I waited  3 days to two weeks after printing before mounting.  I use Epson
Premium Glossy paper (is that "swellable"?), Epson ink.  (I never had
significant problems with scratching using Epson inks, only with MediaStreet
ink.)  I always frame immediately after cleaning the glass with Glass Plus
or Windex.  I don't let the heat press touch the photo when drying (4 min.
at 190 deg.) so there is room for moisture to escape.  I do that step with
dry mount under the photo.  After drying I then immediately press.  I use
acid-free dry mount, also press for 4 min. at 190 deg.  (longer and hotter
than manufacturer-reccommended, but it just did not adhere with less.  I
still get occasional bubbling months later.)

The pattern of fogging on the glass suggests it isn't just fumes from the
photo coming off: They would be relatively uniform in the space between the
photo and the glass (created by 4-ply mat), and certainly not in the bizarre
patterns I saw (vertical fuzzy bars about every inch and "brain surface"
pattern, with "sulci" a few millimeters apart).  I suspect now that, even
though I let the cleaner dry "completely," any invisible residue could have
dried by contracting to a pattern, like crystals.  At that point, the
fogging could be either from the cleaner alone, or from the photo.  If the
latter, it deposits preferentially on the surface where there is cleaner
residue.  So maybe everyone was right.  My training is as a scientist, so
maybe I'll do a controlled experiment (e.g., clean only half the glass just
before framing, use fresh vs. aged photos, etc.)

--
- Alan Justice