ɪn nˈaɪntiːnhˈʌndɹɪd sˈɪksti θɹˈiː, nˈoʊltən dɪvˈɛləpt ðə bᵻflˈɪks bˈɛl flˈɪks pɹˈoʊɡɹæmɪŋ lˈæŋɡwɪdʒ fɔːɹ bˈɪtmæp kəmpjˈuːɾɚpɹədˈuːst mˈuːvɪz, kɹiːˈeɪɾᵻd jˈuːzɪŋ ɐn ˌaɪbˌiːˈɛm sˈɛvən θˈaʊzənd nˈaɪnti fˈoːɹ kəmpjˈuːɾɚ ænd ɐ stɹˈɑːmɜːɡkˈɑːɹlsən fˈoːɹ θˈaʊzənd twˈɛnti mˈaɪkɹoʊfˌɪlm ɹᵻkˈoːɹdɚ.
In 1963, Knowlton developed the BEFLIX (Bell Flicks) programming language for bitmap computer-produced movies, created using an IBM 7094 computer and a Stromberg-Carlson 4020 microfilm recorder.