ɪn nˈaɪntiːnhˈʌndɹɪd sˈɪksti sˈɪks, nˈoʊltən ænd lˈiːɑːn hˈɑːɹmən wɜːɹ ɛkspˈɛɹɪməntɪŋ wɪð fˌoʊɾoʊməsˈeɪɪks, kɹiːˈeɪɾɪŋ lˈɑːɹdʒ pɹˈɪnts fɹʌm kəlˈɛkʃənz ʌv smˈɔːl sˈɪmbəlz ɔːɹ ˈɪmɪdʒᵻz.
In 1966, Knowlton and Leon Harmon were experimenting with photomosaics, creating large prints from collections of small symbols or images.