Ink Formulations (water vs. solvent?)

[thorkil]

Just wondering about what is in some of my inks...I read in another thread about some having trouble with dried ink not being waterproof. In other words, a damp hand will smear it. I think the vintage inks I usually use are based on some kind of solvent. When dry, they stay put.
Contrary to the belief of a lot of people on the 'bay, adding water to dried ink powder lying on the bottom of a vintage bottle will not produce ink.You get colored water, which ripples the paper, is the wrong color, and is generally unsatisfactory. So, the old inks (by Waterman, Sheaffer, Parker, Sanford) must be solvent based?

Just wondering if anybody knows....

[elaineb]

Generally, inks are made from these ingredients:

(1) Dye dissolved in water
(2) A binder, like gum arabic, to adhere the dye to the page after the water has evaporated
(3) A humectant, like glycerine or propylene glycol, that retards water evaporation to keep the ink flowing through the tiny ink channels in feed and nib before it hits the paper. Humectants also increase the viscosity of the ink
(4) A surfactant (i.e. detergent) that also aids in the flow of the liquid down the feed and nib.
(5) Preservative of some sort, to prevent the ink from spoiling through microbial growth

I don't know what Parker did for it's special quick dry "51" and "Durachrome" inks during those periods, but generally speaking, solvents are not part of standard fountain pen ink formulations. (This is coming from research I've done to formulate my own inks. Information isn't easy to come by, as much information is kept proprietary by most companies.) I suspect a lot of companies use small amounts of additional additives, such as alcohol, to aid with specific problems. But I don't think there are any fountain pen inks made mainly with solvents.

The smearing of dried ink on the page sometimes has to do with the amount of dye used vs. the amount of gum arabic used. If insufficient binder is used, then the dye powder won't be securely "glued" to the paper and will readily come off from the slightest touch of moisture. Unfortunately, if you increase the amount of binder to compensate for increased dye saturation, it can have a negative effect on the writing properties of the ink. It can become dry, stubborn, and unpleasant to use.

Smearing can also happen if you use a lot of glycerine/humectant in a formulation to provide that nice "lubricated" feel under the nib. Dried glycerine on a page will eagerly dissolve at the slightest touch of moisture on your skin, bringing the dye color with it. Gum arabic can mediate that to some extent, but any amount of humectant reduces gum arabic's water resistance. So if you pour in a ton of gum arabic, then you get back into the flow problems mentioned above.

Making a decent fountain pen ink is a difficult task, because every dye when dissolved in water has unique physical qualities. And the more saturated the dye solution, the more persnickety its physical qualities become. The task of tweaking this liquid into the perfect balance of flow, lubrication, adhesion, and permanency can be really tough. A formulation that dries into a perfect ink on the paper might be impossible to write with, and a beautiful free-flowing ink might feather or bleedthrough or wrinkle the paper, or come off on your hands, or dry into a muddy ugly mess.