Richard I remember on certain films we used a formalin bath to harden the very soft emulsion. As I recall, it was on some sheet films. This was in the 1940's. The darkroom smelled like a mortuary! Jerry Richard Knoppow wrote: > ----- Original Message ----- > From: "Allen Zak" <azak@xxxxxxxxxxxxxxx> > To: <rollei_list@xxxxxxxxxxxxx> > Sent: Friday, May 20, 2005 8:36 PM > Subject: [rollei_list] Re: OT: development > > > In 50 years of photography I have not once experienced > > emulsion damage > > from using non-hardening fixers. > > > > Allen Zak > > > I doubt if many if any current materials need hardener. > The standard hardening fixing baths like Kodak F-5 > (essentially the packaged Kodak fixer) originated in the > mid-1930s when emulsions were very soft compared to modern > materials. In fact, up to about 1939 the standard processing > temperature was 65F. It was raised to 68F after that because > some method of improving hardening was applied. I think we > use hardening fixer mostly because of tradition. > Auxilliary hardener is included in some color processes > which operate at very high temperatures and are necessary > for some special processes like monobaths, which are very > high in pH, but I agree that in general one could do without > hardener and suffer no consequences. > OTOH, if a wash aid is used the hardener does no harm and > may cause film to dry faster (less absorbed moisture due to > less swelling). > > --- > Richard Knoppow > Los Angeles, CA, USA > dickburk@xxxxxxxxxxxxx > > --- > Rollei List > > - Post to rollei_list@xxxxxxxxxxxxx > > - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' > in the subject field OR by logging into www.freelists.org > > - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with > 'unsubscribe' in the subject field OR by logging into www.freelists.org > > - Online, searchable archives are available at > //www.freelists.org/archives/rollei_list --- Rollei List - Post to rollei_list@xxxxxxxxxxxxx - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' in the subject field OR by logging into www.freelists.org - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field OR by logging into www.freelists.org - Online, searchable archives are available at //www.freelists.org/archives/rollei_list