When Deckard asks Rachael if Tyrell's owl is artificial, she replies 'Of course it is'. However, her lips movements do not match what we hear. This is because when the scene was filmed, actress Sean Young answered the question by saying 'Of course not'. Director Ridley Scott changed this in post-production because he wanted to establish that Tyrell could make perfect imitations of living things.
The film describes a future in which genetically manufactured beings called replicants are used for dangerous and degrading work in Earth's "off-world colonies." Built by the Tyrell Corporation to be 'more human than human', the Nexus-6 generation appear to be physically identical to humans — although they have superior strength and agility — while lacking comparable emotional responses and empathy.
The title derives from Alan E. Nourse's novel The Bladerunner (1974), whose protagonist smuggles black-market surgical instruments. William S. Burroughs' wrote Bladerunner, A Movie a cinema treatment. Aside from the title, neither Nourse's novel nor Burroughs's treatment are relevant to the film.
The Blade Runner owes much to Fritz Lang's 1927 film Metropolis. Scott credits Edward Hopper's painting Nighthawks and the proto-cyberpunk short story comic "The Long Tomorrow" (by Dan O'Bannon, art by Moebius) as stylistic mood sources. Scott hired Syd Mead as conceptual artist, both were influenced by the French science fiction comic magazine Métal Hurlant (Heavy Metal), to which Moebius contributed.
A high level of paranoia is present throughout the film with the visual manifestation of corporate power, omnipresent police, probing lights; and in the power over the individual represented particularly by genetic programming of the replicants. Control over the environment is seen on a large scale but also with how animals are created as mere commodities. This oppressive backdrop clarifies why many people are going to the off-world colonies, which clearly parallels the migration to the Americas. The popular 1980s prediction of America being economically surpassed by Japan is reflected in the domination of Japanese culture and advertising in LA 2019. The film also makes extensive use of eyes and manipulated images to call into question reality and our ability to perceive it.