Generally, pigments are not soluble in water. However, there are exceptions.
Types of Pigments and Water Solubility
The solubility of a pigment in water depends heavily on its chemical composition. Many pigments are insoluble in water, oil, and other common solvents. To use these pigments, they must be finely ground and mixed with a dispersing agent or vehicle. This is the case for many common pigments used in paints and other applications, as evidenced by sources like Goldwell (https://www.goldwell.com/en-us/education/hair-science/color-theory/dyes-and-pigments/) and Winsor & Newton (https://www.winsornewton.com/blogs/guides/difference-between-dyes-pigments). These sources clearly state that pigments are generally insoluble.
However, some pigments are water-soluble. For example, anthocyanins are a class of water-soluble pigments found in many plants, responsible for their vibrant colors (https://pmc.ncbi.nlm.nih.gov/articles/PMC5613902/). Other water-soluble pigments can be derived from fungi, as explored in research focusing on biotechnological production of natural food colorants (https://pubmed.ncbi.nlm.nih.gov/15831392/, https://www.sciencedirect.com/science/article/pii/S0958166905000364, https://pubmed.ncbi.nlm.nih.gov/20806258/). These examples highlight that the water solubility of pigments is not a universal property.
Lake pigments offer another example. While derived from dyes (which are soluble), the process of making lake pigments renders them insoluble in water (https://rebeccadesnos.com/blogs/journal/making-lake-pigments/).
Key Differences: Dyes vs. Pigments
It's crucial to differentiate between dyes and pigments. Dyes are soluble and dissolve into the material they color, while pigments are insoluble and remain as discrete particles. This distinction is fundamental in understanding their behavior with water (https://justpigments.com/pages/are-your-dyes-and-pigments-water-or-oil-dispersible).
