Observations on Gravity, Pigment Concentration, and Reflow in Unstable Volatile Ink Systems

In long-term observation records of unstable volatile ink systems, fluid movement is never a one-way progression. After the ink completes its initial spreading, movement, or direction changes on the surface, it frequently moves back toward areas it previously passed through. This behavior of re-covering or re-entering previously formed areas is recorded as "reflow." In long-term records, reflow is not an occasional accidental event, but one of the continuously repeating phenomena within the material behavior system.

Gravity continuously participates in the liquid's movement process and influences the development direction of the ink. In archived observations, gravity and reflow phenomena frequently appear at the same time. However, the influence of gravity does not mean that the development path is completely fixed. In actual records, factors such as surface tilt, substrate condition, direction adjustments, and heat application alter the path and speed of reflow. For example, when a heat tool moves continuously, the boundary position, development speed, and local direction of certain reflow areas show corresponding adjustments; meanwhile, when the working surface is tilted, areas that were originally prone to reflow may show no obvious visible tracks.

The state of the liquid directly affects how reflow manifests. Thicker fluid layer areas are more likely to exhibit noticeable reflow and continue to influence subsequent changes across a wider area; in contrast, reflow phenomena in thinner fluid layers are generally weaker.

At the same time, liquid pigment concentration shows a strong correlation with reflow speed—liquids with lower pigment concentrations typically possess stronger fluid mobility, resulting in faster movement and reflow speeds; liquids with higher pigment concentrations exhibit a relatively slower pace of development.

The occurrence of reflow is often accompanied by the covering and reshaping of existing structures. When liquid re-enters a previously formed area, the original structure undergoes coverage, shift, or secondary changes. However, in numerous records, coverage does not mean that early marks completely disappear; parts of the original structure still retain base traces and exist together with the newly entering liquid within the same area.

As the reflow activity gradually slows down, the system enters a subsequent development stage. At this point, although the liquid slows its macro-movement, evaporation and deposition processes continue. Pigment particles in the ink gradually deposit as fluid mobility weakens, altering the appearance and structural features of local areas. Under specific formulations and special conditions involving multiple coexisting variables, reflow occasionally forms critical structures that are difficult to replicate stably; these phenomena are likewise preserved in the archives as independent observation records.

During a single formation process, different areas often display unsynchronized development states: some areas are undergoing noticeable reflow adjustments, adjacent areas may maintain their original spreading paths, and other areas are generating new deposition boundaries. These local changes together form a complete record of the dynamic evolution of the ink system.