One of the most reliable rewards of folk art is its honesty: the straightforward methods and materials of its making, and the directness of its purpose. The small devotional paintings known as retablos are especially poignant for their frank demonstrations of faith. Produced by the thousands by anonymous 19th-century Mexican artists, these images of Jesus, the Virgin Mary, and countless saints were placed in home altars and left at pilgrimage sites. Today they intrigue particularly for their curious blend of native and European cultures. At Paul Thiebaud Gallery, a selection of nearly 200 of these paintings reflects the astonishingly varied production of a cottage industry that thrived between 1820 and 1920.

The conquering Spaniards brought to Latin America a tradition of votive images painted on wood and canvas. Such objects remained out of the economic reach of most Mexicans, however, until tin became available as an inexpensive support in the 19th century. The retablos were not considered fine art, but rather devotional objects, their designs borrowed from prints, sculptures, and other paintings, and mass-produced by artists of varying talent but usually no academic training. Their dimensions were determined by the standard sizes of the tin sheets, which were frequently cut into halves or quarters.

The paintings at Paul Thiebaud, mostly dated simply as “nineteenth-century” pieces, are grouped by themes and saints. This arrangement highlights the works’ dizzying range of technical and aesthetic prowess, which ranges from the crude to the highly polished, all filtered through second- and third-hand experience of European models. One senses echoes of, variously, the elegant reserve of Veneziano, the dark vigor of Ribera, the softened, umber tones of Murillo, and the limpid, planar blues and pinks of Tiepolo. Such influences — among many others — are often heightened in sentiment with festive floral decorations and bloody details.

In some cases, the original models are known. An especially graceful “El Alma de Maria” (“Virgin of the Dove,” to English speakers) is one of many based on a painting by the Mexican artist Manuel Caro (1761-1820) — or rather, a print of his original, as the image is reversed. Three retablos titled “La Madre Santisima de la Luz” (“Our Lady of the Light” — protector from plagues and natural disasters, and patron saint of electricians) all derive from a single large Italian painting shipped to the Cathedral of León in central Mexico in 1732. Though they range from the warmly naturalistic to the daintily ethereal, all three adhere to a complex design that has the Virgin Mary lofting a sinner with one hand, while clasping the Infant Jesus in the other; the Infant nimbly plucks one burning heart from a basketful offered by an angel.

Many iconographic details survived the transatlantic voyage intact. Saint Isidore the Laborer, patron saint of farmers, still wears the knee-britches of his native Castile. The elements of many of these retablos, though, would only be at home in the New World. Several present the Virgin of Guadalupe, symbol of the Mexican nation since its independence, surrounded by a golden mandorla and garlands of roses. (According to legend, the Virgin appeared to San Juan Diego on a hill near Mexico City.) Two paintings titled “La Virgen del Pueblito” turn Mary’s garments into a broad pyramid suggestive of the mountain goddess worshipped in pre-colonial times. Another painting portrays San Benito de Palermo, a Sicilian descendant of African slaves and patron saint to black peasants, holding aloft a crucifix and flaming heart.

Three retablos of San Camillo de Lellis (patron saint of doctors, nurses, and gamblers) neatly demonstrate the independent initiative of some artists. While all present the saint tending to a patient amidst cavorting demons, the motifs shared by two of them — a skeleton, a grilled window — are absent in the third, which includes, weirdly enough, the Masonic symbol of an eye in a hovering triangle.

Many of the retablos delight in the turgid particulars of Christian iconography. The morbidity can be subtle, as in the placid image of San Ramon Nonato, the patron saint of midwives and pregnant woman, whose mouth is sealed with a padlock. More bizarre is “La Mano Poderosa” (“The Powerful Hand”), depicting the blood from a large hand’s stigmata streaming into the mouths of seven lambs. Three images of the flagellation of Christ are truly gruesome in their detail. By contrast, several paintings titled “The Trinidad” are the very picture of transcendent calm, with Father, Son, and Holy Ghost staring with identical, impassive expressions from a vantage point of clouds and angels.

In the early 20th century, the advent of cheap color printing spelled an end to the retablos, although not to a subcategory of ex votos that were dedicated to saints for their intercession in personal afflictions. With their scenes of specific calamities, accompanied by handwritten descriptions, these paintings speak of hopes and sufferings with particular intimacy. One of the several ex votos at Paul Thiebaud pictures a farmer accidentally shooting his own hand, while another, dated 1940, features a bloodied pedestrian under a car. In both cases, the artists’ straightforward and naïve renderings feel completely in accord with the ardent needs of the victims and their families. From our cultural distance, the images are especially touching. It’s easy to patronize these depictions of pain and faith for their charm, but we may hope to find nourishment in them, too.

Until August 2 (42 E. 76th St., between Park and Madison avenues, 212-737-9759).