The “Tracing the Conical Cup?” exhibition is all about picking apart the many ways that TPW answers questions about these simple little pots, and then translating those questions into a visual representation which museum visitors can enjoy. But we regularly take for granted one of the simplest questions about these cups: What were they used for?

When you explore our exhibition, and as you make your way through many other museum spaces, cups and jars, cooking pots and platters are shown on pedestals and protected from dust and dirt. We wanted to find a way to bring life back to these everyday objects, and I thought it was a great opportunity to bring in a visualisation technique which is not necessarily new, but still feels fresh and futuristic. Our conical cup holobox is an old technology disguised as innovative new technology, with the added element of a conical cup replica physically taking centre stage. The holobox allows us to show the tangible object with a ghost of its probable use life – plentiful liquid pouring down.

How is this display achieved? The technique I had in mind to realise this is actually a ‘false’ hologram, because actual holograms do not have the photorealistic colours and require specialised equipment and processes. To create this display I used basic optics to give the illusion of a sense of presence in a space: the ‘Pepper’s ghost’ technique, an old technology disguised as innovative new technology. The simplest form is to project an (moving) image onto a transparent surface, like glass or very fine fabric. The image then appears to float through space. Modern technology makes it possible to project 2D recordings real-time in existing situations by positioning a glass or plexiglass plate obliquely in the room. A screen lying horizontally on the floor or ceiling then reflects the image onto the diagonal plate, giving the illusion that the image is standing upright and interacting with the surroundings.

Many people are already familiar with this technique, albeit probably on a subliminal level: most Dutch people have probably experienced the technique in the ‘Spookhuis’ (haunted castle) of the theme park Efteling, where you can see a floating violin and scary ghosts behind windows. Others may have come across it when watching the episode ‘The Abominable Bride’ in the BBC drama Sherlock or read about ‘live’ concerts of deceased artists such as Tupac or Amy Winehouse performing as holograms.

This is the technique I applied in the ‘holobox’ on display in the exhibition. The liquid pouring into our conical cup is a simple looping video, played on a tablet in the compartment of the box above. The plexiglass sheet is placed at an angle with the actual cup behind it and thus, a plain little cup becomes a vessel to bring visitors closer to the question “what were the cups used for?”

Are you interested in learning more about the Pepper’s Ghost technique? Build your own holographic projector with just your smartphone and a piece of plexiglass (or even an old cd-case!) by following the guide in the video below…

We have put together a small video to match the exhibition theme, so use this to try out your own holobox: