COLOURED shadow puppets are not new to this part of the world, for they originated in China. Today, the old technique of projecting coloured puppet shadows on to a screen has been put to good effect by the Underground Railway Theatre from the United States. Answering questions after the show, the company's co-director, Wes Sanders, explained that where Chinese puppets were cut out of animal skin and coloured with dyes, the ones he and his colleagues use were made of clear plastic which is painted with the same materials that film animators use. The evening's programme was made up of a version of Till Eulenspiegel's Merry Pranks, to the accompaniment of a tone poem by Richard Strauss, and The Firebird, set to music by Igor Stravinsky. The first of these related the escapades of an incorrigible rascal, Till Eulenspiegel. The German folk hero gets up to all sorts of trick and jokes. In an anarchic manner, he devotes his efforts to giving unscrupulous or pompous people their comeuppance. In one incident, for instance, he steals the bulging purse of a greedy monk who has been selling haloes to naive villagers, when all they wanted was forgiveness for their sins; then, he returns the money to the villagers. On another occasion, by asking a couple of learned men some important questions, Till shows them up for what they are - mere windbags. The Russian tale of The Firebird also contains drama and excitement. A wizard has taken the sun's power to use for his own destructive purposes. Hunting in the wizard's garden, Ivan shoots the Firebird with an arrow. Remorsefully, Ivan swears never again to kill a living thing, whereupon, the bird's spirit gives him a wing feather which has magical properties. The great power of the feather, however, is just what the wizard wants, in order to rule the world. In the event, the feather helps Ivan to overcome the wizard, and to rescue his victims who have been frozen in an ice palace. Technically, the skill of the puppeteers was impressive, particularly the use of the flexible mirror puppet which reflected ever-changing shapes of light on to the screen to represent the spirit of the Firebird. Theatrically, though, there were sections that palled because what was happening visually occasionally had to wait for the music. The ice palace sequence in The Firebird was particularly laboured in this respect. Another problem was the narrator's microphone technique. Although the sound equipment itself seemed in order, it was very difficult to catch all the words, even sitting in the fifth row. Till Eulenspiegel and the Firebird, Underground Railway Theatre, Studio Theatre, Cultural Centre. July 29-31.