A short history lesson regarding the C80 printer might help to explain
some of this situation. The Epson C80 was the first 4 color Durabrite
Pigment ink printer Epson released. AT the time, their plan was to
promote this printer as an office printer, not a home , graphic or photo
printer. They basically wanted it to compete with black and white laser
printers that had the extra feature of allowing for spot color in
business documents. On of the main things Epson was pushing was the
speed of printing for black only documents. They claimed it could print
as fast or faster than some mono laser printers, and provide both the
quality on plain paper and the permanence of laser.
In order to make the ink dry fast enough, Epson had to reformulate the
Durabrite black ink (although the C80 was the first Durabrite 4 color
printer, it was not the first Durabrite ink printer, which was the 6
color 2000P). For the C80, they removed the resin from the black
pigment ink, because the resin required much more glycol be added to the
ink, to slow the drying (so the heads wouldn't clog). This made the ink
very fast drying on plain paper. This same ink also was fine on matte
paper, where the ink could be absorbed into the paper substrate. The
problem was with glossy paper. While the C M Y inks all had resin in
them that allowed the pigment ink to bond to the paper surface, the
black didn't, so it could not be used with glossy paper. The original
C80 drivers could print a photo-like image, but it only used CMY without
black, and the results lacked contrast.
SOme people who bought the printer weren't very happy. They basically
could not make full tonal range color images on glossy paper. If they
tricked the printer by setting it to matte paper and printing on glossy
anyway, the black ink would literally rub right off the surface, even
after drying.
So, Epson developed a new paper that allowed the ink to be absorbed into
the surface, for the black ink to hold on, and they offered a patch to
the driver to allow for this change in ink functionality.
In later C/Durabrite printers, Epson put the resin back into the black
ink, realizing their market was still photographic color images
printing, for which people wanted color glossy images.
Now, why one package says C80 and the other does not... there are
several possibilities. I honestly don't know which of these are true.
1) the paper may not be the same, or someone forgot to write the C80 on
the list on smaller size.
2) the paper may have been manufactured at different times, or in
different factories and it may have been considered either more or less
important at the time it was made.
3) Epson may have changed the black ink for the C80 by now, and it may
now contain resin in which case, it will work on all the Epson Durabrite
Ink glossy papers.
4) The 4x6 paper will not work with the C80 ink set with all four
colors, because the black in was not changed.
So, I cannot answer your question, but I can give you some of the
history as to why this is a bit of a mess.
Art
