2015-03-05 by jon@...
In terms of the differences between our blacks, they may be of more interest to those not using Piezography K6 or K7 curves.
In traditional QTR use made with QTR Curves Tool, or with black ink only printing - much more black ink is used than with a Piezography-made K6 or K7 curve. First, the linearization process I use is much different than the linearization process in QTR. What I am trying to do is get maximum separation of gray values including right up to dMax. Necessarily, I use very little black ink whereas dMax is made from 3-4 shades of black. Study one of my curves and you can visually see how this separation of tone occurs and you can see how little of shade 1 is actually responsible for dMax. Only just enough is...
So, 100% patches of single black never occur. Not even mostly a single black. Of the combined amount of ink in a typical K7 glossy curve at dMax (about 130%) - 30% is black shade 1, 43% shade 2, 33% shade 3, 18% shade 4 and 5% shade 5.
In a typical QTR curve - there would be much more black. Piezography uses two shades of darker ink than the typical LK. So, more shadow separation in values near L0 - such as L1, L2, L3, etc printing with detail. I can get the same dMax as other process, but am able to print with more shadow detail this way. Also, I do the same at the high end of things with two additional lighter shades than LLK.
So, dMax can actually exceed that of a naked or slightly supported pure black this way, and produce a greater separation of darkest grays.
Drying time is critical - as the amount of ink Piezography prints is typically 30-40% more across the board and therefore it needs dry time - and it picks up about 1/3 to 1/2 stop more dMax. A hair dryer is very efficient in just seconds whereas overnight drying is not quite enough to bring out the pick up in dMax.
The biggest comparison in K6 vs Eb6 is the side by side photograph judgement. It's not just numbers - but the ink itself. Eb6 does not use an encapsulated pigment particle (it matters), does not print with as much ink (it matters), and does not have as much separation of detail (it matters), and does not print with as much acuity (it matters). Finally, the grind and narrow distribution of particle size in Piezography ink creates a more uniformity in the reflected light back to the viewer (for some the most important). Encapsulation is a very expensive process, but it allows one more benefits than just isolating the static charge of the particle. More filtering is required and I think that benefit of having nearly all the same particle sizes is one of our best benefits in terms of how light is absorbed and reflected. That has to be seen to be appreciated.
A Piezography print produced from my curves really needs to be seen to be understood in how its different from ABW or Eb6 or any other monochromatic process for that matter. Numbers do not reveal quality. Piezography is more comparable to a platinum/palladium print (but with much more shadow detail). That glow of the pt/pd is present in a Piezography print because of the proprietary pigment treatment. And in that regard, dMax is not the absolute target. Much more its about the entire range of tone that is possible and desirable. Yet dMax is quite good.
Having said all that - there may be some benefit to using Piezography single blacks that have gone unused. We do not have a Paul Roarke to take our inks and make alternative workflows. We have never been approached and typically my users want my solution.
Piezography shades 1, 4 & 5 follow Epson black, LK and LLK.
K6 adds two darker and one lighter
K7 adds two darker and two lighter
Hope this makes more sense out of black.
Regards,
Jon Cone
Piezography
InkjetMall