Screenwriting vs. Novelling

I have written a post about the format of a screenplay, but how does writing a screenplay differ from writing a novel?  There are many differences, but here are some of the main ones I have noticed.

1. Screenplays focus on dialogue.  In a novel, dialogue is important, but action must be described very well to create a movie in the reader's head.  For example, if you are writing a book and are describing a black telephone, you might write a paragraph about write it tooks like.  In a movie, it will be there, on the screen.  

2.  In a screenplay, description is used as a guide for the directors to create the action with actors.  

3. A screenplay length is based on page numbers, not on word count.  In the world of novellests, word count is always talked about.  "My novel is 90k words!" or "I want my book to be at least 50,000 words."  In screenwriting, pages are the focus because when properly formatted, a page equals one minute of screen time.

I would like to take this time to thank my followers for putting up with the crazy posts here at Elvish Pens, Fantastical Writings!  Thank you!