Posted in Ink, Stories

WHAT! All inks are not created equal?

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.
Dye-Based (left) & Document Ink (right)

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 Science

“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.

Reference Material



I'm a loser as my wife likes to tell me, I enjoy researching dead cousins and playing with fountain pens.

11 thoughts on “WHAT! All inks are not created equal?

  1. Seriously, thank YOU for making easy for us to understand. Fascinating as it is, it had to be put simply, and you managed to do exactly that. Thanks! Grear post. Vic (from PORTUGAL…).

    Liked by 1 person

  2. Great research. A few reads of this are required. I like your ever seeking mind. I never notice condensation in my few ink bottles, only bubbles on shaking! But then I only have other well known standard fountain pen inks and India inks. No Atramentis, either document or ‘the other’, inks to use in fountain pens whatsoever. Be good to try some after reading this. Do you use it in your vintage pens? Be good to know before buying. Thanks for the knowledge.

    Liked by 1 person

    1. LOL, Gray just a few reads. You should have read the first draft, which was over 1000 words. I wrote it and had no idea what I said. I use their inks in all my pens, no ill effects. I primarily purchase their document inks for watercolor sketching as they are waterproof. As with all inks, thorough cleaning of the pen is recommended.

      Liked by 1 person

      1. First draft sounds like a ready for suitable appropriate magazine post. 😊 I will try the ink then. When I bought the Montblanc recently he said he was washing out the pen with Monteverde flush and then leaving overnight in distilled water before he sent it to me. I know the Hard Rubber advice you gave way back when re: water contamination. So wouldn’t do that on some. I don’t do watercolour to any great degree so will choose some other choice from their range. Thanks for the advice. All the best.

        Liked by 1 person

      2. I have never used a flush before, maybe with a pigment ink I should. I simply remove the nib and feed for a good cleaning. If there will be issues it will be there. Again, never soak a hard rubber pen in water. Very bad things can happen.

        Liked by 1 person

      3. I used a flush clean on the Rotring Graphos pens with the Rotring cleaner. That worked well. The others are a quick water wash out as if taking in ink. I am really tentative re: feed removal on some of the vintage ones I own. Need a knockout block and appropriate hammer too really. Thanks Danny.

        Liked by 1 person

      4. Too right about leaving it alone. ‘If it ain’t broke don’t fix it’ is another one too. I have changed about four or five ink sacs now. But every one had a feed that felt firmly in place. Too in place to take chances. Luckily so far, a gentle blowing through the feed produced the feel of air on the hands. They’ve all responded okay when inked up. I would consider a cleaner if one was compromised though. The Rotring cleaner fluid got rid of the dried on stuff seen on the Graphos ‘cartridge’ ink holder walls quite effectively. Thanks for the advice.

        Liked by 1 person

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