Digital BW, The Print

Folks may also want to take a look specifically at Sample ID# 148 in the Aardenburg test results database. This sample is a very neutral B&W print sample that was printed on a Z3100 in it's grayscale mode on HN photo rag.  Presumably, HP's grayscale mode is similar to Epson ABW in maximizing use of the photogray colorants and reducing other colorants to a minimum in order to achieve the desired tint, in this case a very close "pure neutral gray" under D50 illuminant.  

Sample #148 has reached 100 Megalux hours in test, and was due for its 120 Mlux hour update in mid October. Regrettably, the exposure cycle for this batch of samples and a couple of others has been running a few months behind schedule, but the batch finally reaches 120 megalux hours tomorrow.  I hope to have the updates posted by the end of next week.

cheers,
Mark
http://www.aardenburg-imaging.com

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Ernst Dinkla <e.dinkla@...> wrote:
>
> 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.
>