According to Deborah Caulfield Rybak, writing for Delta Sky Mag ("Screen Play: The World's Top Film Festivals," March 2012):
Each year, an estimated 5,000 festivals around the world -- some gargantuan, others as small as three films in a high school gymnasium -- screen films that might not otherwise find an audience.
They come from every place on the planet and from filmmakers both known and unknown. Some festivals are "industry" events, where studios and other distributors shop for smaller films to buy. Others are more audience-based, created to put new and interesting films in front of movie-loving audiences.
Rybak is talking about all film festivals, but the bulk of her article discusses indie films, which to most people mean non-genre.
I know of over 200 horror festivals worldwide (which Rybak doubtless includes in her estimated 5,000), but the festival opportunities for horror films are greater than 200. Many indie festivals welcome and award horror films. (Yes, they do -- despite some horror festivals' claims that the mainstream ignores horror. Not true.)
Rybak suggests that a festival's purpose determines when it screens. At least as far as the big players are concerned.
Conventional wisdom holds that distributors do their shopping at the major film festivals held at the beginning of the year. Later in the year, films considered to be potential winners on the Academy Awards/Golden Globes circuit are presented. Either way, a project's prospects -- financial and otherwise -- can be significantly altered by its festival appearances.
I'm not sure how much of this is true for horror film festivals. Although many mainstream festivals welcome horror, the Academy Awards and Golden Globes shun most genre films. This means that when a horror festival screens is irrelevant to that film's Oscar/Globe prospects.
Also be aware that many festivals, especially smaller ones, are one-time affairs. Despite which, the total number of festivals are increasing. Rybak says:
[T]he number of festivals continues to grow. There's a reason behind the explosion of film festivals, says Laurie Kirby, executive director of the International Film Festival Summit. The business of film festivals has become so big that Kirby's organization was formed to provide professional support and development to member organizations.
Yes, indeed. Film festivals are a growing business. Ever more people are shooting indie films (genre and mainstream), which means an ever more crowded field of films seeking distributors and audiences.
And ever more filmmakers willing to pay high entry fees for their shot at a festival screening.
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For a behind-the-scenes look at horror film festivals and the festival directors who manage them, see Horror Film Festivals and Awards. This book also includes a directory of over 200 horror film festivals, and a list of festival award winners from dozens of festivals over several decades.