PAPEL PIEDRA/STONE PAPER

ON “STONE PAPER”

Since the late 90ies, there is a new paper called "Stone Paper" that uses no tree-derivatives and is -allegedly- more ecological than regular paper made from wood-pulp.

This new product was first developed by the Lung Meng Tech Co., in Taiwan and is marketed under several trade names around the world.

I used for testing a small notebook by Miquelrius (a Catalan company) that is linked to Emana Green, a multinational company with offices in Taiwan and New York.

The sheets of this notebook are 240 grs/m². If it were regular wood-pulp paper, this would indicate a thickness of cardboard. But, in this paper everything is a bit different. It feels (when pinched between one´s fingers) as if it were a 120 grs/m² paper (at the most).

The fact that it uses "mineral powder" (calcium carbonate, a waste material collected from limestone), is what makes it 60% heavier than regular paper.

There are several companies producing Stone Paper and the formulations vary a lot between different brands. But, let´s say that it is made of 70-80% of mineral powder and 30-20% of non-toxic resin.

For instance, Fiberstone claims to use no water, no tree-derivatives and no bleach into the manufacturing process. Oxford uses limestone and polypropylene. Other brands inject tree-fibers between coats of clay, or use recycled paper mixed with the mineral powder.

The resin used to bond the mineral powder is commonly high-density polyethylene. So, one can consider this stuff like a sort of "bio-plastic paper."

The bad thing is that this stuff is not biodegradable. It needs to be recycled into plastic or paper. 

However, it is photodegradable. The brand Terraskin claims that their paper will begin to degrade after 6 to 9 months of exposure to humidity and direct sunlight.

Basic properties:

It collects no static charge, is acid-free with a neutral PH value, has no grain, is water, grease and insect resistant, and tears with difficulty due to a latex-like texture. Having no grain, Stone Paper possesses a smoother surface than traditional paper-products, obviating the need for a coating or gloss. It burns cleanly and does not produce toxic fumes. It is compatible with inkjet or solid-ink printers, but does not respond well to the high temperatures generated by laser-printers.

It folds in a similar way to regular paper, but it makes evident there is a plastic-content into it. The matt surface will become glossy if you rub it with the flat-surface of your nail or with a hard tool. 

I did a short first test of this "Stone-Paper" by using a regular ballpoint, a permanent marker (Staedtler "Lumocolor") and a speedball (Pilot "G-Tec-C4," 0.4mm point). These three types of writing instruments perform wonderfully upon this surface. Then, I used a regular mechanical pencil (0.7 lead). It also worked well. If you carve some lines with your fingernail, the material gets “etched,” showing a very clear level-differentiation. This effect is more accentuated than with regular paper. So, the pencil and the ballpoint-tip also tend to produce some etching-effect.

Then, I tested it with fountain-pens. First of all, one does notice a difference in "traction" (pulling along). I mean that the friction of the tip of the nib on the surface is higher than with natural paper. This has nothing to do with the roughness of the surface, which is truly smooth (like that of a regular satin-finish paper). It has to do with the nature of the bonding resin, which gives a rubber-feel to the surface.

“EF” and “F” nibs perform better, in my opinion, than “M,” “B” or Italics. This is because fountain-pen ink tends to feather lots more on Stone Paper than on a regular satin-finish wood-pulp paper. This feathering did not happen with the speedball-ink or with the permanent-marker (fine nylon-tip), which are alcohol-based inks. The sheet of Stone Paper did not show any “bleedthrough” on the reverse when using any of the mentioned inks. Zero “ghost effect,” either. Not even with a wet “BB” or with a 1.1mm Italic. But, with these wider tips, the bigger amount of ink tends to feather a lot and also dries a bit slower than on regular paper.

My conclusion is that, if using a fountain-pen, Stone Paper is more suitable for “F” nibs. But, if you write fast and apply too much pressure, you are prone to catch a shaving of the material between the tines. So, crosstrokes are prone to shaving and downstrokes feel smoother. This shaving is much less likely to happen with a “B” nib, but then there is the mentioned feathering factor. A sharp “EF” nib will tend to catch a lot on this paper. Same about a sharp Italic for calligraphy.

I made writing tests on Stone Paper with Iroshizuku “Momiji,” Waterman “Turquoise,” Diamine “Asa Blue” and Lamy “Blue-Black.” All these inks do feather (to a certain degree) on this paper. The feathering was always less pronounced when using “F” nibs and more pronounced using “B” or Italic nibs. The less feathering was achieved with the water-resistant ink Lamy “Blue-Black.”

Not a single one of these particular inks does feather on Clairefontaine 90grs Velouté (my favorite paper). I´m not saying there are no FP-inks out there which won´t feather at all on Stone Paper, but -after my tests- I conclude that most FP-inks will experience more feathering on this paper than on most wood-pulp papers which have a satin finish. Evidently, on a watercolor paper the feathering would be always major.

Stone Paper tends to embed the ink in a different way to fibers of regular papers. So, there is a slight more permanence of the traces when water is rubbed on top of the writing. But, when water remains for a few minutes on top of the writing, it does vanish completely.

Rubbing the writing with water produces a lot of smearing of the ink, especially on traces produced by a “B” or by an Italic nib. But, some slight traces of the writing do stay, when on a regular paper the trace would be a bit more intensely washed out. Of course, I am referring now to inks which are not water-resistant. In the case of the Lamy “Blue-Black” (a water-resistant ink), there is little difference on the effect of water-rubbing or smearing between both papers (Clairefontaine & Stone Paper).

The water-resistance of Stone Paper is the most underlined property by the manufacturing companies. It won´t crumble if exposed to water. Equally it will protect the writing under the effects of water, especially when using ballpoints, speedballs or water-resistant ink for fountain-pens. Also, it requires more force to tear than regular paper.

Most of the information of this article, about the manufacturing companies of Stone Paper and its composition, was excerpted from Wikipedia and from the websites of the mentioned manufacturing companies.

John Puig

June 2013