Viscosity is a measure of a liquid’s ability to resist flow. A thick liquid that does not flow easily has high-viscosity; a thin liquid that readily flows has low-viscosity. The impact of a low viscosity ink is writing smoothness. Below is a quick overview of the advantages and disadvantages of using low viscosity inks.


  • Less pressure needs to be applied to the pen to have it write cleanly. This permits holding the pen with less stress on the hand, saving energy and improving comfort. This can also translate to quicker writing speeds.
  • The inks usually have a greater range of colors.
  • They tend to write finer lines and more clearly.


  • More likely to smudge due to longer dry time.
  • More likely to “bleed” through the paper due to its absorption into the paper.
  • Generally run out of ink more quickly as more ink is flowing through the nib.

Low viscosity inks are generally found in rollerball or gel pens, where as a high viscosity oil-based ink is generally found in ballpoint style pens where dry time is more critical than smoothness.
Emulsion Ink

As a company rich in ink innovation, Zebra’s Emulsion Ink is a reflection of its continual effort to enhance and evolve what is already quite good.

We recognize that writing smoothness is of great importance to most consumers. When they are not using technology and are required to put pen to paper they want their writing experience to be effortless; they want the writing instrument to glide across the paper.

Zebra’s Emulsion Ink Technology is the premium in effortless writing performance, providing a superbly smooth writing experience. Emulsion Ink provides more ink flow than other inks for fluid luxurious strokes covering a broad area. It is the smoothest pen currently available on the market.