From: Robin Myers <robin@rmimaging.com> Subject: Phosphors Date: August 8, 2014 at 6:31:58 PM PDT To: Steve Jenkins <sj9000@comcast.net>
Oh, while we're on the subject, correct me if I'm wrong, but aren't the fluorescent agents, used for OB, absorbing UV, which we pretty much can't see, and the "agent" emits light at a lower frequency, to a part of the spectrum we do see -- which happens to be blue? Obviously there are phosphors out there that can fluoresce across the full spectrum(remember CRTs). So, is it the cost that prevents OBs from being full spectrum? Or some kind of energy issue ( i.e. CRTs used high energy electron beams to excite the phosphors)?
You are correct in how the optical brighteners (OB) or fluorescent whitening agents (FWA) in paper operate. CRTs used three phosphors in checkerboard patterns or striped arrays to produce colors when activated by one (e.g. Trinitron) or three (traditional) electron beams. The blue and green phosphors were broadband, the red phosphor was usually one based on rare-earth elements and produced several narrow band emissions. Most white LEDs are made with a single broadband yellow phosphor excited by a blue LED. This works well for lighting where the color rendition is not very important such as architectural lighting, street lighting, flashlights, etcetera. These LEDs are usually deficient in cyan and red emissions but seeing is more important than color quality with these LEDs. Now that LEDs are starting to be used for retail purposes where the color is very important such as clothing displays, meat markets, cosmetics, etcetera, the LED manufacturers are beginning to use two or more phosphors to improve the color rendering properties. On that same topic, fluorescent lamps use a similar method for creating visible light, just substitute UV from excited mercury vapor for the blue LED. Continuing that parallel there are fluorescent lamps with one, two or three phosphors. In the CIE list of standard fluorescent illuminants the lamps usually used for color tests are the F2 (single phosphor, cool white fluorescent), F7 (dual phosphor, D65 simulator) and F11 (triple phosphor, Philips TL84, Ultralume 40) lamps. More phosphors are ocassionally used to improve the color rendering such as in one viewing booth manufacturer's lamps where six phosphors are used to produce a high color quality light source. I encourage everyone to learn more about light by experimentation. Some experimental supplies can be found at Edmund Scientifics (http://scientificsonline.com), Educational Innovations (http://educationalinnovations.com) or other experimental supply vendors. Try diffraction gratings to see the spectrum (some vendors offer glasses with diffraction grating lenses), or a cheap spectroscope (about $10) with a scale for getting a wavelength reading, then get out and measure the world. You might be surprised by what you will find. Robin Myers rmimaging.com
Oh, while we're on the subject, correct me if I'm wrong, but aren't the fluorescent agents, used for OB, absorbing UV, which we pretty much can't see, and the "agent" emits light at a lower frequency, to a part of the spectrum we do see -- which happens to be blue? Obviously there are phosphors out there that can fluoresce across the full spectrum(remember CRTs). So, is it the cost that prevents OBs from being full spectrum? Or some kind of energy issue ( i.e. CRTs used high energy electron beams to excite the phosphors)?<
I doubt there are paper friendly and affordable OBAs (FWA, Fluorescent Whitening Agents) available that absorb UV and emit the absorbed energy evenly throughout the visual spectrum. Even if available there will not be much need for it. The light reflection of pure cellulose as used in papers is already high at the red end of the visual spectrum and can be improved with whitening agents like TiO2 and Barite. 98% reflection at that warm end is not uncommon. Without OBAs it is however hard to achieve a completely neutral paper, even the best OBA less papers have a Lab b 2 at most. To bring it to neutral, b 0, little amounts of blue emitting OBAs are needed, usually stilbene dyes, other whitening agents and pure cellulose are then still needed to keep overall white reflection high and even over the visual spectrum. To give papers the often preferred cool white reflection b -2, -5, -10 there is more OBA needed. If papers are not judged on their Lab values, spectral plots of the light reflection or whiteness but on their brightness (which is measured on the blue 457 nanometer wavelength) then cheap blue emitting OBAs often disguise the low light reflecting properties of the basic paper, a spectral plot will show a drop of the light reflection in the green-yellow-orange range, say around 570 NM. With both OBAs and bad quality cellulose fibers prone to color shifting in time, the brightness will not last and the whiteness will become even worse. Within the blue emitting OBAs there are differences in quality due to their resistance to UV, visible light and gas fading that will influence their fading or color shifting in time. The distribution of the OBA dyes within the paper structure has an influence as well, little of it and only on top of the paper coating gas fading will take its toll. Spectral plots tell a lot: http://www.pigment-print.com/spectralplots/spectrumviz_1.htm Good fade resistance testing too if it includes the paper whites: http://www.aardenburg-imaging.com/ -- Met vriendelijke groet, Ernst Dinkla Grafische Techniek Quad, piëzografie, giclée www.pigment-print.com
On Aug 8, 2014, at 6:32 PM, Robin Myers <robin@rmimaging.com> wrote:
You are correct in how the optical brighteners (OB) or fluorescent whitening agents (FWA) in paper operate.
Also, to clear up something else I think might be confusing Steve: narrowband and especially monochromatic effects are the exception, not the rule -- and even in sources we generally think of as being very "spiky." A great example is mercury, the main source of emissions in fluorescent bulbs. Start here: http://physics.nist.gov/PhysRefData/ASD/lines_form.html and put in Hg I for the spectrum, 350 and 800 for the lower and upper wavelengths, and tick the button for the line identification plot. At the very bottom of the form, click the "Retrieve Data" button. On the next page, you'll see every emissions line NIST knows about for Mercury in the visible spectrum -- and there're at least a couple hundred such lines. At the very bottom is a link to a PDF with the location of each line. There're a lot of noticeable gaps, but there're also lots of overlapping sections. However, all but of a few of those lines are vanishingly faint in relation to the few prominent lines you might be familiar with. Same thing even with Hydrogen, the least cluttered of spectra; it's very messy in the far violet / near UV range. If you want to see this in effect for yourself...get or make yourself a spectrometer for visual observation and some fluorescent objects. For light sources (such as bulbs) too bright for safe or comfortable direct observation, a diffuser of PTFE thread seal tape is perfect -- poor man's Spectralon. Either bounce the light source off a few layers of the tape, or cover the entrance slit of the spectrometer with the tape and point it at the source. You'll see the sharply-defined lines (with the sharpness of the lines depending on the design and quality of the spectroscope), but you'll also faintly see most or even all of the rest of the spectrum. (Of course, this also depends on how well you block out stray light.) So, while quantum mechanics tells us that these effects are quantized and come in neat discreet packages, quantum indeterminacy also tells us that you've got a bit of wiggle room...and the sheer complexity of systems of so many different elements and compounds (just how pure _is_ the mercury vapor in that glass tube?) makes it such that it's very, very hard to ever actually encounter truly monochromatic effects -- and, most of the time, what you get is broadband. For optical brighteners, this is a good thing. The ideal optical brightener would perfectly balance out the natural gradual drop in reflectivity at the blue end of the spectrum found in most substrates -- which means the most fluorescence at violet and a slow taper to no fluorescence somewhere around yellow, in inverse proportion to the spectrum of the paper. Or, you can go with a coating (with barium sulphate being perhaps ideal) that itself has a flat spectrum without any need for fluorescence, which is what the very best papers do. ...thinking about it, baryta-coated Tyvek might be the ultimate in neutral white papers intended for framing. Any paper manufacturers reading this who want somebody to play with such a paper, give an holler.... Cheers, b&
You are correct in how the optical brighteners (OB) or fluorescent whitening agents (FWA) in paper operate.
Also, to clear up something else I think might be confusing Steve: narrowband and especially monochromatic effects are the exception, not the rule -- and even in sources we generally think of as being very "spiky."
A great example is mercury, the main source of emissions in fluorescent bulbs. Start here:
http://physics.nist.gov/PhysRefData/ASD/lines_form.html
and put in Hg I for the spectrum, 350 and 800 for the lower and upper wavelengths, and tick the button for the line identification plot. At the very bottom of the form, click the "Retrieve Data" button. On the next page, you'll see every emissions line NIST knows about for Mercury in the visible spectrum -- and there're at least a couple hundred such lines. At the very bottom is a link to a PDF with the location of each line. There're a lot of noticeable gaps, but there're also lots of overlapping sections. However, all but of a few of those lines are vanishingly faint in relation to the few prominent lines you might be familiar with. Same thing even with Hydrogen, the least cluttered of spectra; it's very messy in the far violet / near UV range.
Thanks for the link to the NIST site. That saves some work looking up emission lines in my old copy of the CRC Handbook of Chemistry and Physics.
If you want to see this in effect for yourself...get or make yourself a spectrometer for visual observation and some fluorescent objects. For light sources (such as bulbs) too bright for safe or comfortable direct observation, a diffuser of PTFE thread seal tape is perfect -- poor man's Spectralon. Either bounce the light source off a few layers of the tape, or cover the entrance slit of the spectrometer with the tape and point it at the source. You'll see the sharply-defined lines (with the sharpness of the lines depending on the design and quality of the spectroscope), but you'll also faintly see most or even all of the rest of the spectrum. (Of course, this also depends on how well you block out stray light.)
If someone is not very mechanically inclined, I recommend a cheap spectroscope such as the Hand-Held Spectroscope ($10.95) or Pocket Spectroscope ($52.95) on the Educational Innovations (http://educationalinnovations.com). From Edmund Scientifics there is the Spectroscope ($1.95) (http://www.scientificsonline.com/spectroscope.html) or the Desktop Spectronomy Kit ($49.95) (http://www.scientificsonline.com/desktop-spectronomy-kit.html). I have found such devices useful for some color seminars.
So, while quantum mechanics tells us that these effects are quantized and come in neat discreet packages, quantum indeterminacy also tells us that you've got a bit of wiggle room...and the sheer complexity of systems of so many different elements and compounds (just how pure _is_ the mercury vapor in that glass tube?) makes it such that it's very, very hard to ever actually encounter truly monochromatic effects -- and, most of the time, what you get is broadband.
For optical brighteners, this is a good thing. The ideal optical brightener would perfectly balance out the natural gradual drop in reflectivity at the blue end of the spectrum found in most substrates -- which means the most fluorescence at violet and a slow taper to no fluorescence somewhere around yellow, in inverse proportion to the spectrum of the paper. Or, you can go with a coating (with barium sulphate being perhaps ideal) that itself has a flat spectrum without any need for fluorescence, which is what the very best papers do.
...thinking about it, baryta-coated Tyvek might be the ultimate in neutral white papers intended for framing. Any paper manufacturers reading this who want somebody to play with such a paper, give an holler....
Tyvek is also available with an inkjet printer compatible coating, but the company that makes this (I believe it is Dupont) used an FWA in the coating. It has a nice smooth matte surface, but is useless as a white reference. Also, do not over-estimate the usefulness of FWA/OB agents for papers. Due to light exposure and chemical processes these agents can fade rapidly (days to weeks), resulting in a yellowish substrate and rendering their purpose moot. There are some very white (CIECAM02 bc value < 1) papers available on the market. I have a list of papers without FWA/OB agents on my website at http://rmimaging.com/information/fine_art_paper.html. The CIECAM02 J, ac, and bc values for the papers are listed in the table. Robin Myers
On Aug 10, 2014, at 11:24 AM, Robin Myers <robin@rmimaging.com> wrote:
Thanks for the link to the NIST site. That saves some work looking up emission lines in my old copy of the CRC Handbook of Chemistry and Physics.
My pleasure! Don't overlook the option to generate vector-based line identification plots, which you can easily plop as smart objects in Photoshop on top of sample spectra. The tabular data would lend itself well to photorealistic recreations of spectra, if anybody was interested in such.
If someone is not very mechanically inclined, I recommend a cheap spectroscope such as the Hand-Held Spectroscope ($10.95) or Pocket Spectroscope ($52.95) on the Educational Innovations (http://educationalinnovations.com). From Edmund Scientifics there is the Spectroscope ($1.95) (http://www.scientificsonline.com/spectroscope.html) or the Desktop Spectronomy Kit ($49.95) (http://www.scientificsonline.com/desktop-spectronomy-kit.html). I have found such devices useful for some color seminars.
Good options. I'd only note that the technical skills to create a spectroscope are well within the arts-and-crafts abilities of schoolchildren -- but, of course, not everybody has an interest in futzing around with scissors and glue. Plus, an handmade spectroscope is unlikely to be as sturdy as a commercial one unless you put a bit of work into it.
Tyvek is also available with an inkjet printer compatible coating, but the company that makes this (I believe it is Dupont) used an FWA in the coating. It has a nice smooth matte surface, but is useless as a white reference.
Canon sells a Tyvek-backed banner paper with the exact same coating they use for the "Heavyweight Coated" paper they ship with large format printers for initial setup. It's actually superb for its intended purpose. You're right that the coating makes the top side useless as a white reference...but the back side is uncoated. It's got a bit of gloss and texture to it that limits its suitability as a general-purpose photographic white reference to situations with carefully-controlled lighting, but it's only an hair's breadth away from Spectralon in terms of its spectral response. Another great alternative is tear-proof envelope mailers made of Tyvek, available at pretty much any office supply store. It's also a popular material for CD envelopes.
Also, do not over-estimate the usefulness of FWA/OB agents for papers. Due to light exposure and chemical processes these agents can fade rapidly (days to weeks), resulting in a yellowish substrate and rendering their purpose moot.
Oh, no doubt. FWA is about the only thing that makes cheap office paper useable, and Hahnemühle in particular makes some truly fantastic fine art papers with subtle and highly effective applications of FWA; other examples abound across the rest of the spectrum. But, as you note, all these papers have limited lifespans and are not at all suitable for archival work. For something you know only needs to make it though the current season, maybe a bit longer in some cases, FWA is a fantastic option to have available. But if you want your children to see pretty much the same image as you yourself printed, FWA is guaranteed to prevent that.
There are some very white (CIECAM02 bc value < 1) papers available on the market. I have a list of papers without FWA/OB agents on my website at http://rmimaging.com/information/fine_art_paper.html. The CIECAM02 J, ac, and bc values for the papers are listed in the table.
That's a wonderful reference you've put together -- thanks! I'll definitely turn to it the next time I find myself looking for "go-to" papers (which, with luck, won't be for a while, of course). A few notes about some specific papers on that list: Canon's Fine Art Watercolor was, for a while, my absolute favorite paper. With an exception I'll note in a moment, it's got the highest L* value and the most neutral a* value, though the b* makes it slightly yellower than average. More importantly, at least on my iPF8100, it's got the largest gamut of any matte paper I've used. Its biggest downside is a strong tendency to curl. However, several months, maybe an year, ago, it seemed to be out of production. Nobody had any in stock with no indication that more would be on the way. I bought what I thought might have been the last 44" roll on the market. But I see it listed in stock at a couple places today...no clue if they're making it again, if these are the last few rolls from a forgotten shipment, if it's a reformulation, or what. Next, you list Canon's Tyvek Banner as being as close to perfectly white as it gets in the real world. I'll bet you a cup of coffee or other suitable beverage that you got that reading from Canon's swatch book...in which the sample they included lacked the "Heavyweight Coated Paper" coating. If so, grab a sharpie and make a mark on the sample, and you'll see why coating is necessary. Ink -- and especially Canon printer ink (ask me how I know this) spreads and pools on uncoated Tyvek like you wouldn't believe. Still...imagine a formulation of Tyvek with much finer fibers so the grain isn't visible, and a clear inkjet-accepting coating, and you could well wind up with the ultimate for-display fine art paper. It wouldn't have the luxurious feel of an heavy cotton paper, but prints could potentially be spectacular (depending greatly on the coating, of course). On your chart, ignoring canvas and proofing and other specialty papers, it looks like there's a several-way tie for second place, and the Crane Museo Portfolio Rag might have the edge. I can report that it's as good a paper as you can buy. Within rounding, its gamut is the same as the Canon Fine Art Watercolor, though the Canon (assuming it's still the same) might have an imperceptible edge. The Crane feels much better in the hand. The Crane has the same coating on both sides; Crane tech support says this is to control curl and makes no guarantees about what sort of printing the back side is capable of, but I can't see any difference in prints front or back -- and, it de-curls beautifully, unlike the Canon. All together, the Crane is a superior paper to the Canon, except for prints that will be spray-mounted and never handled. Last, I don't notice any of the baryta-coated and similar semigloss papers on your chart. In my experience, save for the Hahnemühle offering, all are OBA-free or have minimal OBA levels, are very bright and neutral, and have excellent gamuts. I've personally settled on the Canson Platine Fibre Rag. Its gamut is just imperceptibly smaller than those of the competitors, but it's perfectly OBA-free...and the paper itself is much more luxurious than anything else and printable on the uncoated side. If you get a chance, you might want to consider adding some of these papers to your guide. Cheers, b&
One more for the world: http://www.bhphotovideo.com/c/product/967078-REG/rotolight_rl_spectra_spectr... 2014-08-16 20:36 GMT+01:00 Ben Goren <ben@trumpetpower.com>:
On Aug 10, 2014, at 11:24 AM, Robin Myers <robin@rmimaging.com> wrote:
Thanks for the link to the NIST site. That saves some work looking up emission lines in my old copy of the CRC Handbook of Chemistry and Physics.
My pleasure!
Don't overlook the option to generate vector-based line identification plots, which you can easily plop as smart objects in Photoshop on top of sample spectra. The tabular data would lend itself well to photorealistic recreations of spectra, if anybody was interested in such.
If someone is not very mechanically inclined, I recommend a cheap spectroscope such as the Hand-Held Spectroscope ($10.95) or Pocket Spectroscope ($52.95) on the Educational Innovations ( http://educationalinnovations.com). From Edmund Scientifics there is the Spectroscope ($1.95) (http://www.scientificsonline.com/spectroscope.html) or the Desktop Spectronomy Kit ($49.95) ( http://www.scientificsonline.com/desktop-spectronomy-kit.html). I have found such devices useful for some color seminars.
Good options. I'd only note that the technical skills to create a spectroscope are well within the arts-and-crafts abilities of schoolchildren -- but, of course, not everybody has an interest in futzing around with scissors and glue. Plus, an handmade spectroscope is unlikely to be as sturdy as a commercial one unless you put a bit of work into it.
Tyvek is also available with an inkjet printer compatible coating, but the company that makes this (I believe it is Dupont) used an FWA in the coating. It has a nice smooth matte surface, but is useless as a white reference.
Canon sells a Tyvek-backed banner paper with the exact same coating they use for the "Heavyweight Coated" paper they ship with large format printers for initial setup. It's actually superb for its intended purpose.
You're right that the coating makes the top side useless as a white reference...but the back side is uncoated. It's got a bit of gloss and texture to it that limits its suitability as a general-purpose photographic white reference to situations with carefully-controlled lighting, but it's only an hair's breadth away from Spectralon in terms of its spectral response. Another great alternative is tear-proof envelope mailers made of Tyvek, available at pretty much any office supply store. It's also a popular material for CD envelopes.
Also, do not over-estimate the usefulness of FWA/OB agents for papers. Due to light exposure and chemical processes these agents can fade rapidly (days to weeks), resulting in a yellowish substrate and rendering their purpose moot.
Oh, no doubt. FWA is about the only thing that makes cheap office paper useable, and Hahnemühle in particular makes some truly fantastic fine art papers with subtle and highly effective applications of FWA; other examples abound across the rest of the spectrum. But, as you note, all these papers have limited lifespans and are not at all suitable for archival work. For something you know only needs to make it though the current season, maybe a bit longer in some cases, FWA is a fantastic option to have available. But if you want your children to see pretty much the same image as you yourself printed, FWA is guaranteed to prevent that.
There are some very white (CIECAM02 bc value < 1) papers available on the market. I have a list of papers without FWA/OB agents on my website at http://rmimaging.com/information/fine_art_paper.html. The CIECAM02 J, ac, and bc values for the papers are listed in the table.
That's a wonderful reference you've put together -- thanks! I'll definitely turn to it the next time I find myself looking for "go-to" papers (which, with luck, won't be for a while, of course).
A few notes about some specific papers on that list:
Canon's Fine Art Watercolor was, for a while, my absolute favorite paper. With an exception I'll note in a moment, it's got the highest L* value and the most neutral a* value, though the b* makes it slightly yellower than average. More importantly, at least on my iPF8100, it's got the largest gamut of any matte paper I've used. Its biggest downside is a strong tendency to curl. However, several months, maybe an year, ago, it seemed to be out of production. Nobody had any in stock with no indication that more would be on the way. I bought what I thought might have been the last 44" roll on the market. But I see it listed in stock at a couple places today...no clue if they're making it again, if these are the last few rolls from a forgotten shipment, if it's a reformulation, or what.
Next, you list Canon's Tyvek Banner as being as close to perfectly white as it gets in the real world. I'll bet you a cup of coffee or other suitable beverage that you got that reading from Canon's swatch book...in which the sample they included lacked the "Heavyweight Coated Paper" coating. If so, grab a sharpie and make a mark on the sample, and you'll see why coating is necessary. Ink -- and especially Canon printer ink (ask me how I know this) spreads and pools on uncoated Tyvek like you wouldn't believe.
Still...imagine a formulation of Tyvek with much finer fibers so the grain isn't visible, and a clear inkjet-accepting coating, and you could well wind up with the ultimate for-display fine art paper. It wouldn't have the luxurious feel of an heavy cotton paper, but prints could potentially be spectacular (depending greatly on the coating, of course).
On your chart, ignoring canvas and proofing and other specialty papers, it looks like there's a several-way tie for second place, and the Crane Museo Portfolio Rag might have the edge. I can report that it's as good a paper as you can buy. Within rounding, its gamut is the same as the Canon Fine Art Watercolor, though the Canon (assuming it's still the same) might have an imperceptible edge. The Crane feels much better in the hand. The Crane has the same coating on both sides; Crane tech support says this is to control curl and makes no guarantees about what sort of printing the back side is capable of, but I can't see any difference in prints front or back -- and, it de-curls beautifully, unlike the Canon. All together, the Crane is a superior paper to the Canon, except for prints that will be spray-mounted and never handled.
Last, I don't notice any of the baryta-coated and similar semigloss papers on your chart. In my experience, save for the Hahnemühle offering, all are OBA-free or have minimal OBA levels, are very bright and neutral, and have excellent gamuts. I've personally settled on the Canson Platine Fibre Rag. Its gamut is just imperceptibly smaller than those of the competitors, but it's perfectly OBA-free...and the paper itself is much more luxurious than anything else and printable on the uncoated side. If you get a chance, you might want to consider adding some of these papers to your guide.
Cheers,
b&
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Hello Mr. Goren, <snipped>
Tyvek is also available with an inkjet printer compatible coating, but the company that makes this (I believe it is Dupont) used an FWA in the coating. It has a nice smooth matte surface, but is useless as a white reference.
Canon sells a Tyvek-backed banner paper with the exact same coating they use for the "Heavyweight Coated" paper they ship with large format printers for initial setup. It's actually superb for its intended purpose.
I think you will find that Dupont makes the Tyvek inkjet paper for all of the companies that resell it.
You're right that the coating makes the top side useless as a white reference...but the back side is uncoated. It's got a bit of gloss and texture to it that limits its suitability as a general-purpose photographic white reference to situations with carefully-controlled lighting, but it's only an hair's breadth away from Spectralon in terms of its spectral response. Another great alternative is tear-proof envelope mailers made of Tyvek, available at pretty much any office supply store. It's also a popular material for CD envelopes.
One big problem with Tyvek papers, such as shipping envelopes, CD sleeves, etcetera, is that the translucency of the paper varies considerably across its surface. It requires several layers to get a consistent translucency, but there is still the fiber density variation. The fiber variation creates color consistency issues due to the refraction of light through the fibers.
Also, do not over-estimate the usefulness of FWA/OB agents for papers. Due to light exposure and chemical processes these agents can fade rapidly (days to weeks), resulting in a yellowish substrate and rendering their purpose moot.
Oh, no doubt. FWA is about the only thing that makes cheap office paper useable, and Hahnemühle in particular makes some truly fantastic fine art papers with subtle and highly effective applications of FWA; other examples abound across the rest of the spectrum. But, as you note, all these papers have limited lifespans and are not at all suitable for archival work. For something you know only needs to make it though the current season, maybe a bit longer in some cases, FWA is a fantastic option to have available. But if you want your children to see pretty much the same image as you yourself printed, FWA is guaranteed to prevent that.
There are some very white (CIECAM02 bc value < 1) papers available on the market. I have a list of papers without FWA/OB agents on my website at http://rmimaging.com/information/fine_art_paper.html. The CIECAM02 J, ac, and bc values for the papers are listed in the table.
That's a wonderful reference you've put together -- thanks! I'll definitely turn to it the next time I find myself looking for "go-to" papers (which, with luck, won't be for a while, of course).
I am glad it is of use.
A few notes about some specific papers on that list:
Canon's Fine Art Watercolor was, for a while, my absolute favorite paper. With an exception I'll note in a moment, it's got the highest L* value and the most neutral a* value, though the b* makes it slightly yellower than average. More importantly, at least on my iPF8100, it's got the largest gamut of any matte paper I've used. Its biggest downside is a strong tendency to curl. However, several months, maybe an year, ago, it seemed to be out of production. Nobody had any in stock with no indication that more would be on the way. I bought what I thought might have been the last 44" roll on the market. But I see it listed in stock at a couple places today...no clue if they're making it again, if these are the last few rolls from a forgotten shipment, if it's a reformulation, or what.
Next, you list Canon's Tyvek Banner as being as close to perfectly white as it gets in the real world. I'll bet you a cup of coffee or other suitable beverage that you got that reading from Canon's swatch book...in which the sample they included lacked the "Heavyweight Coated Paper" coating. If so, grab a sharpie and make a mark on the sample, and you'll see why coating is necessary. Ink -- and especially Canon printer ink (ask me how I know this) spreads and pools on uncoated Tyvek like you wouldn't believe.
You are correct, the papers listed on my site were measured from paper samplers. To purchase a small pack of each paper type for dozens of papers would require some deep pockets and ones without the holes I often find in mine. The Tyvek Banner paper may have its best use for offset or silk screen printing. As for checking papers for the highest L* value, I would like to suggest that you should check a paper for its L* value unprinted, and also for its L* value when printed with solid black. This will establish the paper's lightness range which will have a big effect on the gamut. You might find a paper with a high L* but the black might be much lighter than a paper with a slightly lower L* yet makes a very dense black, thus making the L* range much larger.
Still...imagine a formulation of Tyvek with much finer fibers so the grain isn't visible, and a clear inkjet-accepting coating, and you could well wind up with the ultimate for-display fine art paper. It wouldn't have the luxurious feel of an heavy cotton paper, but prints could potentially be spectacular (depending greatly on the coating, of course).
I would like to get a Tyvek paper with smooth surface without titanium dioxide and fluorescent whitening agents. If you find any please let me know. I would owe you a large frosty adult beverage.
On your chart, ignoring canvas and proofing and other specialty papers, it looks like there's a several-way tie for second place, and the Crane Museo Portfolio Rag might have the edge. I can report that it's as good a paper as you can buy. Within rounding, its gamut is the same as the Canon Fine Art Watercolor, though the Canon (assuming it's still the same) might have an imperceptible edge. The Crane feels much better in the hand. The Crane has the same coating on both sides; Crane tech support says this is to control curl and makes no guarantees about what sort of printing the back side is capable of, but I can't see any difference in prints front or back -- and, it de-curls beautifully, unlike the Canon. All together, the Crane is a superior paper to the Canon, except for prints that will be spray-mounted and never handled.
Some of the papers listed are no longer available and some are now made by other companies. For instance, the Crane Museo Portfolio Rag, which I use for many projects, is no longer made by Crane but by IntelliCoat Technologies. In making the transition the thickness changed from 15 mil to almost 20 mil, although the color characteristics remained the same. Crane sold their entire digital fine art media line to IntelliCoat after I made the measurements.
Last, I don't notice any of the baryta-coated and similar semigloss papers on your chart. In my experience, save for the Hahnemühle offering, all are OBA-free or have minimal OBA levels, are very bright and neutral, and have excellent gamuts. I've personally settled on the Canson Platine Fibre Rag. Its gamut is just imperceptibly smaller than those of the competitors, but it's perfectly OBA-free...and the paper itself is much more luxurious than anything else and printable on the uncoated side. If you get a chance, you might want to consider adding some of these papers to your guide.
The baryta papers were not in the samplers, hence their exclusion from the list. If I can get samplers with baryta papers you can be assured I will add them to the appropriate lists. Also, as I get newer samplers I continue to add new papers to the list. If you have any particular papers you would like added, let me know and I will contact the manufacturers for samples. Regards, Robin Myers
participants (4)
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Ben Goren
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Ernst Dinkla
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José Ángel Bueno García
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Robin Myers