In the 1990s, Thomas Kinkade was the most successful artist of his time. His sentimental, sanitized landscapes full of Christian motifs and storybook cottages, some of which were lit with tiny LEDs embedded in the canvas, were so popular that, at one point, it was estimated that one in 20 American houses owned Kinkade artwork via a painting, a calendar, a Christmas ornament, a postcard, a commemorative plate or a LA-z-boy recliner dressed in his fabric.

Kinkade, who died of an overdose of alcohol and valium in 2012, called himself the “Painter of Light.” His trademark art consisted of romanticized environments complete with golden sunsets, an abundance of pastels, and cozy homes that glowed excessively from within. While the masses loved him, the art world despised Kinkade.

In the recently released documentary “Art For Everybody,” director Miranda Yousef reveals that before Kinkade built a multimillion-dollar empire, thanks in part to professing himself...