Describe the role of mordants in natural dyeing processes and their impact on colorfastness and color intensity.

Mordants are substances used in natural dyeing processes to fix dyes onto textiles and improve colorfastness and color intensity. They work by forming coordination complexes with the dye molecules, allowing them to adhere more firmly to the fabric and resist fading or washing out. Common mordants include alum, iron salts, and tannic acid, each of which produces different effects on the final color and properties of the dyed material. Mordants also play a crucial role in modifying and enhancing the hues and shades of natural dyes, expanding the range of colors achievable in textile dyeing.