Digital BW, The Print

Paul Roark wrote:





> A couple of issues I'm wondering about are, first, whether the apparent
> stacking of the dye molecules is before they hit the paper or whether they
> have found a way to get them to form larger crystals on the paper itself.
> The size of the final, dried particle is what distinguishes the "dyes" from
> the "pigments" in terms of longevity.  However, if the stacking is after
> hitting the paper, the ink would spread or bleed like a dye -- not a good
> thing for sharpness.  So, I'm assuming the stacking of the dye is done
> before it's printed.  

Both pigment and dye ink can print sharp, enough ingredients 
to create a better rheology in the inkjet ink and on the 
paper. Though not all papers are tested by Wilhelm I get the 
impression that the ink isn't so coating dependent for good 
fade results which points to being stacked dye from the 
beginning. But a Kitamura has been involved in two component 
inkjet inks, the last doesn't have to mean that one component 
has to be in the paper coating.
http://www.freepatentsonline.com/20060028521.html
> 
> I'm no chemist, but another question is where the line is between soluble
> and non-soluble.  How many molecules could they stack before this "dye" is
> really just a pigment with such small particles that they simply will never
> settle?  Given the apparent pigment-like resistance to bleeding, I'm
> guessing this new "dye" is, in fact, a super-fine pigment that Epson for
> some reason finds advantageous to call a "dye."  

The line below the molecule structure pictures says:  Epson\ufffds 
newly developed Claria ink is much more resistant to light and 
ozone thanks to its tightly clustered pigment molecules.

The dividing line between dye and pigment isn't drawn by Epson 
either.

> Have you noticed that the Claria inks do "worse" with UV filtering in
> Wilhelm tests?  The explanation appears to be that one or more of the colors
> is disproportionately affected by UV.  As such, the filter makes one of them
> so much better that, while the fade rate decreases with UV filtering, the
> color balance shift gets worse and triggers the end point definition sooner
> than the fade rate does.

My bet is on the yellow. The cyan shows good properties in 
both old dye and Claria. The improvement has been exceptional 
in yellow and they indicate the yellow is a lot more vivid. 
Yellow is usually the most affected by UV, if they improved 
its light + UV resistance that much it could show a shift to 
yellow when a UV filter is used, there are more components 
(paper) in a tested print that shift to yellow already.

> As much as I'm curios about the inks, like John indicated, I'm really much
> more excited by 1.5 pl, 5 dot levels, and a modern 13" platform for less
> than $400.  I also expect this head will find its way into large format
> printers.
> 
> It's definitely going to be fun to see Epson, Canon and HP duke it out.

On wide formats you do not use 1.5 pl, think 3 or 4 pl for 
that market, Epson already has a problem to get equal in speed 
to HP and Canon with their thermo head assemblies that have 
12K or 25K nozzles where Epson has 1.5K nozzles. One of the 
reasons why Epson made that black inkline shift on the 3800 is 
that they want to keep head number low, a pi\ufffdzohead is far 
more expensive than the new thermo heads are (nozzles 
counted). So I expect that Epson will not be the champion of 
multi color heads but will try to improve ink technology to 
get similar results with less inks. The step from UC to K3 
showed an improved M and C transparency (Yellow has always 
been more transparent) and Claria is another step towards more 
dye like (transparency) behaviour. I don't think they will use 
it for the wide formats though, the market is different and K3 
suits it well right now. It will be interesting to see gamuts 
of Claria and the 3 pigment ink samples of E,HP, C, next to 
one another. Gamut size could be equal but with differences in 
the shape, transparency should create better shadow color, 
primary mixes will be better on N-color printers.

Met vriendelijke groeten,Ernst


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