Mac Legrandi (juicebox@my-dejanews.com)
Sun, 14 Feb 1999 19:07:53 +0000
Hello!
I've saved all the various bleach formulas recently posted. I'm not a chemist and my main goal is to get good negs with the Lawless process. If other members of the list who have or have not tried the process using the strong R-21 bleach could let us know which of these "safer" formulas work.
I think this would be very helpful to all of us.
Thanks
Mac
-->Sandy, >Those bleaches are for (2) removing silver for reversal processing. Once the >sulphuric has converted the silver it gets washed out. > >For re-developing or toning (1) the silver needs to remain in a useable >form. The bleaches with hydrochloric acid do that as do others containing >(plain) salt. >This is one from Ilford, given for stain removal, but appears generally >useful as well as safe: > Pot permanganate 6g > Common salt 13g > Acetic acid, glacial 50ml > Water to 1l > >This can be thought of as: > Strong white vinegar 1 litrel > Salt 1tb > Pot permanganate (Condys crystals) 1tp > >Negs or prints left in soln with continuous rocking for abt twice as long as >required to bleach image. Wash until water no longer pink. Soak in 5% >metabusulphite soln until no brown permanganate stain remains. The image can >then be re-developed in a low sulphite developer or otherwise toned. > >I have not tried it. I appeals because it can be made up very safely, if the >glacial acetic acid is avoided by using the pre-diluted supermarket vinegar. >It should be handy for sulphur toning processes. > >I would be pleased to hear how it works from anyone who may care to try it. >It would be useful to build up a collection of modern, safe, formulations. > >Kevin O'Brien > > > > > >
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