<P> An important innovation in special - effects photography was the development of the optical printer . Essentially, an optical printer is a projector aiming into a camera lens, and it was developed to make copies of films for distribution . Until Linwood G. Dunn refined the design and use of the optical printer, effects shots were accomplished as in - camera effects . Dunn demonstrating that it could be used to combine images in novel ways and create new illusions . One early showcase for Dunn was Orson Welles' Citizen Kane, where such locations as Xanadu (and some of Gregg Toland's famous' deep focus' shots) were essentially created by Dunn's optical printer . </P> <P> The development of color photography required greater refinement of effects techniques . Color enabled the development of such travelling matte techniques as bluescreen and the sodium vapour process . Many films became landmarks in special - effects accomplishments: Forbidden Planet used matte paintings, animation, and miniature work to create spectacular alien environments . In The Ten Commandments, Paramount's John P. Fulton, A.S.C., multiplied the crowds of extras in the Exodus scenes with careful compositing, depicted the massive constructions of Rameses with models, and split the Red Sea in a still - impressive combination of travelling mattes and water tanks . Ray Harryhausen extended the art of stop - motion animation with his special techniques of compositing to create spectacular fantasy adventures such as Jason and the Argonauts (whose climax, a sword battle with seven animated skeletons, is considered a landmark in special effects). </P> <P> Through the 1950s and 1960s numerous new special effects were developed which would dramatically increase the level of realism achievable in science fiction films . </P> <P> If one film could be said to have established a new high - bench mark for special effects, it would be 1968's 2001: A Space Odyssey, directed by Stanley Kubrick, who assembled his own effects team (Douglas Trumbull, Tom Howard, Con Pederson and Wally Veevers) rather than use an in - house effects unit . In this film, the spaceship miniatures were highly detailed and carefully photographed for a realistic depth of field . The shots of spaceships were combined through hand - drawn rotoscoping and careful motion - control work, ensuring that the elements were precisely combined in the camera--a surprising throwback to the silent era, but with spectacular results . Backgrounds of the African vistas in the "Dawn of Man" sequence were combined with soundstage photography via the then - new front projection technique . Scenes set in zero - gravity environments were staged with hidden wires, mirror shots, and large - scale rotating sets . The finale, a voyage through hallucinogenic scenery, was created by Douglas Trumbull using a new technique termed slit - scan . </P>

Describe the various technology used to give special effects in the movie bahubali 2