David Singer's first poster began a dramatic transformation of the concert poster. Singer's style was precise and carefully planned, in contrast to the free-form, more spontaneous work of previous artists. Singer also changed lettering styles because, "... by then the shock value... of posters being illegible had worn off." His lettering was more linear, but that did not mean he took the psychedelic out of psychedelic posters. He simply achieved the effect in different ways.
During his Fillmore era, from 1969-1971, Singer created more posters for Graham than any other artist. Singer's posters are notable for his use of collage, incorporating thousands of images clipped from magazines spanning several decades. He developed a format that included a stunning variety of lettering styles, applying them in close relation to the theme or subject of a poster.