The facts about the series are clear but few in number. In August 1974, Nixon was twenty-six years old, and had been married to Beverly (Bebe) for three years. He made a photograph of Bebe and her three sisters, Laurie, Heather, and Mimi, at a family gathering, but wasn’t pleased with the result and discarded the negative. In July 1975 he made another, and this one seemed promising enough to keep. At the time, the sisters were fifteen (Mimi), twenty-one (Laurie), twenty-three (Heather), and twenty-five (Bebe). The following June, Laurie Brown graduated from college, and Nick made another picture of the four sisters. It was after this second successful picture that the group agreed to gather annually for a portrait and settled on the series’ two constants: the sisters would always appear in the same order—from left to right, Heather, Mimi, Bebe, and Laurie—and they would jointly select a single image to represent a given year. (If you have sisters, or even if you don’t, you’ll know this course might be difficult; add to it the emotional dynamic of a husband/brother-in-law for whom artistic coherence and psychological presence are paramount, and you can begin to appreciate the challenge these simple constants present.) Also significant, and unchanging, is the fact that each portrait is made with an eight-by-ten-inch view camera on a tripod and is captured on a black-and-white-film negative. For a quarter of a century, Nixon printed these negatives exclusively as contact prints, so that the results were always the same size and showed exquisite detail and continuity of tone. Nixon has observed of his signature process, “It creates the illusion of being able to see more than the eye could see if you were there. It’s basically the clearest picture one can make in photography. Part of it has to do with faithfulness, but it’s also a matter of making a print whose quality of realism is so heightened that it’s sometimes surreal. Yet I can’t make it up: it’s absolutely there. I just love that. I’ve loved that for twenty years. I’ve tried everything from a half-frame camera to eleven by fourteen, but I stick to making contact prints. And eight by ten seems to be my size.” source : https://moma.org/explore/inside_out/2014/12/05/nicholas-nixon-40-years-of-the-brown-sisters/