The other day, I was choosing an ink and noticed that some of the inks had formed condensation inside the bottle while others did not. I came to realize that only the bottles containing document inks had condensation. All my document inks are manufactured by De Atramentis (handmade German inks), yet the non-document De Atramentis inks did not develop condensation. Why?
Inks are just inks – right?
WARNING! Things are going to get geeky. If that is not your thing simply skip down to the Conclusion.
But how do I solve this? Research my boy!
Condensation is the process of water vapor turning back into liquid water. It can happen in one of two ways: (1) water vapor is either cooled to its dew point or (2) the air becomes so saturated with water vapor that it can’t hold more water.
Inks come in a variety of types, I set about determining what type is De Atramentis Document ink. Results are inconclusive and De Atramentis is silent on the matter. This means the document ink can be one of two types:
- Pigment-based inks contain larger particles that are suspended in the water rather than dissolved in it.
- Cellulose-Reactive (Bulletproof) Ink is Dye-based ink with cellulose-reactive chemistry to bond the dyes to the cellulose fibers in the paper – the ink stains the paper.
Pigment-based inks are not water soluble thus diffusing the ink particles into water-base. The random motion of the water causes the particles to move in random directions. This causes the particles to disperse throughout the water until equilibrium (saturation) is reached. Then molecular vibration called Brownian Motion keeps the particles in suspension.
“The kinetic energies of the molecular Brownian Motions, together with those of molecular rotations and vibrations, sum up to the caloric component of a fluid’s internal energy (the equipartition theorem). At a certain temperature, the particles in a liquid have enough energy to become a gas aided by the atmospheric pressure on the liquid.” ~ Wikipedia
“The British scientist James Clerk Maxwell and the Austrian physicist Ludwig Boltzmann, in the 19th century, establish the kinetic theory of gases. The simplest kinetic model is based on the assumptions that: (1) the gas is composed of a large number of identical molecules moving in random directions, separated by distances that are large compared with their size; (2) the molecules undergo perfectly elastic collisions (no energy loss) with each other and with the walls of the container, but otherwise do not interact; and (3) the transfer of kinetic energy between molecules is heat.” ~ Britannia
Conclusion (aka how I see it)
In my mind, these Document inks are pigment-based on the mechanics of diffusion. While Brownian Motion introduces sufficient kinetic energy (aka heat) aided by the reduced atmospheric pressure associated with an elevation of 6,700 feet reducing the ink surface tension, thus making evaporation easier. During evaporation, the water molecules gather in the area above its surface since that area is confined within a bottle. The pressure exerted by the accumulating molecules increases resulting in spontaneous condensation. The non-document inks lack the added kinetic energy of Brownian Motion meaning minimal evaporation and thus no condensation.
- Britannia: Kinetic Theory of Gases
- Wikipedia: Brownian Motion