Hiding in plain sight (or rather in the internet underbrush) is a great national cinema: Mexico’s. Prospecting for its “golden age” can yield precious nuggets, somewhat tarnished by low resolution but watchable just the same.

Emilio Fernández’s “Salón México” (1949), Roberto Gavaldón’s “Macario” (1960) and Luis Buñuel’s “Illusion Travels by Streetcar” (1953) are three such movies, findable online with English subtitles. Examples of p opular — as well as populist — cinema, they were made in the post-World War II era when Mexico had become the world’s leading producer of Spanish-language motion pictures. Energized by savvy filmmaking and star performances and infused with folkloric elements, they were made as alternatives to, rather than imitations of, contemporary Hollywood movies.

Fernández, the most internationally celebrated of Mexican auteurs and the leading purveyor of Mexicanidad (Mexicanness), specialized in heroic tales of rural life — most famously the Cannes award-winner “Maria Candelaría.” His “Salón México” was a departure — a noirish musical melodrama set in a tawdry Mexico City cabaret to a near continuous rumba beat.

Mercedes (the Argentine actress Marga López) is a “fichera” (dancer, code for prostitute) who is determined to support her younger sister in a classy boarding school. Abused by her pimp, Mercedes receives moral support from a sympathetic cop (Miguel Inclán, the malevolent blind man in Buñuel’s “Los Olvidados”) who nevertheless proves helpless to avert the tragic ending.