Shorter version: Don't shine a flashlight into the tube and you're allright.

//Björn

It's still better to just do it in the dark. Some developers are far better at desensitizing film than others and you are just adding an unnecessary risk if your not using one of these.

No serious publications advocate this method, and its far riskier with modern film. Development by inspection requires the right sort of subdued lighting usually a fairly specific safe-light.

So you could be lucky or you might just ruin some important negatives.

Ian

as noted, this has been discussed many times and recently as well.

There is no problem doing this process. I leave my amber safelight on and put the opened tubes with developer dumped into a tray of stopbath, sometimes for as long as 10 minutes, while the rest of the tubes finish processing. There is no increase in B+F. None. Ever. Just try it and see. It only takes a couple sheets of film to confirm.

jeroldharter said:

as noted, this has been discussed many times and recently as well.

There is no problem doing this process. I leave my amber safelight on and put the opened tubes with developer dumped into a tray of stopbath, sometimes for as long as 10 minutes, while the rest of the tubes finish processing. There is no increase in B+F. None. Ever. Just try it and see. It only takes a couple sheets of film to confirm.

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Ditto to what Jerold has said. BTZS processing really produces some high quality negatives.

A bit of a thread resurrection here, but I wonder if someone can answer some questions re: BTZS processing. I generally use a CombiPlan for processing 4x5 sheets and I have no problems with it, except that it really is not terribly economical from the chemistry standpoint if you are only doing 1 or 2 sheets. I brought a raft of exposed sheets back from a vacation recently, so the Combi was fine.

However, I'm still very much a LF beginner, and often would like to focus on a shot with only one or two exposures to really try to understand what I'm doing, both right and wrong, and something like BTZS seems more logical.

So now the questions. I watched the video and I'm wondering just what is the inside diameter of these tubes, and how much chemistry does the cap hold? Also, as I understand it, because the amount of chemistry is so minimal, you are essentially doing constant agitation, correct? Do the usual development times apply for the type of developer used along with the temp. or is there some modification you have to make for the kind of agitation going on in the tubes?

Don't know the diameter but the inner circumference is just >4 inches so that the film is inserted in vertical orientation.

The cap holds 80ml of developer.

Yes, it is constant agitation. Dilute, one shot developers work best.

Most films include data for "rotary" processing which is a good starting point for use with BTZS tubes. Also, BTZS has published developing times for different developer/film/temperature combinations which are good starting points. The idea is that you would eventually do your own testing. If you have a Stouffer step wedge you can use it to process film in your conditions ad various processing times (e.g. 4, 5.6, 8, 11, and 16 minutes) and then send the film to the View Camera Store for sensitometry and they will do all of the BTZS stuff for you and return spreadsheets with film speed, development times for N+/- development, etc. It costs ~$50 for the test which is well worth it. However, you can pick up a used densitometer for ~$100 and do as much testing as you want. For example, my normal development time in BTZS tubes for TMY-2 film in Xtol developer diluted 1:1 at 68 degrees is 7:56 and the effective film speed is 400.

Thanks for the quick reply. The rotary processing makes sense, should have thought of that. They sound like a good option for the intended use I have in mind.

The inside diameter of the tubes is 35 or 36mm. The caps (at least in the current generation of 4x5 tubes) are best used with 60ml of developer, which is what the instructions recommend. You could squeeze more in if you wanted, but you would likely over-develop the leading edge of the film as a result...

Ian

iandavid said:

...are best used with 60ml of developer, which is what the instructions recommend. ...
Ian

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Oops. I think 60 ml is correct. I have been using the 8x10 tubes lately which is 8 oz. I think I confused that for the 80 ml for 4x5 tubes. Thanks for the correction. The 60 ml = 2 oz so that makes sense.

Interesting, that 36mm for the inside diameter. That's a bit less the 1.5 inches. The tubes looked to have a greater diameter than that when he held them in the video. Thanks for the correction on the developer volume also.

Hi csb999 - You have to understand that Phil Davis was a myth buster. Yes it does work in the light. In the video and when using the BTZS tubes I uses a 75 watt bulb, which is my print viewing light when processing film. For some reason I never questioned if it would work - I just tried it. I figured what would be the worst thing to happen - I would ruin a few sheets of film - but it worked. At all the BTZS workshops the students are usually skeptical but once they try it and it works they now have a new procedure for processing film. You just have to do it quickly like in the video. Also you don't want to use florescent lights.

Fred Newman