Yes, your Artiste-Clad Hammered Copper cookware will naturally darken or tarnish over time. Based on your preference, you may choose to either maintain the patina or restore the shine on your pan's exterior. Neither will affect your pan's performance.
To clean and restore the pan's shiny appearance, use the Lagostina Stainless Steel and Copper Cleaner. Apply with a clean, wet cloth or sponge, rubbing in a circular motion. Then, rinse in warm water, and dry thoroughly with a clean, soft cloth.
To clean and maintain the patina, wash the pan in warm, soapy water with a soft cloth or sponge. Then, rinse in warm water, and dry thoroughly with a clean, soft cloth.
DO NOT use a powder cleanser, bleach, oven cleaners, steel wool, steel scouring pads, nylon pads, harsh detergents, or detergents containing chlorine bleach to clean your pan's exterior. Because copper is a soft metal, this could damage the pan's appearance.