https://www.creativelive.com/class/understanding-light-light-modifiers-mark-wallace

What’s the difference between a large silver umbrella and a small softbox? Why use a grid? How do you control light spill? What does it mean to shape light? Mark answers all these questions as he breaks downlight in easy-to-understand terms. Mark steps through the principles of light step by step. After explaining each principle of light, he applies it to specific modifiers.
The direction of light, contrast, form, shape, The Inverse Square Law, The Angle of Incidence and Reflection, soft light, hard light, Effective Size, color temperature, Dynamic Range, and more. Once you understand these principles you’ll understand the size, shape, and surfaces of each light modifier and how to use them most effectively. This class is jam-packed and perfect for every level of a studio photographer.

WHO THIS CLASS IS FOR:
Beginner to Intermediate portrait photographers
Portrait Photographers who work in the studio
Anyone looking to add more lighting gear to their toolbox
Photographers looking to expand their lighting options