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Author Topic: Dye versus Pigment  (Read 10184 times)

ChuckT

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Dye versus Pigment
« on: April 18, 2013, 08:22:49 am »

In the recent webinar/ad (No, this is NOT a plug) for B&W printing on Ilford paper I think I heard that Dye and Pigment inks had been improved to the point that they had similar life spans.  Is there any substance to that?

cvt
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Ernst Dinkla

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Re: Dye versus Pigment
« Reply #1 on: April 18, 2013, 08:53:37 am »

No, not as a general rule.

In another thread here on Ilford Gold Mono Silk that assumption was made by an Ilford representative too. I have not seen any independent testing so far that suggests it could be true for Ilford papers. Best result you can see is some custom B&W dye inkset testing at Aardenburg Imaging. Paul Roark project with Claria/Noritsu black dye. With some extra protection it would pass some third party pigment inks and equal at some point Ultrachrome inks.
Google: Paul Roark Aardenburg Claria Noritsu

Dye inks like Epson Claria and HP Vivera DYE did improve a lot compared to other dye inks but are still behind pigment inks that did improve too: HP Vivera Pigment and Canon Lucia for example. Dye inks are also still more relying on compatible media for their longevity and there are other issues like humidity.

There seems to be some confusion at Ilford, actually on more aspects of inkjet media.

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http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
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Bart_van_der_Wolf

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Re: Dye versus Pigment
« Reply #2 on: April 18, 2013, 09:34:57 am »

Dye inks like Epson Claria and HP Vivera DYE did improve a lot compared to other dye inks but are still behind pigment inks that did improve too: HP Vivera Pigment and Canon Lucia for example. Dye inks are also still more relying on compatible media for their longevity and there are other issues like humidity.

Like Ernst, that's also what my reading of the situation is. And it's not unexpected, when you consider that water solvable dye will be more accessible for the transportation of harmful agents, because moisture/humidity is an aspect of the atmosphere. Non-water solvable pigment on the other hand will be harder to penetrate/react with. Pigment does pose a few other challenges like clogging / bronzing / gloss uniformity / larger droplet size / etc.

Cheers,
Bart
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John Nollendorfs

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Re: Dye versus Pigment
« Reply #3 on: April 18, 2013, 12:01:47 pm »

Aside from what Ernst has pointed out, I would also like to point out that most pigment printers are printing on microporous inkjet receptor media. For best life, dyes should be printed on swellable polymer receptor media.

I make the distinction for a couple of reasons. First, even pigmented inks are susceptible to fade from airborne contaminates, especially ozone, when printed on microporous media that is not sealed. For this reason, it is strongly advised to frame prints behind glass, or laminates.

Second, dye inks can last nearly as long as pigmented inks when printed on recommended swellable polymer media, provided humidity conditions are relatively low (less than 40%, lower is even better). Dyes' short fall is incompatibility between certain dye colors, leading to premature failure when allowed to mix. In chromogenic processes, we had the different dye colors separated into distinct layers. Inkjet prints don't have that feature, and in heavy colors, the dyes can intermingle. With the swellable polymer technology, the droplets tend to isolate and not mix as much. Under higher humidity conditions, even the swellable polymer will allow the dyes to migrate and intermingle. Hence the problem with premature failure at higher humidity storage conditions.

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Ernst Dinkla

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Re: Dye versus Pigment
« Reply #4 on: April 18, 2013, 03:29:34 pm »

John,

Swellable papers are a dying breed though, Ilford ceased to make them, Felix Schoeller has only two left and Kodak sells the same two papers and some other media with swellable coatings. Too slow for the inkjets of today. For the dry minilabs etc that need fast drying papers a new category of microceramic papers with mordants is produced that should be compatible with the dyes used by Epson/Noritsu/Fuji. Epson introduced a new dry minilab some time ago with CcMmYK Ultrachrome D = dyes, most likely another Claria offspring. Compared with chromogene minilab prints they have a better longevity as I understand it. Which could be sufficient for that market.

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

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tim wolcott

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Re: Dye versus Pigment
« Reply #5 on: April 18, 2013, 11:01:59 pm »

Dyes will not last as long as pigments.  Pigments are particles, and dyes have and always will fade at a much faster rate.  Not to mention the dyes will never ever look as good as a pigment particles since the light when it hits a particle will ALWAYS look far more realistic.  The other question is how stable it is to water and other liquids.  Remember when light hits a dye based print the light passes thru the dye hits the sub straight then goes back thru the dyes to the eye.  Pigments will always rule.  T
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Ernst Dinkla

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Re: Dye versus Pigment
« Reply #6 on: April 19, 2013, 05:54:01 am »

Dyes will not last as long as pigments.  Pigments are particles, and dyes have and always will fade at a much faster rate.  Not to mention the dyes will never ever look as good as a pigment particles since the light when it hits a particle will ALWAYS look far more realistic.  The other question is how stable it is to water and other liquids.  Remember when light hits a dye based print the light passes thru the dye hits the sub straight then goes back thru the dyes to the eye.  Pigments will always rule.  T

Dyes give better subtractive color mixing due to their transparency which will create a wider gamut if the same number of hues are used that a comparable pigment ink set uses. A simple CMYK or CcMmYK ink set will show that already. Colorant power of a dye ink can be higher for several reasons among them the transparency and that two times filtering you sketched above. Black dye gives a higher Dmax on matte and gloss papers. Dyes usually create better gloss prints with less gloss differential and bronzing. If the longevity problems of dyes is solved I would not hesitate to go that route, the more as they tend to give less issues in the printer.

Printing the desert with pigments for a more realistic look? I do not get that association. If it exists then I would select dyes to print the sea. I have printed with dyes on matte papers and the prints looked very nice and were less fragile. Pigments in inkjet inks are more related to dye colorants than most people think and the new dyes discussed here are closer in structure to the inkjet pigments than before.

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Met vriendelijke groet, Ernst

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

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Re: Dye versus Pigment
« Reply #7 on: April 19, 2013, 08:21:24 am »

Relevant to this discussion is a direct comparison of two dye sets and two pigment sets  printed on the same paper type and now in test at:

http://aardenburg-imaging.com/cgi-bin/mrk/_4534c2hvd19kb2NfbGlzdC80

Compare ID#s 273, 275, 276, and 277. The testing is only at the 10 megalux hour mark which is still very early in testing, but some interesting results have already occurred.  The Paper is a low OBA content RC paper made by Red River. There's one third party dye, one third party pigment, Epson OEM Claria dye, and Epson K3VM pigment being run side-by side in test on this paper. The third party dye already exhibits serious fading, but the Epson Claria dye set is outperforming the third party pigment so far. This result is surprising not only for the dye versus pigment discussion but also because Claria's non linear fade behavior means it fades fastest in the early stages of "just noticeable" fading before slowing down to settle in for a very good performance rating when judging is based on more "easily noticeable" fade. Hence, the fact that the Claria dye is outperforming both a third party dye and a third party pigment set at this early stage of light induced fading strongly reinforces the fact that not all dyes or pigments are created equal and very good dyes under certain circumstances will outperform lesser pigments! That said, the best pigments on the market are still best in class for light fastness and hence the reason most fine art printing where archival quality is a concern is being done with pigmented ink sets.

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

« Last Edit: April 19, 2013, 08:26:00 am by MHMG »
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John Nollendorfs

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Re: Dye versus Pigment
« Reply #8 on: April 19, 2013, 12:24:32 pm »

Very interesting findings Mark! Again, I commend you for all the work and information you have provided on fading.

Too many neophytes tend to clump all pigments, or all dyes into singular categories. Every dye set, and pigment set will behave differently when it comes to fading, and oxidation potentials. Also, substrate is still very important. Just because the pigment set will show very good fading resistance on one paper, doesn't necessarily hold for another.

HP's pigmented ink set appears to be the "champ" when it comes to longest life. Also, they have matched their gray pigments for neutrality, giving a very long lasting, B&W print capability.

It is too bad that Ilford is "giving up" on their swellable polymer papers. Of course they are probably more expensive to coat properly, and as you mention, they take longer to dry. But they are attractive, since they do in essence seal the inks from atmospheric oxidation to a much greater degree.

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MHMG

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Re: Dye versus Pigment
« Reply #9 on: April 19, 2013, 01:01:23 pm »


It is too bad that Ilford is "giving up" on their swellable polymer papers. Of course they are probably more expensive to coat properly, and as you mention, they take longer to dry. But they are attractive, since they do in essence seal the inks from atmospheric oxidation to a much greater degree.


I'm not surprised at all. In fact, I was more surprised that swellable polymer inket media ever went to market in the first place. Traditional photographic gelatin is a swellable polymer. It is essentially carefully refined yet thermally degraded collagen extracted from ground up cattle bones. Traditional photographic gelatin remains in a gel state that holds itself together when wet. Otherwise it would dissolve during wet processing.  However, this amount of swellability (swellableness?) was not enough for inkjet printers laying down lots of ink rapidly onto the surface, so much more solubilized gelatin was incorporated in inkjet media along with other swellable polymers like PVA. End result: if a swellable inkjet print gets wet the whole image layer dissolves, and if it gets merely humid, the image layer gets really tacky. Ignoring the dissolving image problem when struck by water, even the normally high real world relative humidity conditions over two thirds of the industrialized world were enough to cause serious sticking and ferrotyping problems when these swellable inkjet media were stored stacked or touching other surfaces as in photo albums. They have to be kept at low to only moderate RH, and that's hard for many consumers to do. Even stacking the fresh (and still moist) prints up in the printer tray became problematic which is why the HP versions (the original formulation for HP premium plus photo papers) had a very strong anti-blocking layer on the verso made from ratther gritty silica particles.

Additionally, there's another RC paper problem looming behind the scene that I"m just  starting to research, and in my initial surveys for this problem, the HP Premium Plus line of swellable papers exhibited some of the worst of this little discussed phenomenon. The problem, for lack of a better description is: "light-induced post-exposure dark storage staining". Basically, prints that have been on display which exhibit the problem will show high yellowish stain formation in media white and highlight areas during dark storage a few months after being taken off of display. This level of stain does not occur on the same media in the same dark storage environment if it had not been previously exposed to light, and the stain is somewhat reversible by further exposure to light. It's a challenging research problem affecting to various degrees numerous RC papers and perhaps a few non RC media. The research challenge will be to understand the light intensity reciprocity behavior, ie. how high a light intensity and for how much exposure causes the problem in real world display/storage keeping scenarios.  Bottom line: much more research to do. And I may need some help.  It's a solvable issue because there are chemical clues located in those RC papers that have little or none of the problem compared to those that do. BTW, although the HP swellable RC papers are now off the market some of the most popular microporous RC papers in today's market also exhibit the phenomenon.

best,
Mark

« Last Edit: April 19, 2013, 01:27:27 pm by MHMG »
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