David Hobby is an American photographer and author of the Strobist.com lighting blog, a site which promotes lighting techniques such as off-camera flash among photographic enthusiasts, often with an emphasis on the practical knowledge rather than the gear.
Strobist's 2019 X-Peditions workshops (Havana in January and Hanoi in the fall) have both filled.
Surprisingly, Hanoi actually filled before any public announcement. So if you think you might be interested in a future workshop, please make sure to sign up for advance notice on the X-Peditions info page.
If you would like to be placed on a wait list for either trip, you may do so at the individual workshop pages linked above.
Normally, you might think of a grid spot for what it creates: a tight zone of light. But it also can be helpful to think of it in terms of the inverse: a grid also prohibits light from reaching everywhere else.
And the "everywhere else" part—that relative blackness you can create with a gridded key—is what can help you to amp the color palette in even a small room with light-toned walls.