On 14 Mar 2004, at 10:45, Grafist@aol.com wrote:
> In a message dated 13/03/04 21:37:57 GMT Standard Time,
> richsul@earthlink.net writes:
> Do you think this makes the material porous in the same
> way as paper is porous?
>
Viewed under a scannin electron microscope, these coating materials look
a lot like paper, but they are actually made of polyethylene.
>So these holes act as a key to some kinds of coating?
> Maybe P.V.A.?
>
No, their function is mechanical -- they conduct the ink down to a dye
receiving layer through their pores.
> For some reason the newer pigment inkjet inks will not stick to gel
> coated paper so they've gone to this system.
>
> They were obviously looking for something that would
> hold more firmly onto the pigment ink.
I believe that the pigmented inks stick well enough; they just have a few
undesirable properties when applied that way. One is the differential gloss
caused by different pigments, which gives the print an odd appearance
when viewed from some angles; another is that the prints are flat matte and
good saturation is difficult to achieve. Another problem is that pigment inks
are subject to abrasion when they are exposed on the surface. And finally,
they dry slowly which causes all sorts of problems when inkjets try to lay
multiple dots of color over the same place.
The microporous coatings were developed in an effort to create glossy
papers that dried quickly and that were mechanically robust when dry. An
interesting paper on how they are manufactured and on how they work is
available on-line at the US Patent Office, paper # 06534123.
Sorry ... this is getting way OT. But it does *seem* that some of these
materials might be useful in some alt-processes, as long as the chemistry
in the dye-receiving layer is compatible, you want a glossy surface and/or a
transparent/translucent, flexible base, you can apply your chemistry
without dislodging material from the dye-receiving layer, the gods are
smiling, the phase of the moon is right, the ......
Regards,
Gary Nored
http://home.centurytel.net/Gary_Nored/
Received on Sun Mar 14 17:22:32 2004
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