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Hi I'm thinking of buying a set of Btzs tubes for B&W work only, has any one on the forum used them? If so, any advice would be greatfully recieved
Tony

Hi, Tony.
I have used the BTZS tubes for some time, and I like them very much.
They are not appropriate for developing a lot of negatives, but I amass six exposures over a period of time anyway.
The 60 mls of dev for each tube makes it reasonably economical, and temperatures seem to keep fairly stable because of the bath.
The continuous agitation requires adjustment of developing times, but I have never experienced any streaking or uneven development.
I find extraction of the negatives from the tube requires some toothed forceps if one is not to handle the negatives too much with one's fingers.
Viewing the negatives after extraction reveals some patches of light blue, presumably from contact of the negative base with the inside of the tube, but this disappears with washing.
With care and labelling of the tubes, it is possible to develop films of different speeds, removing the tubes with film of slower speeds, and allowing the remainder to continue to develop.
I think you will be very happy with the BTZS system.
Please get back to me if you have any other queries
John Fontana

Hi John thanks for the reply, regarding the reduced development times due to the agitation any information you have would be useful, Iv'e looked on the BTZS forum but there isn't great deal on it
Tony

Tony,
I like my negs fairly punchy. so do not reduce dev too much.
Typically I expose HP5+ at ASA 200 and FP4+ at ASA 64, developing them in 1:1 ID11 for 13 and 7 mins respectively. This is perhaps 15% less than in the case of intermittent agitation.
I've never done it but I suppose you could dev a series of three or more negs at different times and see which approximates to the sort of contrast you prefer. This is the beauty of the tubes as against tank processing.
hope this helps
John

John Fontana wrote:Tony,
I like my negs fairly punchy. so do not reduce dev too much.
Typically I expose HP5+ at ASA 200 and FP4+ at ASA 64, developing them in 1:1 ID11 for 13 and 7 mins respectively. This is perhaps 15% less than in the case of intermittent agitation.
I've never done it but I suppose you could dev a series of three or more negs at different times and see which approximates to the sort of contrast you prefer. This is the beauty of the tubes as against tank processing.
hope this helps
John

TA! fro the info
Tony

As far as I remember, Ilford recommend a 15% time reduction for continuous agitation processes.

One way of nailing the development times is to have a BTZS film test done care of the View Camera Store in the US - I use Acros mainly and now potentially have development times between roughly 4 1/2 mins and 15 mins depending upon subject contrast.

Andrew