Digital BW, The Print

FWIW, the 7800 LK appears easy to make by diluting the Epson 7800 PK with the generic base at a 1:1 mix ratio.

I was surprised that the PK to LK step was 1:1 as opposed to closer to 30% PK.  I did not make an LLK dilution, which, again, is typically 30-33% LK, remainder clear base.

The Epson 7800 PK and LK are more neutral than the MIS glossy carbon, but the Epson "gray" inks also appear to be blends that are more than just carbon pigments.  The Epson MSDS for the ink says the PK has less than 3% carbon black and less than 5% "proprietary dyes and pigments."

It would not nice if it were carbon only, but it appears not to be the case.  Wilhelm makes reference to the "carbon based" black inks, but it appears carbon may not even be the primary pigment. 

Paul
www.PaulRoark.com

On 04/27/2012 03:42 AM, Paul wrote:

> I was surprised that the PK to LK step was 1:1 as opposed to closer to
> 30% PK. I did not make an LLK dilution, which, again, is typically
> 30-33% LK, remainder clear base.

If you compared it to diluting HP PK, I always had the impression that 
the HP PK and the other Vivera greys are quite dense compared to other 
ink set grey inks. One of the reasons could be that the substitution of 
CMY grey mixes with a heavier grey etc reduces ink lay down more. There 
has to be a balance what is visually acceptable and best for the paper 
coating but the Z3100 in total has hardly any composite greys in color 
prints left and its droplets vary between 4 and 6 picoliter. Drying time 
is fast, color stabilises fast and that is also desired for the internal 
calibration + profiling if done in one run.

--
Met vriendelijke groet, Ernst

Dinkla Grafische Techniek
Quad, pi\ufffdzografie, gicl\ufffde
www.pigment-print.com

On 12-04-27 1:45 AM, "Ernst Dinkla" <e.dinkla@...> wrote:

> On 04/27/2012 03:42 AM, Paul wrote:
> 
>> I was surprised that the PK to LK step was 1:1 as opposed to closer to
>> 30% PK. I did not make an LLK dilution, which, again, is typically
>> 30-33% LK, remainder clear base.
> 
> If you compared it to diluting HP PK, I always had the impression that
> the HP PK and the other Vivera greys are quite dense compared to other
> ink set grey inks. One of the reasons could be that the substitution of
> CMY grey mixes with a heavier grey etc reduces ink lay down more. There
> has to be a balance what is visually acceptable and best for the paper
> coating but the Z3100 in total has hardly any composite greys in color
> prints left and its droplets vary between 4 and 6 picoliter. Drying time
> is fast, color stabilises fast and that is also desired for the internal
> calibration + profiling if done in one run.

As another point of reference Canon's GY, their LK equivalent from Lucia EX
(6300/8300), measures 44% of their PK ink (BK). This is based on an ink load
of 75% on Canson Platine, which is Dmax for that paper. Again, the density
is greater than one might expect.

Terry.