Here, in pictures, is how. First of all, the finished painting, and a riveting thing it is. 

Next, the painting was photographed at such high resolution that you could see the very weave of the canvas. And from those files were generated proofs: the immaculately painted skin of Peter's model printed onto sections of vinyl billboard skin. Here they are laid out for scrutiny. An eyeful even at this stage.

With the proofs okayed by Peter, the majestic big printer at Adgraphix whirred into motion. Here you see Estelle, as Peter's favourite model is known, rolling through the HP Scitex XL1500's inner workings -- a scene worthy of the sci-fi classic Gattaca, which Peter has invoked more than a few times. The vinyl, which will be stretched in front of a bank of fluorescent tubes, is printed both sides so the colour stays rich even with light coming through it.

Finally, with Peter's painting now expanded from one metre to seven metres across, the team at Signtech moved in with their road cones and lifts. An hour or so later and there NDE was: an apparition hovering and staring above the city. We can't wait to hit the switch and see her glowing at dusk.