A Look Behind the Curtain
When you watch Mary Poppins, you don’t usually ask, “How is Bert dancing with those animated penguins?” He just does—and the magic feels effortless. Behind that magic stood one of the most remarkable innovations in film history: the Disney sodium vapor process. Disney recently released a video celebrating the 55th anniversary of the Walt Disney Archives. The video highlights the prism that made the effect possible. For fans like me, the story feels fascinating and inspiring. It gives a clear “behind the curtain” glimpse into how Disney advanced film technology in the 1960s.
The Sodium Vapor Prism
The sodium vapor prism powered this breakthrough. Disney Legend Ub Iwerks—Walt’s close friend and creative partner since the earliest Mickey Mouse shorts—developed the process in the 1950s. Actors performed in front of a sodium vapor screen, and the prism let the camera separate them cleanly from the background. Unlike older methods, the process preserved soft edges, motion blur, and translucent objects. The results amazed audiences. Julie Andrews soared above London. Dick Van Dyke danced with animated penguins, and it looked natural and magical. This work on Mary Poppins (1964) earned the Academy Award for Best Visual Effects. Disney built only three prisms. One remains preserved at the Walt Disney Archives. This video presents a rare opportunity to view an artifact that revolutionized film history.
From Mary Poppins to Bedknobs and Broomsticks
The story did not end with Mary Poppins. Disney used the sodium vapor process again in Bedknobs and Broomsticks (1971). The technique blended live actors with magical animated worlds. For decades, it shaped how filmmakers handled composite imaging. Watching this history retold through the prism makes it even more meaningful. It shows more than technology—it shows Walt Disney’s constant drive to push storytelling forward.
A Story Worth Celebrating
This video, created for the 55th anniversary of the Walt Disney Archives, highlights the sodium vapor prism as one small part of Disney’s vast history. If such an amazing story can come from a single artifact, imagine what else the Archives hold. Disney’s past is marked by creativity and innovation. That is what excites me as a fan and why I started Sam’s Disney Diary. I want to celebrate not just the magic on screen but also the remarkable imagination and innovation that made it possible.
