Pyro after-bath

About this list Date view Thread view Subject view Author view

From: Victor Loverro (victor.loverro@verizon.net)
Date: 09/20/02-01:16:10 AM Z


Please forgive the long post.
There has been some discussion on this news group and others regarding the effectiveness (or lack of same) of placing Pyro-developed film back into the used developer after it has been fixed. The consensus seems to be that there is no advantage to increase stain proportionately, but that the afterbath only adds overall stain evenly. What follows are the results of some preliminary tests done with FP4 and TriX only.
  The parameters: I developed the film in a Jobo CPP2 using Rollo Pyro. Density reading were taken with an old MacBeth TD504 with the blue channel. Film exposures were not made in a lab-controlled environment, but duplicate shots were made on days of consistent bright overcast lighting. I understand that sodium metaborate may be used in place of the used developer with the advantage that it is less likely to increase B+F.
My results for FP4:
  With sodium metaborate as an afterbath I found no increase in density at all, not even at relatively high maximum densities, such as in one case, 1.65. The films both with and without the after bath had exactly the same densities.
  For identically exposed films where one is placed into used developer after fixing I found some proportionate increase in density. The B+F was the same for both films and up to about .80 they were about the same. At about 1.00 the film from the afterbath had about .04 higher density and at about 1.35 it had about .08 higher density. So there seemed to be some proportionate increase in density using the developer for an afterbath, but not so much as to be worth the trouble. The same increase would probably result from slightly longer developing times.
My results for TriX:
  I made three identical exposures and the film was developed to a higher density (to be used for POP). One film was placed in sodium metaborate and here the B+F was identical to the film that received no afterbath. Again there was some proportionate increase in density but the highest (at densities around 2.00) was only about .08. Again hardly worth the trouble of the afterbath.
  However, for the film placed in used developer as a afterbath, the B+F showed an increase of 0.12 and this same increase was added evenly throughout the range of densities up to 2.00. So in this case, there definitely was no advantage to using the developer as an afterbath.
  All films received a long final rinse (20-30 minutes). For me, the FP4 only acquires the stain color after a long rinse.

  In an article by Maxim M. Muir, "Pyro Tips and Tricks", he mentions the possibility of more effectively increasing stain by using sodium carbonate rather than sodium metaborate or used developer. Has anyone tried this? I wonder, with the reputation that T-max 100 has for not staining well, whether this might work better on this film. Considering this film's advantage for less reciprocity failure at long exposures, and the fact that it is available in ReadyLoad, it would be nice if it responded better to Pyro development. Has anyone tried sodium carbonate as an afterbath for any film?
Victor Loverro

  


About this list Date view Thread view Subject view Author view

This archive was generated by hypermail 2.1.5 : 10/01/02-03:47:09 PM Z CST