Recommendations for the Long-Term Storage of Handmade Watercolor Paints

Even after drying, the surrounding environment remains part of the material behavior

With the completion of natural drying, the development of the material does not come to an end. Observations during storage under various environmental conditions show that humidity, temperature, and air circulation continue to affect the surface shape, internal structure, and overall stability of handmade paints. Storage is therefore not a static end point, but a continuation of long-term material observation. The following notes are based on ongoing tracking of different formulation systems. They serve as general guidance and do not represent rigid rules.

• An environment as dry as possible supports long-term storage

  Air humidity remains a very active environmental variable even during storage. In permanently high humidity, certain formulation systems continuously absorb moisture from the air. Practical observations show that this alters surface texture, softens paint pans, and, under very high humidity, can increase the risk of microbial growth. Keeping the environment as dry as possible helps slow down these physical changes significantly.

• Outdoor storage is generally avoided

  Outdoor environments are subject to strong and unpredictable fluctuations. Dew, rain, condensation, and day-night temperature changes expose the material to continuously high moisture loads. Storage and related observations of handmade watercolor paints are therefore conducted indoors; permanent outdoor storage is not recommended.

• Direct sunlight and high temperatures should be avoided where possible

  Temperature also directly affects the condition of the material. Long-term observations show that specific formulations—especially those containing honey—are more prone to drying cracks, fine fissures, or local surface breaks under persistent heat or direct sunlight. A cool storage location away from direct sunlight provides a much more stable foundation for storage.

• The storage container should also remain clean and dry

  Not only the paints themselves, but also their immediate micro-environment plays a role. Practical observation shows that leftover moisture or dust inside paint boxes or plastic containers can indirectly affect the condition of the paints. Keeping containers clean and dry is a fundamental measure to reduce unwanted environmental influences.

• A small gap between paints can be helpful

  Some formulations are very sensitive at the surface to ambient humidity. Observation records show that honey-based watercolor paints can become slightly sticky on the surface again during humid weather. If individual paint pans lie tightly against one another, surface contact and slight sticking may occur. Maintaining a small gap between individual pans reliably prevents this direct contact.

• Regular checking supports long-term material observation

  Storage itself is part of observation. During use or re-sorting, the condition of the paints can be checked occasionally. It is worth taking a look at surface texture, firmness, unusual odors, or signs of mold growth. Frequently used colors are naturally observed during normal re-wetting; for rarely used shades, checking at longer intervals is recommended.

A stable storage environment supports long-term material stability Long-term data shows that environmental influences accompany the entire lifecycle of handmade watercolor paints—from formulation and production to storage. A dry, cool indoor environment protected from sun significantly lowers the risk of unexpected material changes. Because different pigment and binder combinations react differently to their environment, storage behavior remains an important part of the documentation in the Pigment Behavior Archive.