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sanking
14-Jan-2012, 13:17
Just found this article by Jon Cone.

http://theagnosticprint.org/the-state-of-the-state-of-the-arts-in-black-white/#more-963

Very interesting read, especially his comments about the all carbon ink set.

Sandy King

Ken Lee
14-Jan-2012, 13:55
"The results at Aardenburg at the 140 Megalux point confirm for me that prints I make with pure carbon inks will stand the test of time, and should be considered a replacement for silver and platinum for those who are losing access to those metals."

I have read that with methods like Pt/Pd and Carbon, longevity is constrained more by the integrity of the backing material (paper for example) than the image material itself.

Does an Aardenburg number of 140 Megalux equate to the longevity of Pt/Pd or other similar processes that we place at the 'pinnacle' of stability ?

mdm
14-Jan-2012, 14:12
Well done guys. Very useful site. Thanks.

btw I am very partial to the steer/bull portrait.

Brian C. Miller
14-Jan-2012, 15:11
The article is gone. There's the links to it, the first few paragraphs, but the article is just gone now. (They claim the printer ate it. Yah, like the dog is innocent!)

mdm
14-Jan-2012, 15:16
Prima donna printers. You can see most of it in the nov/dec issue of view camera. Or if you subscribe to The Agnostic Print RSS feed with google reader, it should be there, but no guarantee.

Jay DeFehr
14-Jan-2012, 16:16
Sandy,

Thanks for posting the link. The article is full of insights, information and interesting implications. Cone's credentials are unimpeachable, and his grace and generosity towards the young upstarts is truly admirable. Cone is admittedly uneasy about the inevitability of the movement away from the handmade artifact toward the machine made one, despite all his years of innovation to that end. It's a fascinating paradox.

I also found it interesting that Cone attributes much of Epson's success in printing to their being the most "open sourced" platform, making it easier for third party inksets to be used with their machines.

The evolution of B&W photographic inkjet printing as seen, and largely manifested by Cone, is educational, and entertaining, and reminds me how persuasive and inspirational descriptions of image qualities can be. A great read, beginning to end (though I confess I skimmed over the parts about longevity). Thanks again for the link.

Jay DeFehr
14-Jan-2012, 16:17
The article is gone. There's the links to it, the first few paragraphs, but the article is just gone now. (They claim the printer ate it. Yah, like the dog is innocent!)

Strange, I just read it. It's still on my screen.

Ken Lee
14-Jan-2012, 16:47
I suspect he was making a joke, about longevity :rolleyes:

Jay DeFehr
14-Jan-2012, 17:18
I suspect he was making a joke, about longevity :rolleyes:

I see. Wow. Thanks, Ken.

Brian C. Miller
14-Jan-2012, 17:25
I suspect he was making a joke, about longevity :rolleyes:

No, 404 - page not found. Very different than longevity. When I clicked on Sandy's link this morning, I was taken to their 404 page. Then I clicked on the home page, noted the article front and center, and then clicked on the link. Once again, 404. Then I read Cone's bio, noted the article there, and clicked on the link. 404.

This is what they show for a 404:

CACHUNK! CACHUNK!
Apologies, but the page you requested may have been eaten by our printer. Perhaps searching will help.

This afternoon the page is back.

Yes, I agree, the page has lots of good information. I'm going to forward it to some people who could use the info.

Nathan Potter
14-Jan-2012, 17:26
Article is similar to what appeared in the Nov/Dec View Camera. I found it exceedingly useful in that there was a bit of history along with a discussion about current technique as exemplified by a few current printing specialists. Fascinating for me because I was not aware of the K2 outfit in Austin TX. mentioned. I must look them up.

Great credit to Simmons and Cone for getting this in print.

Nate Potter, Austin TX.

Tyler Boley
14-Jan-2012, 19:35
don't know why the link was dead for a bit, perhaps Jon did a little editing. It should be live now-

http://theagnosticprint.org/the-state-of-the-state-of-the-arts-in-black-white/

Tyler

Ken Lee
15-Jan-2012, 03:38
To answer my question concerning longevity, I had a look at the Aardenburg "explanation of the Conservation Display ratings" described in this PDF document: http://www.aardenburg-imaging.com/cgi-bin/mrk/_4082ZGxkLzBeMTAwMDAwMDAwMTIzNDU2Nzg5LyoxMDg=

A glance at the page which shows the ratings of various papers, suggests that 140 is roughly average for the samples tested. There are some Canon and Epson results which go up to a rating of 240.

According to the document, a print with a rating of 100, placed in a "South-facing window in U.S.A. , e.g., storefront display with photos directly facing window" yields a display time of 2.3 years.

Many of the store-front art galleries I see here in Massachusetts exhibit paintings in the window, just as jewelry stores display gems and watches for sale. I've seen store-front portrait studios which do the same, but I have no idea how long those photos stay on display. I presume that a well-processed Pt/Pd or Carbon print could stay there a very long time, and fade no more than a gold ring.

Please correct me if I am mistaken :o

paulr
15-Jan-2012, 08:14
I presume that a well-processed Pt/Pd or Carbon print could stay there a very long time, and fade no more than a gold ring.

Please correct me if I am mistaken :o

I did an informal lightfastness test of some piezography wedges in my window ... Northwest facing, not south, but I left them taped there for about six years. For kicks I threw in a couple of strips of toned silver prints, a drugstore c-print, and a platinum print.

Everything was cut down the middle, with one half stashed in a flatfile.

Interestingly, the platinum print showed some changes within the first six months. It looked to me like the paper base bleached a bit. This influenced the look of the image even if it had nothing to do with the image itself. After that I saw no further changes.

The color print did the worst, but it held up longer than I'd expected. Hardly any visible change until after the first year. The piezo and silver prints did not change.

I would have kept the test going, but I got really sick of seeing those things in my window.

sanking
15-Jan-2012, 09:23
Proper processing and the quality of the final support, whether paper fiber or synthetic, is very important to long term print stability.

I have personally seen pt/pd prints by well-known photographers that were stained from improper processing. And with carbon transfer many people use fixed out photo papers as the final support, and if not fixed and washed correctly these papers can cause problems.

However, palladium and platinum metals are very stable, and carbon pigment in a gelatin binder is inert, so in general the weak link of pt/pd and carbon prints is not the image, but the final support.

Although I became interested in carbon transfer because of its permanence that is not the reason I continue to work with the. The attractions for me at this point in time are 1) the act of hand crafting a print, and 2) the unique surface and textural quality of these images which is provided by the relief, which gives a three-dimensional look to carbon print.

We can perhaps make too much of longevity by obsessing over the quality. On the other hand, I have read messages by commercial printers who admit to using cheap ink sets of dubious permanence.

Sandy

Brian Ellis
15-Jan-2012, 09:35
It's always interesting but discouraging to me to read articles like this. They leave me with a feeling of complete inadequacy and the belief that there's a whole vast body of knowledge and technique out there that I should know a lot more about than I do. I've used QTR since it first became available but since abandoning MIS inks years ago I've just used the Epson inks in my 3800 with QTR to make b&w prints. I've never even tried to make my own curves or mix inks or do any of the other kinds of things that are discussed in this article. Worse yet, I have no idea how one would go about learning to do them.

sanking
15-Jan-2012, 10:48
Brian,

No reason to be discouraged. Using QTR with the Epson inks to make monochrome prints is a perfectly viable way to work in my opinion. The prints may not have as much longevity as prints made with an all carbon ink set but I know from experience that they can be displayed for a long time with no color shift. I have had some split toned prints on my wall for many years made with QTR/Epson 2200/Epson UC pigment inks and they look as good to my eye as the day they were made.

You could set yourself up with a Piezography K7 set for the Epson 3800 and be making perfect prints in a few days with QTR. Problem is, you now have a dedicated monochrome printer and can no longer make color prints. Also, using QTR with color inks, either Epson or Cone, gives you some split toning possibilities that you lose with Piezography. Though Cone seems to have an interesting new set for the 3800 that may allow for split toning.

And just for the record, the guys mentioned in that article are professionals who make their living printing for others. They can justify spending the time and setting up multiple printers with specific ink sets. People like you and me who just print our own work generally lack the time, space or inclination for this.

Sandy

Oren Grad
15-Jan-2012, 11:16
Using QTR with the Epson inks to make monochrome prints is a perfectly viable way to work in my opinion. The prints may not have as much longevity as prints made with an all carbon ink set but I know from experience that they can be displayed for a long time with no color shift.

You can use QTR with the Epson K3 set to make carbon-only prints - per recent release notes, the "warm" profile uses "K, LK, and LLK inks i.e. carbon only".

The catch is that, like other carbon-only inksets, it produces a distinctive, warm tonal scale. I mostly don't care for it myself - I prefer something more neutral for most of my pictures. Unfortunately, so far as I know there is at present no inkset that offers both maximum stability and tonal neutrality.

Tyler Boley
15-Jan-2012, 15:39
Apparently there are ways to manipulate the hue of carbon in the ink manufacture process, though it is generally warm. The Epson k inks are warm in a yellowish way, not attractive to many. Of course this is not a prblem for Epson as hue is adjusted as desired in the ABW driver with color inks, or in color printing with color management. Cone K7 carbon set is more of an appealing warm hue perhaps a touch rosy compared to yellow.
When the extremes Caponigro went through to find the sweet spots for each and every image in the darkroom were described to me I too was intimidated. The point was, though, no matter what I did myself there were further levels to explore resulting I amazing art should one chose to commit.
What I love about Jon's piece is that it clearly shows there are much higher levels of craft in ink in a wide variety of ways than most are aware, even in education. In fact our most recent gathering was at the national SPE conference. No one but us lowly printers were present, up all night showing work and ranting art. Not a single educator, artist, curator, no one. The bars were full though.
Anyway, I think it's great to know you can take things much farther should you chose and it is still possible to make extraordinary objects even in the world of ink.
Tyler

sanking
15-Jan-2012, 16:26
Apparently there are ways to manipulate the hue of carbon in the ink manufacture process, though it is generally warm. The Epson k inks are warm in a yellowish way, not attractive to many. Of course this is not a prblem for Epson as hue is adjusted as desired in the ABW driver with color inks, or in color printing with color management. Cone K7 carbon set is more of an appealing warm hue perhaps a touch rosy compared to yellow.

Tyler

Tyler,

All of the pure carbon pigments I have used to make carbon tissue have been on the warm side. I like warm prints, and often add a bit of burnt umber or sienna to make the color of my prints even warmer. But I might just as well go in the other direction and add violet, magenta or cyan to give a cooler tone. There is no one single hue or color that works for every image, as there is no single paper. Thankfully no one has to print for me because I would be a difficult customer to satisfy!!

I really enjoyed reading about your work. Sounds very cutting edge to me.

And yes, no question but that Jon Cone is much more than a seller of ink. Hopefully those kind of comments will not put him off contributing to this forum.

Sandy

Lenny Eiger
15-Jan-2012, 17:48
You can use QTR with the Epson K3 set to make carbon-only prints - per recent release notes, the "warm" profile uses "K, LK, and LLK inks i.e. carbon only".

The catch is that, like other carbon-only inksets, it produces a distinctive, warm tonal scale. I mostly don't care for it myself - I prefer something more neutral for most of my pictures. Unfortunately, so far as I know there is at present no inkset that offers both maximum stability and tonal neutrality.

Oren,
I use both a carbon sepia and a selenium tone ink set from Cone. I mix them for a neutral. It's a warm neutral, to be sure, but the selenium on its own is very cool, not warm at all...

Lenny

Oren Grad
15-Jan-2012, 18:24
I use both a carbon sepia and a selenium tone ink set from Cone. I mix them for a neutral. It's a warm neutral, to be sure, but the selenium on its own is very cool, not warm at all...

Understood. I can get a quite neutral tone out of the Epson K3 inkset with QTR as well using a different profile, with the advantages of QTR's superior detail rendering and tonal smoothness compared with Epson ABW. But neither these nor the corresponding Cone inksets match the stability of a carbon-only approach, and the carbon-only "look" isn't right for everyone or everything. Those were my only points here.

No slight intended to Jon Cone here - his insights and his products greatly expand the scope of creative possibility for a craftsman who is willing to put in the effort to master them.

Tyler Boley
16-Jan-2012, 11:53
...
No slight intended to Jon Cone here - his insights and his products greatly expand the scope of creative possibility for a craftsman who is willing to put in the effort to master them.

quick interjection to dispel any prevailing misperceptions.. the article did discuss many complex approaches to working with ink. However the standard K7 setups readily available are plug and play and sinple to master. I had a class of beginners printing to a little 1400 with the SE inkset in 5 minutes.

Tyler Boley
16-Jan-2012, 12:04
Tyler,

All of the pure carbon pigments I have used to make carbon tissue have been on the warm side. I like warm prints, and often add a bit of burnt umber or sienna to make the color of my prints even warmer...
...
I really enjoyed reading about your work. Sounds very cutting edge to me.
...
Sandy

I too like warm prints, and one reason my setup is variable is that I, like you, tend to hue each image as I see fit. Of course making various tissues to try and find each images sweet spot is way more involved, no question.
Being cutting edge for me is not an end in itself. I've been working with this setup for 9 years now, and it feels very second nature, as I'm sure your process does to you. It did migrate from a 9600 to a 9880, but it's the same otherwise. I just found myself there trying to get the prints I wanted.
Technique and tools are of great interest when it comes to craft perfection, finding and pushing the possibilities... but if you've ever watched Oscar Peterson (RIP) play, technical ability beyond comprehension, that stuff evaporates, all his tools are at hand instinctually, and he's just talking to you even if you don't know the language.
Countless other examples... sure you know what I mean.
Tyler

Nathan Potter
16-Jan-2012, 12:59
Tyler, so well said. Craft perfection at a higher level goes beyond what can be communicated. It almost seems to become embedded in ones DNA after some years of trial and error, and some successes. The art form doesn't much matter and certainly the photographic technique doesn't matter. But the keen observer will see something in the end result which will make their hair stand on end and bring tears to their eyes, especially when viewed within the framework of their own efforts. Such is the moving target of inkjet printing. Exciting stuff on its own I find.

Nate Potter, Austin TX.

sanking
16-Jan-2012, 14:29
quick interjection to dispel any prevailing misperceptions.. the article did discuss many complex approaches to working with ink. However the standard K7 setups readily available are plug and play and sinple to master. I had a class of beginners printing to a little 1400 with the SE inkset in 5 minutes.

Yes, it is amazing how simple it can be to make good monochrome prints with QTR and a Piezography in set. It is really plug and play, no need to mix inks, etc.

But if for any reason you want to keep a color ink set in your printer, it is also very easy to make nice monochrome prints with QTR and either the Epson K3 or Cone color ink sets.

Basically, QTR is a great bargain if you want to make monochrome prints. You can download and try it for free, and if you want to be a legal owner the cost is only about $50. It is a very powerful driver that I much prefer to the Epson driver for either making inkjet prints or digital negatives.

Sandy

Tyler Boley
16-Jan-2012, 17:42
yes I should have added that at the same class, people were printing B&W with OEM ink out of a 3800 in 5 minutes as well. I was just trying to dispel the idea that the plug and play alternative ink options require some masterful extra effort, those days are long past.
Roy should get some kind of award for QTR, such a powerful tool.
Tyler

D. Bryant
16-Jan-2012, 20:45
but if you've ever watched Oscar Peterson (RIP) play, technical ability beyond comprehension, that stuff evaporates, all his tools are at hand instinctually, and he's just talking to you even if you don't know the language.
Tyler

+1 for Peterson. FWIW, he was also an amateur photographer.

MHMG
17-Jan-2012, 17:25
A glance at the page which shows the ratings of various papers, suggests that 140 is roughly average for the samples tested. There are some Canon and Epson results which go up to a rating of 240.

According to the document, a print with a rating of 100, placed in a "South-facing window in U.S.A. , e.g., storefront display with photos directly facing window" yields a display time of 2.3 years.

Many of the store-front art galleries I see here in Massachusetts exhibit paintings in the window, just as jewelry stores display gems and watches for sale. I've seen store-front portrait studios which do the same, but I have no idea how long those photos stay on display. I presume that a well-processed Pt/Pd or Carbon print could stay there a very long time, and fade no more than a gold ring.

Please correct me if I am mistaken :o

Ken, the average of 140 Megalux hours with max of 240 are values in the "Status" column in the AaI&A database. The status column tells how much exposure has accumulated in ongoing tests for each sample. The accumulated dose is not a performance rating. It's simply a reporting of how far the test has gone in terms of accumulated exposure to date. For the AaI&A Conservation display ratings which do allow a quick product performance comparision without having to download the reports, you will want to check the values in the Conservation Display rating column. The Conservation Display rating (CDR) indicates the range of light exposure that each sample tolerates while remaining in very good to excellent condition with little or no noticeable fade even though some fade can be detected with instrumentation. Because the CDR is tracking very early stage fading and because higher doses are then necessary to observe more easily noticeable fade and because fading curves are often non linear, AaI&A always takes the exposure doses on the sample well beyond the amounts needed to produce the CDR. Additionally, color and tonal accuracy scores are listed in all reports at uniform exposure intervals (expressed in megalux hour units), This information enables the end-user to compare and contrast product performance at many other accumulated exposure levels, even doses that push some samples well into the severely faded state. You will find examples where one product might actually do better than another in the early stages of fade, but then worse as more advanced stages of fading occur at even higher exposure doses.

I hope this explanation helps. The CDR column in the AaI&A lightfade database is a good "executive summary" for the early stage fade resistance which is what I believe is more important to serious printmakers, collectors, and curators. Again, it represents the light exposure grace period where excellent image color and tone has been retained. To further translate the CDR to "years on display" Ken has got the right idea in his example. Look in the table in each report and choose a descriptive light level that suits your anticipated display condition. Or take some measurements with an inexpensive light meter for an even more accurate estimate of your print's average light level on display. As Ken correctly noticed in his example, when the light level gets high, high exposure doses accumulate rapidly. At about 228 average lux for 12 hours per days "megalux hours" = years (.e.g, 100 Mluxhrs will accrue in 100 years on display), but in bright "front window" display areas, average lux levels are much much higher, and the time to reach a given exposure dose goes down proportionately (Exposure = intensity x time, ie. the classic Reciprocity Law of photography).

The huge variability in "average light levels" on display is why AaI&A expresses its Conservation Display ratings in megalux hours and doesn't extrapolate the test results to rated "display years" as other labs do. We leave that up to the end user to estimate. It not hard to do using the reciprocity law or a table of values as seen in any AaI&A report, and the end user is in a much better position to decide what that average light level is likely to be.

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

Ken Lee
21-Jan-2012, 08:52
Thank you for clarifying.

I had a fresh look at the Light Fade Test Results, with attention to the CDR numbers (Conservation Display Ratings).

I see that in rough terms, the range goes from roughly 1 to 150, with the highest rating given to the HP Designjet Z3100 24" + Crane Museo Rag paper: 152 Megalux. Left in the "south-facing window", such prints would exhibit little fading until after (152/100 * 2.3) = 3.5 years.

What does it mean that the rating for Epson Stylus Pro 9800 with Cone Piezotone™ (Carbon Sepia with Portfolio Black) inks on Hahnemuhle Photo Rag paper, has a CDR of "9-140" ? What does the 9 designate ? Most of the ranges we see in the test results are closer: 65-87, 80-88, etc.

Members can view the detailed reports, and compare original versus exposed color patches (Man, are you ever thorough!). Looking at the test of the above-mentioned HP printer after 180 Megalux hours, it's remarkable how little difference there is to the naked eye. On the other hand, doing the same for the Piezotone test, differences are apparent at lower numbers. Is that because it is easier for the eye to discern fading of patches in monochrome than in a wide range of colors ?

We are lucky to have you on this forum :)

MHMG
21-Jan-2012, 10:42
I see that in rough terms, the range goes from roughly 1 to 150, with the highest rating given to the HP Designjet Z3100 24" + Crane Museo Rag paper: 152 Megalux. Left in the "south-facing window", such prints would exhibit little fading until after (152/100 * 2.3) = 3.5 years.


Yes, direct sun is a harsh mistress for any artwork. Even pure cotton papers and photographic grade gelatin binders will degrade within a decade or so under the "front facing window" scenario, so that even if the image is formed with a noble metal like Pt or Pd the organic support layers will ultimately let the system down before the image forming components fade.



What does it mean that the rating for Epson Stylus Pro 9800 with Cone Piezotone™ (Carbon Sepia with Portfolio Black) inks on Hahnemuhle Photo Rag paper, has a CDR of "9-140" ? What does the 9 designate ? Most of the ranges we see in the test results are closer: 65-87, 80-88, etc.


The sample you are referring was made with Portfolio black ink. Jon Cone has offered two matte black ink formulations over the years, one he calls "museum black" and one he calls "Portfolio black". Portfolio black gives somewhat richer dmax but Jon freely admits it's not as stable as museum black. The current CDR of "9-140+" means the lower CDR limit triggered very early in test at just 9 megalux hours due to changes occurring in the worst 10% of patches, ie. primarily in target patches E5, F4, and F5 (take a look at the table data for those patches in the reports). These are essentially the only patches where the Portfolio black ink was being feathered into the mix. F5 is the dmax patch, and dmax areas often have an excess of ink so there's some "sacrificial" protection to the dmax patch density due to this excess ink. Yet this patch has still changed somewhat, but in patches E5 and F4 the Portfolio black was being "feathered" into the mix by the printer RIP at a much lower level and it faded rather quickly, leaving behind the warmer carbon particles which give these patches the majority of their color and tone. Thus, those patches shifted a little in hue towards a more sepia appearance in less than 10 megalux hours exposure. That's what triggered the lower CDR rating of 9 megalux hours. As the tests proceeded some additional fading in those patches has continued whereas all other patches are highly stable due to the full carbon content. Because the highlight, midtone, and shadow image tones are comprized solely of the pure carbon pigment (i.e, no portfolio black mixed in) they are on average quite stable, and this is the reason why the upper CDR limit still hasn't triggered. Note: When you see a "+" sign in the CDR column it means the upper limit still hasn't been triggered (e.g., in this sample the test has now gone 140 megalux hours and the upper CDR limit will eventually be at least that good but probably better). This sample and two others using the Portfolio black ink are rather unique examples of inkjet craft. It's really what the AaI&A Printmakers' Testing fund is all about - giving artists a chance to collaborate with AaI&A and submit examples of craft that would likely never get tested otherwise.. in other words, these are real world results for what dedicated printmakers are doing with inkjet technologies these days.




Members can view the detailed reports, and compare original versus exposed color patches (Man, are you ever thorough!). Looking at the test of the above-mentioned HP printer after 180 Megalux hours, it's remarkable how little difference there is to the naked eye. On the other hand, doing the same for the Piezotone test, differences are apparent at lower numbers. Is that because it is easier for the eye to discern fading of patches in monochrome than in a wide range of colors ?


You got that exactly right, and it's a significant reason why I invented the I* metric. I concluded that traditional densitometry and color difference equations were inadequate to evaluate visual changes occurring in photographs, either due to aging over time, or even when, say, one compares a copy image to an original image for tone reproduction quality. Traditional color difference models (delta E, delta E 2000,etc) evaluate two side-by side colors merely for colors' sake. They are thus an excellent metric for process control, but in paintings, drawings, and photographs we see a complex assortment of colors and tones that form contextual meaning. The human brain interprets this context (e.g., pattern recognition, scene color balance, etc) and in doing so relies on the low chroma colors (i.e. neutrals and near neutrals) as a kind of baseline for evaluating the color appearance of the scene lighting, ie. how cool or warm the light of the scene is when judging the color and tones in that scene. We also detect the visual contrast of neighboring image areas which is what pattern recognition is all about, so I* tone calculates the L* gamma for near-neighbor tones in order to determine changes in both lightness and contrast whereas I* color tracks changes to hue and chroma accuracy. Color difference models lump lightness, hue, and chroma together, so the important role of image contrast in retention of overall image quality does not get evaluated properly.

If you'd like to see a good visual example of color in context versus color purely for colors' sake, take a look at the article "An Introduction to the I* metric" on the documents page of the AaI&A website. The direct link to the article is:

http://www.aardenburg-imaging.com/cgi-bin/mrk/_4605ZGxkLzBeMTAwMDAwMDAwMTIzNDU2Nzg5LyoxMQ==


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

Ken Lee
21-Jan-2012, 11:57
Wow


Traditional color difference models...are thus an excellent metric for process control, but in paintings, drawings, and photographs we see a complex assortment of colors and tones that form contextual meaning. The human brain... relies on the low chroma colors (i.e. neutrals and near neutrals) as a kind of baseline for evaluating the color appearance of the scene lighting,


It will take a while to absorb the entire article, but the photos you show on page 13 illustrate your point quite dramatically... and remind me why I work in monochrome ;)

MHMG
21-Jan-2012, 17:51
Wow



It will take a while to absorb the entire article, but the photos you show on page 13 illustrate your point quite dramatically... and remind me why I work in monochrome ;)

Ken,

Yes, I didn't take the time to go back through the article and cite the appropriate page, but you have indeed found it. You clearly have a good handle on what these concepts are all about. I hope it sheds some light (pardon the pun) on why single value print longevity numbers are for the most part grossly oversimplified assessments of overall system light fade performance. Almost any print can easily "last" over 100 years if one chooses benign display environments and allows for moderate to high changes in visual appearance of the print over time. That reality doesn't negate the fact that some systems are far more stable than others and will tolerate excursions into not-so-benign environmental conditions for longer periods of time while still retaining good to excellent visual and physical properties.

best,
mark