Specific gravity of ink and color rendering of prints:

Ink specific gravity serves as an overall measure of the specific gravity of the main components of ink, namely pigments, fillers and binders. In general, when combining two inks of different specific gravities for color printing, the greater the specific gravity of the ink, the greater the quantity needed, and vice versa. Additionally, mixing multiple inks of varying specific gravities in color printing may result in layering due to sedimentation, which may cause color variation or uneven color rendition during the printing process. The ink may separate, with the lighter components floating to the top. For example, when green ink is combined with lead chrome yellow and peacock blue ink, the ink with the lower specific gravity may rise to the surface over time, while the ink with higher specific gravity dense flows, resulting in what is called "color floating". Therefore, it is crucial to mix the prepared ink well before pouring it into the ink fountain.

Ink concentration and color rendering of prints:

The concentration of the ink, also called the coloring strength of the ink, reflects the degree of dispersion of the ink and the pigment content in the ink. Factors such as pigments, bonding materials, fillers and additives influence ink concentration. In general, the higher the degree of dispersion of the pigments, the higher the concentration of the ink; conversely, the higher the pigment content in the ink, the higher the concentration of the ink.

As the concentration of the ink increases, the consistency of the ink gradually thickens. Therefore, the concentration of the ink determines the shade of the ink. When the ink concentration is high, the printed shade is darker, the amount of ink consumed during printing is relatively small, and the color quality of the ink is higher.