Inglourious Basterds turns the films stored in the cinema into part of Shosanna and Marcel's plan. The flammability of nitrate has a historical basis; the sequence remains a dramatic construction.
Film stock enters the plot
Shosanna's cinema is not just the place where Nation's Pride is screened. It also contains prints and materials that belong to the everyday work of exhibiting films. The story draws attention to that physical medium in order to bring it into the attack plan. The film ceases to be merely a sequence of images and is presented as an object that is stored, transported and handled.
Cellulose nitrate stock was widely used during the early decades of cinema. Preservation institutions such as the George Eastman Museum explain its flammability and its tendency to deteriorate. That context makes it plausible that a collection of old films could represent a material risk. Not all celluloid films are nitrate, nor do all cinema stocks share the same properties.
The distinction between nitrate, acetate and other materials avoids a misleading generalisation. The word 'celluloid' is often used broadly, but the plot of Inglourious Basterds depends on a specific historical stock. It would not be right to transfer its behaviour automatically to any reel of film or any modern audiovisual archive.
The film explains that danger very emphatically because it needs the audience to grasp the narrative possibility quickly. The spectacular comparison it introduces should not be taken as a complete scientific account. A fictional film can rely on a real property and simplify its behaviour in order to build a clear sequence.
Shosanna and Marcel use what they know
The plan arises from Shosanna Dreyfus being in charge of the cinema. The decision to move the premiere there gives her an exceptional opportunity: to bring leading figures of the regime together in a space she knows well. She does not control Nazi politics, nor did she arrange from the outset for all the guests to arrive. She takes advantage of an event others have imposed on her professional life.
Marcel takes part in the preparation and in the execution. His role should not be reduced to that of a figure who obeys off screen while Shosanna does everything. The outcome depends on both of them acting in different spaces and on certain actions being able to continue even while she is trapped in the projection booth. Their cooperation allows the plan to exist more broadly than in the physical presence of its author.
Sealing off the exits has a precise narrative function: it turns a place of exhibition into a space from which the audience cannot leave freely. To analyse the scene, there is no need to describe procedures or give instructions about fires. What matters is the reversal of spatial power. Those who have occupied the cinema as privileged guests lose control over their movement within it.
The screening of Nation's Pride is also part of that organisation of time. The audience is gathered and attentive to a performance staged to celebrate the regime. Shosanna's message interrupts that framework through the very device that sustained it. The material threat and the intervention on the screen meet in a single event.
Plausibility does not amount to documentary reconstruction
The sequence combines fire, gunfire and explosions coming from different plans. The visible result cannot be attributed solely to the nitrate as if this were an isolated demonstration. Editing brings causes and effects together to reach an alternate-history ending. The scale, speed and dramatic coordination of the destruction belong to that cinematic construction.
The historical risk of nitrate also does not mean that all cinemas of the period operated without protective measures. The preservation and screening of the material require specific conditions, and its history includes attempts to control that danger. Fiction selects the vulnerability that serves its plot. It does not, on its own, summarise the full professional practice of cinemas of the period.
The image of films burning adds a paradox. The cinema gives Shosanna a job and a way of life under a protected identity, but it can also be turned into an instrument of her response. The archive stops preserving images and takes part in destruction. That reading comes from the object's function within the story, without needing to attribute to the director a statement about the burning of real archives.
It is also worth separating the fictional fire from its audiovisual realisation. The sound, lighting, effects and editing create an experience that is not the same as observing a fire without mediation. The sound of celluloid burning belongs to that construction, while information about filming the set requires specific testimony and cannot be inferred from the intensity of the scene.
Within the ending of Inglourious Basterds, nitrate connects craft, memory and action. Its presence allows the owner to respond from the material world she knows. The historical basis explains why the device is recognisable; the staging carries it towards a revenge fantasy that deliberately alters the history of the war.
More context in the Inglourious Basterds guide.