The stage exerts a magical attraction; it is a place that frees the imagination, a place where time and space seem unbounded despite the physical confines of the stage and the temporal confines of a performance. The stage is a place for semblance; everything is semblance, which is precisely what invests stage design with so much potential, above all for a Wagner opera, and most especially Tristan, as we envisioned it in our conversations with Stefan Bachmann. Wagner's music and the performers’ voices are so exceptional that stage sets and staging could easily become an unwelcome distraction. We therefore wanted to generate pictures that are neither illustrative nor restricted to one single interpretation. The stage sets and the staging would not represent the things themselves but rather their appearances. In other words, not simply emergence and disappearance but rather the appearance of emergence and the appearance of disappearance. The appearance of the hull of a ship, stairs, a cave or part of a body, a concrete form and identity, and the appearance of emptiness, of nothing, of a zero space.
We did not want to use conventional technologies like video or slide projections in order to make things emerge, to magically whisk them onto the stage. Instead we wanted to generate a tangible experience that would have a much more direct, physical impact on the spectators. This would also enable the singers actively to engage with the onstage image instead of merely standing next to projected images. The technical implementation of our ideas proved to be rather difficult and would have failed if it hadn't been for the extraordinary commitment of the stage technicians and our assistant Claudius Frühauf, who had already spent months in Basel devising models and methods that would be able to produce the desired images. When we first tested the model and later conducted full-scale tests on the stage, we found that what we had envisioned had indeed come true. Using negative pressure in a specially designed pressure chamber, it was possible to mould and shape a rubber membrane to create appearances that were constantly changing, breathing, imperceptibly overlapping, fading in and fading out. With the addition of precision lighting, these appearances acquired an almost hallucinatory effect.
Herzog & de Meuron, 2006