Re: Phosphors
Re: Phosphors
- Subject: Re: Phosphors
- From: Robin Myers <email@hidden>
- Date: Sat, 16 Aug 2014 14:40:47 -0700
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
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