Clever Techniques for Filmmaking: Synthesizing the Sky

Film Shoots Rely on Weather

One of the most concerning factors during film shoots is the weather. Unlike Hollywood’s rain-scarce climate, Japan experiences frequent rain, often forcing delays or cancellations.

When we broadly categorize weather as sunny, cloudy, or rainy (including snow), you’d be lucky to film under sunny conditions once every three shooting days. The sky in live-action films is, quite literally, left to chance.

For instance, if your script calls for a sunny day but you end up with overcast skies, what would you do?

Would you, like Akira Kurosawa, wait for “the ideal weather”?

Kurosawa’s dedication to perfection is legendary, and many hail his anecdotes as emblematic of the ultimate creative spirit. I adore his stories and even own several books detailing them.

But let’s be realistic—Kurosawa’s pursuit of perfection is an “ultimate bonus.” It’s akin to someone building a luxury mansion and obsessing over the exact sheen of the curtains.

For most of us, though, we’re still at the stage of ensuring our “houses” have straight pillars, level floors, and no leaks—all while meeting deadlines.

Attempting to mimic Kurosawa’s “wait-for-the-weather” approach often leads to enormous delays, trade-offs in other areas, and ultimately, incomplete projects.

Perfect Outdoor Weather is Rare

If the weather isn’t ideal on the day of your shoot, make the best of it and proceed. The reality is that ideal filming conditions are exceptionally rare.

Even in television dramas, some productions are blessed with good weather, while others are not. There was a series set on the Shonan Coast where nearly every outdoor scene featured overcast skies. It must’ve been disappointing for both the crew and cast.

Even with the same script, the impression of outdoor scenes can vary significantly depending on the weather. Furthermore, achieving consistent lighting in outdoor shots is surprisingly challenging because weather, cloud positions, and the passage of time cause dramatic shifts. Often, such issues aren’t noticed until the editing phase.

At one point, I focused on indoor or nighttime scenes to avoid the challenges posed by sunlight and weather changes. These settings allowed me to shoot more efficiently.

The Advantages of Synthesizing Skies

Does this mean independent filmmakers must abandon the joys of pursuing “that little extra”? Not necessarily! I recommend compromising on perfection during filming and focusing instead on adding that extra charm during the editing stage.

For example, take the sky.

In animated films, painted skies often serve as striking backdrops. Director Mamoru Hosoda has discussed in interviews how he uses “summer blue skies and cumulus clouds” to symbolize youthful growth in his works. The vivid backgrounds he employs create a palpable sense of exhilaration.

Why not experiment with compositing “blue skies and cumulus clouds” into long shots of your outdoor scenes? With meticulous editing, you can craft natural-looking landscapes.

Even in outdoor scenes, unless you’re shooting a sprawling meadow, the sky likely occupies a minimal portion of the frame. By compositing vibrant skies into the most prominent sky shots, you can transform the scene’s overall impression.

I’ve previously composited sunsets and even used sky replacement techniques to seamlessly blend shots filmed under different weather conditions:

• Character A against clear skies.
• Character B against overcast skies.

When alternated, such scenes create jarring inconsistencies. To solve this, I added clouds to Character A’s clear sky and a “peeking blue sky” to Character B’s overcast background. While the light conditions technically differed, the illusion successfully reduced viewer discomfort.

With careful effort, computer-based compositing can entirely conceal the fact that the footage was altered.

Embracing Artistic Creativity

Critics dismissing such visuals as “fake” are misguided. After all, filmmaking is, by its very nature, an exercise in crafting illusions.

By incorporating compositing into your skill set, you add a painterly dimension to filmmaking, enriching the creative process.

I hope you find this helpful—thank you for reading!