Try _without_ the pre-soak. Atleast Ilford recommends not to presoak
because of anti-foaming coatings. Try without pre-soak and maybe you'll get
rid of the bubbles - and a useless step in processing :)

Severi S.

I have had the same problem in the past when I worked for a guy that had
Paterson equipment (could not load a ss reel to save his life).  No amount
of inversion ever eliminated the problem.
And I broke a couple of tanks trying to bang them hard enough to dislodge
the bubbles.

Then when cleaning the pit he called a darkroom one day I found one of the
little agitator rods that twist the reels back and forth.

I put a piece of rubber tubing over the end of the "swizzle stick" to give
me a better grip and started twisting the reels in the tank.  30 seconds
continuous at the start of the cycle and 5 seconds every 30 after that.  The
bubbles went away.

--
darkroommike

----------

I've been using for deacades a Jobo plastic tank and never (well, almost)
had bublle problems.

Just a guess:
I invert and twist the tank at the same time.

Jorge

aldenphoto@aol.com (Ken Smith) wrote in news:eb5d68c1.0402061032.52fb5bf2
@posting.google.com:

No system is perfect. However, I prefer Metal Reels and Tanks.  The more
experienced photographer gurus that use Metal Reels & Tanks will still get an
occasional bubble every now and then.

Shaking the developing tank like a milk shake will obviously create new bubbles.

Are you filling the tank up to the top?  I find that is a good way to avoid
bubbles as well.

Plastic reels are thicker than metal reels and the result of this is, more air
is trapped under the outer rims of the plastic reels.  I also noticed that I was
getting more bubbles and thinner densities on the outer edges of my developed
films in plastic reels.  Dry plastic in my opinion likes to catch bubbles.
Also, the thickness & width of the outer rim of the plastic reels also
contribute to the catching of bubbles.  Not to mention that the developer
doesn't get under the plastic tracks of the film reels to give even development.
Plastic seems to dry immediately when a bubble makes contact with it. Which is
why wrapping the tank hard on a flat surface is critical to getting the bubbles
loose from the film.

Because the Jobo system offers continues movement they get better results then
manual systems.  Jobo also has a problem with sprocket hole Dev-flow marks
because of the constant movement of the development tank.

Plastic Reels may be easier to load than metal reels but metal reels are thinner
and if used correctly, offer better results than plastic reels.

Also; Metal Tanks offer better temperature control than plastic tanks do.
Especially when you are talking about short development times of 4 & 5 minutes.
Plastic doesn't conduct temperature quite like metal does and the temperature
control is more difficult with plastic Tanks.

I am a big proponent of Metal Reels and Tanks for the aforementioned reasons.

I use JOBO tanks and reels - no prewet - solid bang on table with 4mm
cardboard to protect plastic after every group of agitations -  don't get
air bubbles on 120 or 35mm film.  When I agitate I hold the tank at the top
and bottom with both hands and quickly swing it in an arc from waist hight
to face height to other waist height fairly quickly and can feel the liquid
moving.  I leave a space above the liquid of about 1-1.5cm so the liquid can
move.

Note one poster seems to be talking about JOBO motor driven tank rotation
when they talk about sprocket hole streaks.

regards
       Malcolm

Air bubble marks I have seen have all been round - exactly what shape are
the ones you are getting - also are they in from trhe edge or only where the
film sits in the groove?  if they are irregular shapes perhaps there is some
deposit on the reels effecting development at the edges.