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Samples of the Piezography Process Now in Test

By June 26, 2009November 4th, 2015Research

From Wikipedia: A connoisseur (Fr. connaisseur, from Middle-French connoistre, then connaître meaning “to be acquainted with” or “to know somebody/something.”) is a person who has a great deal of knowledge about the fine arts, or an expert judge in matters of taste.

An eight channel printer such as the Epson 9800 can be outfitted with two hues of Piezotone inks. A dedicated RIP (e.g., StudioPrint) can then address just one set of hues or blend them as shown in the figure above. The print colors shown in this figure were derived from the specific colorimetric measurements made directly on test target samples submitted to AaI&A. Any color “ripple” in hue between adjacent color patches that you observe on your monitor is due to the limitations of 24 bit RGB digital color reproduction on today’s electronic display technologies. It is not present in the actual print samples.

Black&white inkjet prints using composite color inket printers have come a long way in image quality in the past few years. Epson’s Advanced Black&White (ABW) mode is a good example of a special printer driver mode that configures the color ink channel blending to produce monochrome prints of very high quality. Sample # AaI_20090415_SN008 in the AaI&A light fade testing database is an example using the Epson ABW driver mode to simulate a traditional sepia tone B&W print. For many photographers, printmakers, and their clients, the resultant black&white prints produced by a modern composite color inkjet printer are more than adequate. The versatility of being able to produce both full color prints and monochrome prints with user-adjustable hue control on just one printer offers tremendous convenience. The printmaker can simulate many traditional print processes right in the printer driver ((e.g, “sepia”, “selenium” or cold tones ,etc). That said, for the absolute highest standard of image quality and aesthetics, serious printmakers may choose to dedicate an inkjet printer to a monochrome inkjet process like Piezography.

The Piezography® process was pioneered by Jon Cone of Cone Editions Press, Ltd, and the best way to understand it is to visit Jon’s website.

The concept behind Piezography and other ink formulations intended for monochrome inkjet printing is straight-forward. Replace the color inks with various shades of gray, and superior black&white prints can be made. The prints can have essentially dot-free image structure, higher image resolution, more subtle tonal gradations and superior hue uniformity (i.e, freedom from subtle hue variations that produce unwanted “color ripple” between adjacent tones). Improved print longevity is also possible, because it is generally easier to manufacture low chroma colorants that are highly stable compared to high chroma colorants. For example, highly stable pure carbon pigments can be used.

I have excerpted a few paragraphs from Jon’s website about Piezography that are relevant to the samples now in test :

“Piezography is a brand of monochromatic inks and software that produce what is unarguably the absolute highest-standard in black and white printing. It was first introduced as a Trademarked brand in 2000 and has gone through successive improvements and changes over the years…”

“Piezography inks are available in two main categories: PiezoTone (2nd Generation) and K7/K6 (3rd generation). A new generation of ink called MPS is the first universal purpose black ink on the market from any manufacturer”…”

“PiezoTone inks are made of 100% pigment and have extremely long lightfastness properties. Museum Black like PiezoTone is also made of 100% pigment. However, we offer Portfolio Black for those who wish to exhibit their prints temporarily and seek the absolute darkest dMax possible. Portfolio Black is only 92% pigment. The remaining 8% are metal hydroxides and are not very light fast. Although it is an interesting way to make black ink blacker, it is designed only for temporary use. Portfolio Black has also been found to be incompatible with the coating on Hahnemuhle Photo Rag. If it sounds like we do not recommend Portfolio Black, we don’t! We think “wanting as black a black as possible and not minding a little fade” is a wonderful thought but it never seems to match the reality of what the little fade looks like… So having Portfolio Black ink get lighter when dark gray is not, looks terrible!”

Both Portfolio Black and Museum Black ink formulations are now represented in the AaI&A database. In fact, one AaI&A member uses an eight channel Epson 9800 printer outfitted with two different hues of Piezotone ink (i.e, “Selenium” and “Carbon Sepia”) plus the Portfolio and Museum Black inks. Three channels are dedicated to the Sepia hue, three to the Selenium hue, one channel to Portfolio Black, and one channel to Museum black ink. Thus, this system can switch (or blend) between the two piezotone hues and the two black ink types depending on the requirements of the print, i.e., desired tint plus maximum density in the deepest shadows or superior longevity. As shown in the figure above, this printer/ink channel configuration and an appropriate RIP (e.g., Studio Print) can make warm tone Sepia prints, cooler tone Selenium prints, or “split tone” prints where seven channels are active in order to blend the Sepia and Selenium inks together along with black ink in the deepest shadows. Channel blending can also be used to create a true “split tone” effect where, for example, highlights may be warmer and shadows colder.

Jon’s comments about Portfolio Black versus Museum Black and the very last sentence quoted above with regard to the Portfolio black ink fading faster in comparison to the dark gray values are highly relevant to the validity of any light fade testing protocol. Such a fading outcome would challenge the test methodology to detect and measure selective fading occurring only in the darkest tones where perhaps in extreme cases a tonal reversal could occur in the darkest areas of the image. Current industry-sponsored test methods don’t even track the maximum black densities in the print, and therefore can not possibly measure the change that Jon has advised his customers may happen with the Portfolio Black. The I* metric and the monochrome test target AaI&A uses in its light fade testing protocol has no such limitations. It can detect and quantify this type of selective change if and when it begins to occur. In fact, let me cut to the chase. Even though the tests on the new piezography samples have only reached the 10 megalux hour exposure mark and will likely continue well beyond 100 megalux hours in test, the I* metric is already detecting this fading response in the Portfolio black. The test is even sensitive enough to detect subtle but real color shift differences between the sepia, selenium, and split tone versions of the print samples as the more neutral Portfolio Black begins to fade out of the blend in the darkest shadow tones.

As for the Piezotone samples made with Museum Black? They can already be seen to have significantly higher stability, and in fact there is no statistically measurable fade at this point in the testing. So, why use the Portfolio Black at all? Well, its reason for existence is to produce a richer initial black and give the photographer’s print portfolio that subtle edge in overall image quality. The maximum black values (i.e, minimum L* values) that were measured on various print samples recently submitted to AaI&A are summarized as follows:

Epson ABW mode printed on Hahnemuhle Photo Rag: L* = 17.2
Piezotone with Museum Black printed on Hahnemuhle Photo Rag: L* = 15.5
Piezotone with Portolio Black printed on Hahnemuhle Photo Rag: L* = 13.9 (average of 3 samples)

To the connoisseur of the fine art print, these subtle differences in print Dmax are recognized, and the richest blacks, albeit only subtly darker, are highly coveted. Portfolio Black does indeed live up to its reason for existence, but Museum Black strikes a respectable balance between improved Dmax compared to Epson ABW Dmax, Portfolio Black, and improved light fade resistance.

Mark McCormick-Goodhart
Director, Aardenburg Imaging & Archives