Digital BW, The Print

On 12/05/2012 07:12 PM, Paul wrote:

> At the end of the PDF I have an Appendix that looks at the HP neutral
> 50% patch performance of some of the tests at
> http://www.aardenburg-imaging.com/ .  It might be of interest to
> those who want a neutral ink that seems to have handled the
> differential fading issue the best.  The 50% neutral test patches --
> RGB and GS -- presumably have some of the color HP inks in them also.
> So, this is obviously not a perfect view of how the separate neutral
> inks will perform.  But, given the reality of incomplete information,
> the tests of the HP neutral patches are still impressive.
>
> Paul www.PaulRoark.com

Paul,

There will be no color HP inks in the patches. Not if the profiling has 
been done on the printer itself. The papers are almost neutral, the PK 
ink tends to be slightly cool b -1.6 (Pearl is b 1.6) and the Z3100 
models use an extreme UCR so no composite greys even in color mode. At 
least that is what I observed with Photorag patches under a microscope. 
The test results represent your future (Vivera only) prints too in my 
opinion. What shifts is mainly the paper white itself, L goes up 0.4-1 
DE right away like in most papers, then becomes almost stable, b gets a 
bit warmer in time.

On the unfaded Photorag patches it is interesting to see the MK patch of 
100% as neutral/warm where the 80% patch is cool, PK taking over there 
on the neutral spine, the lighter patches will be Grey and Light Grey 
ink. From the 80% to paper white the b is crossing the neutral axis, the 
paper white shift in time to warm has the same influence, no color ink 
there and no color ink shift happening in my opinion. MK black does not 
shift either. Pearl uses the PK black + the grey inks + gloss enhancer 
and has no OBA in the paper.

ColorByte learned something of what HP engineers did with the Z3100 
media presets and made similar ones for the Epson x900 models in ImagePrint:

http://www.luminous-landscape.com/essays/the_weakest_link.shtml

It can go the other way too:
When I got my HP Z3100 more than 5 years ago I upgraded my Wasatch 
Softrip to drive that printer too. The first thing I noticed was that 
Wasatch had lousy media presets compared to the HP driver. In that case 
the third party driver did a bad job on all kinds of ink mix 
substitutions; black generation, N-color hue substitutions etc. A 
microscope on the prints told enough. The HP driver relied on an extreme 
UCR and also replaced much of the cMmY mixes with RGB inks where 
possible. I noticed much more "metamerism" with the Wasatch prints and a 
higher ink consumption. I also predicted less color stability in 
printing and less fade resistance in time. The Vivera pigments are in 
itself more fade resistant than the Epson UltraChrome HDR inks (yellow 
remains weak) but the HP engineers were clever enough to improve on that 
with the design of the media presets.

For the Z3200 the UCR approach may be less Spartanic, it will be 
interesting to see whether that is reflected in the Aardenburg tests.


-- 
Met vriendelijke groet, Ernst Dinkla

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
December 2012: 500+ inkjet media paper white spectral plots.