Hologram

What is a hologram?

By Philip

A hologram is a physical structure that diffracts light into an image. The term ‘hologram’ can refer to both the encoded material and the resulting image.

A holographic image can be seen by looking into an illuminated holographic print or by shining a laser through a hologram and projecting the image onto a screen.

Other methods of projecting and reflecting images are often described as holographic – or even misleadingly holograms, because they have an optical presence, spatial quality or iridescent colors.

While it the past it there was a clear distinction technology is evolving to create virtual holograms by steering light into an image.   Augmented reality systems like the HoloLens often use a Holographic Optical Elements to make a video projection appear at comfortable viewing distance.  The virtual objects in augmented reality are a kind of ‘virtual hologram’

Kate Moss appears as a Pepper’s ghost video projection
Alexander McQueen A/W 06 show
via: GRAZIA

 & not a hologram –  The Pepper’s ghost technique, which uses a partially reflective surface to mix an image with the scene beyond.  John Henry Pepper demonstrated the technique in the 1860s with it being used to overlay visual elements (often a figure – ‘ghost’) onto a physical set or stage.