That has been my experience too. And if it only expired a year ago, I
wouldn't think film age to have any bearing anyway. I've had 800iso colour
film that had been expired for 5 years, and had been exposed to fair heat (i
found it under the car seat - it'd been there for at least 5 years) that
still worked ok, except there was a fair amount of base fog (still quite
printable though). I regularly buy expired film cos it is cheap :-D and have
never had any issues.

I don't use Kodak B&W film other than P3200, and I don't use Xtol, but I
vaguely recall something about Kodak changing some of their emulsions, such
that the new emulsions require less development time than the old
emulsions - perhaps you dev'd an old emulsion at the new times??

The

  Yup, I've had the same experience with brand new 100T-Max. It was
the developer. This was fresh bought Xtol mixed about three weeks
before use and not used until then. I diluted it 1:1 and found the
negatives very thin. I then tested the developer with a scrap of old
T-Max from a bulk loader and compared the scrap to another off the same
roll tested in D-76 1:1. The difference in density was great, about 2.0
for the daylight fogged clip in Xtol 1:1 and nearly 3.0 in the D-76
1:1.  I don't know what happened to the developer. I talked to Kodak
but I had none of the powder left and had thrown away the Xtol package
so didn't have the lot number. They sent me a replacement package but
could not explain what had happened to the developer. I use tap water
for mixing and diluting but have not had problems with it in the
fifteen years that I have been working at this location.
   Also, I recently tested three rolls of very old film. Each of these
had expired about ten years ago or more. They were Verichrome Pan,
Ilford HP-5+, and Ilford FP-4+. All had spent at least part of the time
in the refrigerator. The HP-5 came out fine. Perhaps a little foggy but
ISO-400 films are generally a little foggier than ISO-100 films. The
Verichrome Pan was probably around fifteen years old. It worked OK but
was rather foggy. The FP-4+ had almost no fog but had some mottling
beginning about half way along the roll. I suspect this was from
moisture condensing on the emulsion at some point. All these films were
120.
  I suspect your thin negatives are from the developer. If you can
obtain clips of some any film run a test in the Xtol and some other
developer. Develope for what ever is normal for the film. See how much
difference there is in density. While I have a simple densitometer you
don't need one. The difference in my two test clips was very obvious to
the eye.
   As a rule old film gets foggy but doesn't loose sensitivity or
contrast. Most modern films are very stable and have very long shelf
life if kept from very high temperatures.
   If you determine the developer is at fauld call Kodak customer
service at 1 800 42 2424 and ask for extension 19 (professional
service).

Richard Knoppow
Los Angeles, CA, USA
dickburk@ix.netcom.com

I suspect a single year expiration is not the cause. If the base is
clear and not grey you may as well discount that the film has aging
problems. Did you shoot the films at the same time and forget to rate
the 100 for 100 asa? Did you rate the 100 speed film at about half its
normal asa?