Silver coat - strongly reflects light when you need to bring out contrast from exposure. Golden coat - reduces the color temperature of light when you need to warm and soften the frame. White coat - illuminates with bright, neutral color light when the amount of natural light is not enough. Black coat - reduces reflections and deepens shadows, improves depth in photos with a small tonal range, absorbs light when natural light or in the studio is too sharp. Diffusion coat - disperses and softens the light, acts as a softbox.