The term 'CALLIGRAPHER's Fluids' refers to the INKS used by calligraphers. Calligraphers use a variety of INKS to create beautiful lettering and artwork. INKS are available in a range of colors, from traditional black to vibrant hues. They can also be mixed to create custom shades. Calligraphers often use special tools to apply the INKS, such as brushes, pens, and quills. The INKS are usually water-based, but some are oil-based.