Despite instability ushered in by Martial Law in 1972, the museum continued to be relevant in the 1970s. Its founder went into self-imposed exile in San Francisco, California, passing away there in 1975. His eldest son Eugenio Jr., jailed by President Ferdinand Marcos, managed to escape five years later in 1977 to the United States. Until the Marcos regime was toppled in 1986, Oscar M. Lopez, the next oldest sibling, was left in charge of all Lopez companies and assets. He started to actively head the foundation in 1973. Journalist Celso Cabrera served as Museum Director from 1972 until 1979.
As the decade closed, the museum prepared to publish several titles. Santiago A. Pilar, well on his career as a professor of Philippine colonial art history, wrote Juan Luna: The Filipino as Painter. Released in 1980, it was the museum’s first art book and the first full-length biography on the controversial artist. The Lopez Family book that appeared in 1982 stimulated interest in family genealogy. As a gesture of its high regard and appreciation, the board dedicated Philippine Rariora: A Descriptive Catalogue of 17th Century Imprints in the Lopez Memorial Museum to its author, the foremost Filipino bibliographer Mauro Garcia who died before its launch in 1983 (p. 168).
The museum quietly expanded its endeavors in the natural sciences. Manolo M. Lopez, Oscar’s younger brother, would serve the Philippine Orchid Society as president. The museum gave the University of the Philippines a grant to create an orchid gene bank when it set up its own nurseries to upgrade native varieties and enhance their world appreciation. Those projects set the stage for The Complete Writings of Dr. Eduardo Quisumbing (published in 1981) and the salute to Philippine endemic orchids by Helen I. Valmayor, Orchidiana Philippiniana (released in 1984).
Although it had halted acquisitions, the museum purchased the library of The Manila Times that was forcibly closed during martial law. The Times library possessed the most complete collection of the newspaper starting from the American colonial period onwards and is one of the biggest additions to the printed collection. By then the annual monsoon flooding in the Lancaster street area was rising and identified as a major threat to the collection. The distance from schools and flooding eventually saw the entire collection packed and moved to safer grounds on 1985.