I’ll wrap up this discussion with some miscellaneous lessons learned from the process of converting my stage play into a screenplay.
The spec script (which is the version created to sell the script) is a bit more of a literary document than the screenplay. In particular, the descriptions of the sets, then action, and the characters is expected to be a bit more colorful and complete than would be expected (or appropriate) in a stage play. People reading the screenplay expect to see the movie unfolding before their eyes. That same level of specificity is frowned on for stage plays because it limits the flexibility of the creative staff (Director, lighting, set design, etc.) I think this makes sense. There will be only one movie made (normally), but each production of a stage play is expected to be unique.
I ran into a bit of a problem figuring out how to handle transitions between scenes with the same characters where time has passed. Traditionally, a “Fade to black” could be used between the scenes to show the passage of time, but this gets a bit old and I wanted some different approaches to use. I ended up using one of three techniques in addition to Fade to Black. First, if I could include a different scene, with different characters, in between then that would solve the problem. (This is how I would typically handle this on stage.) On stage you do have the opportunity to show the passage of time by significantly changing the set, character ages, and so on, but typically only once as part the transition between acts. In movies you can do this more often, although I still felt like this type of transition has a bit of a jarring effect on the story flow, so I personally don’t like to do it too often. The third technique is pretty much specific to film. I found it worked well to focus in on one element of a scene (e.g., a candle on the table), then pull back to that same element but in a different scene (e.g., a candle on a alter). This approach seems to provide some continuity between the scenes, but to still allow a sense of passing time and different place.