In Morris Lum’s photographic archive of Chinatowns, change is the only constant. Wall murals are painted then covered up. Restaurant menus adapt to diners’ evolving palates. Colorful shopfronts fade and are replaced, as family businesses fall victim to rising rents or the disinterest of aging owners’ children and grandchildren. “That’s the life cycle of a Chinatown,” said Lum, who has spent more than a decade documenting commerce, community and architecture in Asian enclaves across the US and