Rereading Moving Pictures, today it occurred to me that there is a strong alchemy base to the story. I don't mean the obvious one, that the alchemists invented - or were caused to invent - octocellulose which let them invent moving pictures. I mean the symbolism of alchemy, as it was used in the Renaissance to symbolize a human process of personal growth. It's not a one-to-one correspondence, but there seems to be a connection.
The deliberate mystification of alchemy symbolism had variations, but there were certain things that stayed fairly consistent. The material to begin with was common, worthless, and found everywhere.
The standard formula for alchemy is a combination of sulphur (yellowish), mercury (quick-silver, "living silver"), and salt (often considered unnecessary but the third element was traditional). In Holy Wood there is a screen that looks like mercury, and the screen in Ankh-Morpork becomes the same when it is taken over; when the Things from the Dungeon Dimensions break through, they take on the appearance of being coated with mercury even though the films were made in color. In Ankh-Morpork and again in Holy Wood, the TFTDD break through a mercury-like screen. The fireball that destroys the gate in Ankh-Morpork is lit with matches, which are still made with sulphur.
There was a sequence of color coding in alchemy: the process began with black putrescence, moved to white light and dawn, then on to yellow or golden light, and then to red, the Rubeus stage at which the Philosopher's Stone could be used for life extension or to turn base materials into gold.
Victor (and Ginger) go through the intensely dark tunnel to the rotting theater under the hill, where Ginger (entranced) holds up a torch that produces blindingly white light. The theater mechanisms have broken so they leave, getting caught in the blackness of the tunnel again until rescued by the dogs and the trolls. (The professional dog, Laddie, is golden yellow.) The tunnel collapses and the next morning there is a shining white fog.
People asked Sir Terry whether the coincidence of Ruby's and Ginger's names both meaning "red" were an allusion to Scarlett O'Hara. He said no. But nobody asked him whether they were alchemical, referring to the Rubeus stage. Ruby comes out of the darkness of the jazz club and makes an impression on Detritus (detritus means "a common material, considered worthless"), who immediately begins to reform his old way of life. Ginger manages to energize even Victor to attempt more than he had intended before.
