View Full Version : BTZS and Ilfosol 3

20-Jan-2017, 10:29
I've been using Ilford FP4+ (4x5) and Ilfosol 3 @ 1:9 in BTZS tubes as a starting point to learn developing. The developing times are fairly short (less than 4 min if you adjust for continuous agitation according to Ilford) and I wanted to extend the developing time by increasing the dilution to 1:14.

The Ilford spec sheet for Ilfosol 3 says 500 ml will develop 24 135/36 rolls at 1:14 which I believe works out to 96 4x5 sheets. That means each sheet requires 5.2 ml of developer. The BTZS cap only holds 60 ml of solution and at 1:14 would only contain 4 ml of developer (Massive Dev Chart).

That suggests there's not enough developer in the tube do 1:14. Can anyone confirm this? I can run some test negatives but I'd rather not waste the time and money if it's a non-starter.

Thanks for any help you can give me


20-Jan-2017, 17:03
You could measure 5 ml developer and 70 ml water into a measuring cup, load the film in darkness into the tube, pour the developer into the tube, cap the tube then agitate as normal. This gets you the right amount of developer and avoids the limitation of the cap volume.

I do a version of this procedure with 270-300 ml of total solution in a BTZS tube using stand development. I add a rubber tube extension sleeve with threaded cap, which allows the use of that much solution, thereby guaranteeing that all of the film surface is immersed in solution. The brimful volume of the tube is something around 250ml or a bit more.

20-Jan-2017, 19:08
That's a good point and an interesting idea. What did you end up using for the rubber sleeve?

Thanks for getting back to me


20-Jan-2017, 20:21
I use a Fernco rubber pipe coupler. I think 1-1/2". I brought the BTZS tube with me to the hardware store. http://www.supplyhouse.com/Fernco-1056-150-1-1-2-x-1-1-2-Flexible-Coupling-Cast-Iron-or-PVC-to-Cast-Iron-or-PVC?gclid=Cj0KEQiAh4fEBRCZhriIjLfArrQBEiQArzzDAUIwdJcdX-pKLUc316_ikLOExtvTVVcAMt2eeDwavBwaAtYJ8P8HAQ

Then a male threaded reducer is used to adapt the rubber coupling to a cap, something like this: http://www.homedepot.com/p/Charlotte-Pipe-1-1-2-in-x-1-1-4-in-PVC-Sch-40-MPT-x-S-Reducer-Male-Adapter-PVC-02110-1200HD/203825624

Finally, a threaded cap is needed to seal the tube, something like this: http://www.homedepot.com/p/Charlotte-Pipe-1-1-2-in-PVC-Sch-40-FPT-Cap-PVC021171600HD/203811726

20-Jan-2017, 21:17
great idea - thanks for sharing