Remember the almost otherworldly glow of Space Ace's laser? Or the way sunlight streamed through a window in AKIRA, making the very air feel thick with light? These aren't just happy accidents; they're often the result of a clever, albeit somewhat forgotten, animation technique called underlighting, also known as "Bipack Glow."
Before the digital age swept through animation studios, creating a convincing glow was a painstaking process. Animators would have to meticulously draw each luminous fringe, a task that, even when done perfectly, often lacked that truly ethereal quality. The solution? A bit of old-school ingenuity. Imagine cutting a precisely shaped hole in the animation background, then shining a bright light up from beneath. The effect was, as the reference material puts it, "rather awesome-looking," with natural-looking tapering fringes that mimicked real-world light.
It wasn't without its challenges, though. This technique was labor-intensive because the hole in the background had to move frame by frame to keep pace with any glowing object. This often meant underlighting was reserved for static elements or smaller moving objects to keep the workload manageable. Adding texture was another hurdle; while translucent foils or even a mix of soap, water, and glitter in a glass tube could be used, it made the technique best suited for amorphous effects like energy beams or lightning rather than detailed characters.
As digital tools became more accessible in the late 1990s and early 2000s, underlighting began to fade. Computer programs offered animators far greater flexibility and control over glow effects, allowing for intricate textures and dynamic movement that were previously impossible with traditional cel animation. The rise of CGI in live-action filmmaking also rendered underlighting obsolete for similar reasons, offering even more seamless integration with live footage.
Yet, there's a curious irony. While digital tools can replicate many effects, achieving the exact, nuanced glow of underlighting in hand-drawn animation remains incredibly difficult. The complexity of real-world light, especially how it refracts and creates those subtle tapering fringes, requires a massive amount of frame-by-frame effort to replicate digitally. This has led to underlighting becoming something of a "Forgotten Trope" in many circles.
Still, its legacy lives on in some truly memorable moments. Think of the sunlight through the window in AKIRA, or the subtle glow of coals in a pipe in The Great Mouse Detective. Even modern films like The Boy and the Heron have intentionally simulated underlighting as a retro effect, using advanced HDR technology to capture that distinct visual feel. And who could forget the iconic proton pack streams in Ghostbusters or the glowing eyes of Nicodemus in The Secret of NIMH? These are all testaments to the enduring power of this once-revolutionary technique, a reminder that sometimes, the most magical effects come from looking at light from a different angle.
