Why Are Liquid Handmade Watercolors Not Stored in Completely Airtight Containers?

Long-term storage experiments led to new material observations

During the long-term production of handmade watercolors, different storage methods for liquid materials have been documented over extended periods, including storage in completely airtight containers.

As storage time increased, long-term observations showed that liquid materials continued to change even while sealed inside closed containers.

These observations gradually influenced the long-term storage methods adopted during production.

Gas accumulation was observed inside completely sealed containers

During long-term storage experiments, some liquid paint samples gradually developed noticeable gas accumulation after remaining in completely sealed containers for an extended period.

As storage continued, increasing internal pressure was observed in some containers. In several cases, visible signs of container expansion were also documented.

These observations indicate that material changes can continue while the paint remains in its liquid state, and any gases produced during this process may accumulate when they cannot escape from a completely sealed container.

Long-term storage favors allowing controlled gas release

Based on current long-term material observations, storage that allows a controlled path for gas release has proven to be more consistent with the observed behavior of this material system than completely airtight storage.

When gases produced during storage are able to dissipate gradually, they are less likely to accumulate inside the container, reducing the continued increase in internal pressure.

For this reason, completely airtight storage is no longer used as the preferred long-term storage method for liquid handmade watercolors within this material system.

These observations apply only to the liquid stage

The observations described here apply specifically to handmade watercolor paints before filling, while the material remains in its liquid state.

Once the paint has completed its natural drying process, the material system changes substantially, and different long-term storage conditions become appropriate for solid watercolor pans.

For this reason, the liquid and solid stages are documented separately within the long-term material archive.

Long-term material observation continues

The current understanding of long-term storage behavior in liquid handmade watercolors is based on continuous production records and storage experiments.

As additional colors, longer observation periods, and new material systems continue to be documented, the understanding of liquid storage behavior will continue to expand and become part of the ongoing long-term material archive.