Hi Gang,

Wondering if anyone has a "chemistry" idea as to why I am getting some weird staining on the acetate side of 4x4 HP5 film. I am devloping in BTZS tubes, using both D76 1:1 and Rodinal 1:25. On the acetate side of the develoepd, fixed and washed film is "gloppy" patterns of milky streaking.. No amount of fresh fixer or permawash will clear this mung from the film base. Heck, I have left the film in fixer overnight! by teh way, fixing is in Kodak Hardening Fixer...

The areas of discloration or most prevalent along the centerline of the sheet where the midline is pressed tighest against the tube wall and no circulation around the back of the film can occur. In the case of Kodak films, this effect always is taken care of in the fix and wahs process.... however, for HP5, the problem will not "wash away".....nor will it "scrub off" when the film is wet...

Given the "durablity" of this milky staining, I am wondering if there is a chemical reaction occuring between the film base and devloper in the case of HP5 that simply is not occuring consistently, hence the mottled milky streaks...

Anyone else seen this problem? I can find no similar issues on photo.net..

Thanks, MEC

-- Michael Carboy (mcarboy@pacbell.net), July 15, 2001

Answers

Phil Davis recommends removing the film from the tubes and finishing the hypo-clear /wash in trays, to allow better circulation of chemistry to the film back. Are you doing this? He also states that two or three cycles of hypo-clear and wash are sometimes necessary to remove all the anti-halation dye.

-- Henry Friedman (friedlew@worldnet.att.net), July 15, 2001.

I think the problem is that solutions simply aren't getting to the base side of the film. I don't know exactly what's on the base side, but presumedly it's an antihalation dye, anti-scratch coating etc.

The only time I've seen anything remotely similar with HP5+ was when I tried to develop sheet film in a Jobo print drum...which also doesn't allow much flow to the base side.

-- John Hicks (jbh@magicnet.net), July 16, 2001.

BTW, you really should ask Fred Newman, info@darkroom-innovations.com

-- John Hicks (jbh@magicnet.net), July 16, 2001.

I'm not a chemistry expert, but I do develop a lot of HP5 in tubes.

I don't have staining problems with this film. I use Ilfosol developer, acetic acid stop bath, Ilford fixer with no hardener. For what all of this is worth...

The dev, stop, and first of two fixers is in tubes, then I transfer to 4x5 trays for the final fix and wash.

I _do_ have a problem with the anti-halation layer of TMX in the same configuration. It's not milky, but a cyan-ish blob stain near the centerline of the sheet. Since there is plenty of access to the back of the film in the fix, I guessed it was normally removed in the developing stage. I have found that soaking about 5 minutes in a sodium carbonate solution after fixing removes it. I've occasionally used the developer again (after fixing!) and that does a pretty good job too. No concentration suggestion for the carbonate. I just kind of throw a handful into about a liter of water and mix.

-- mike rosenlof (mike_rosenlof@yahoo.com), July 16, 2001.