I only use chrome gelatin for decalcified bone sections IF the plus
charge (Silane coated) slides DO NOT work.  You can make it up with
different bloom gelatins (bloom indicating size of gelatin molecule
100 small, 275 and 300 large).  The reason I do not care for gelatin,
is background staining with hematoxylin, can be reduced by dipping
presubbed slides in NBF 10 dips, rinsing well and storing in cool
dry box.

5gm gelatin in 1 liter distilled water, add 1 gm
chromium potassium sulfate, dip clean slides in this,
air dry and store.  Use these slides like regular, you do not
need anything in waterbath.

OR

Add 10 mls of this stock to a 2 liter waterbath, like adding adhesives
to a waterbath, dry sections in normal way - I dry bone slides flat
at 37-40C for a couple of days, overnight is minimal.  Soft tissues
can be dried in an oven.

Chromium is considered very toxic, so use precautions when preparing
the subbing solution.  I preferred the waterbath method when doing a
large number of blocks.
I never use subbing for soft tissues or sections for immunostaining.
It was my backup when all else failed to keep sections on the slide.

Gayle Calis