Answer:
The size of the particle has a color effect in Rayleigh scatter, but that is unrelated to your question. In the visible spectrum, the main factor determining the color is electronic transitions in the atoms and molecules which make up the substances.
For very simple compounds, it is relatively easy to determine the absorption bands. The bands could possibly change in solution because the electrical environment of the compound’s molecules could change while in solution with water’s polar molecules. However, in many cases, the bands only change slightly so that a purple crystal for example might remain a purple color in aqueous solution.
Some compounds are very sensitive to ionization and to the pH of the aqueous solution, and for these compounds you may see large color shifts as they go into solution.