Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Paul Roark" <paul.roark@v...> wrote:
> >Don't leave the "Glop" sat in your printer for along period unused, 
> >some types can react and cause the ink to dry out and solidify in 
> >the cartridge particularly if it is acrylic or urethane based. 
> 
> Thanks for the warning.  I had a similar feeling and pulled it out as soon
> as the experiment was done.  I use a C86 for testing.  It's a lot cheaper to
> wreck one of these than the alternatives.
> 
> Glop is, of course, meant to be used in a printer, at least by itself.  I've
> tried to inquire about clogging, but have found no evidence yet that it
> clogs more than other inks.  This is an issue to keep an eye on, however.

By itself, I'd expect it to be relatively stable, just like any lacquer stored for a period of months or years.

But contaminated (even lightly contaminated) and all bets are off.

My parents house has what looks like 2 foot tall chunks of amber in front of it. My dad brought them home from work one day. They were the result of a tank of resin (he used to work at Rinchead-Mason, a big automotive paint manufacturer) that got contaminated and catalyzed into solid material in the tank.
 
> >We did a 3year test on several versions of this type of combination.
> 
> Is it just the combination with other inks that is the problem, or does glop
> by its nature tend to solidify?  

I'd say, if it's kept clean, it should stay liquid for years. If you're mixing it with inks, that could be considered "contamination". Also if you're loading it into non-virgin carts.
 
> Frankly, the bulk glop looks most like the UT base.  When it is printed by
> itself, it does have a bit of density to it.  So, it's clearly not just
> base.  I think I've read the Epson version is an acrylic suspension.
> Water-borne acrylic sprays, like aerosols, seem to have a bad reputation for
> clogging those nozzles.

The Epson version is a suspension of whatever is used to encapsulate the pigments in ultrachrome. So it shouldn't be any more troublesome that any colored Epson pigment.

Grind something fine enough, and it can stay in colloidal suspension forever.

> A paint technician once described water-borne acrylics as being like gooey
> little golf balls suspended in water.  I have assumed that the acrylic that
> Epson uses is relatively solid, but, on the other hand, it is used around
> their pigments to help hold them onto the paper.  

I thought it was used to help longevity.
 
> Do you know how these Epson acrylic coatings and balls that are supposedly
> used in the R800 glop compare to the acrylics that are in coatings, for
> example the Golden mediums we were experimenting with for coating finished
> prints?

The water based versions use balls that are much bigger than the Epson ones. They won't stay in colloidal suspension, and form thixatropic slurrys.

To make something sprayable in a printer, the colloid has to be so fine that even under pressure, or local high differential velocities and shear, it stays a colloid. Thixatropy will clog the jets.

The solvent based coating don't have particles at all (except insoluble contaminants). The actual coating is fully in solution.

Wow, looking at this site and at dpReview, I've now got hundreds of people, some of them quite respectable print makers and scientists,  saying "glop".

;) ;)