Frank Walter at Ingleby Gallery, Edinburgh

There’s no doubting the fertile imagination of Frank Walter, the Antiguan artist who died in 2009, aged 83. A self-taught painter as well as a portrait photographer, Walter’s vision encompassed the landscapes and people of his native land, painted in the vibrant colours of the Caribbean.

A recreation of the hut where Walter spent the last 25 years of his life gives an insight into this reclusive and highly eccentric visionary. Vividly coloured textiles cover a simple bed, while a camera and typewriter signal Walter’s obsessive, fecund creativity. A display case of black and white photographic portraits indicate, however, that his talents did not lie in this direction.

Photography did provide Walter with an unexpected asset. He used part of the box that was supplied with the Polaroid film as a canvas on which to paint hundreds of 10cm by 8.5cm oil studies, which indicated the economic poverty that he had endured.

Walter’s work came to the notice of the gallery’s proprietors through Barbara Paca, the American landscape architect who had known Walter for several years. The first commercial showing of his work was in Florida in 2011 and it is regrettable that Walter did not benefit greatly from his art in his own lifetime.

His compositions of trees, mountainside and sky show boldness and clarity, but it would be wrong to characterise Walter as a happy-go-lucky naïf. A large number of these works show the dark red and black of brooding hurricane skies, as if some version of pathetic fallacy were at work.

Walter visited Scotland in May 1960 (he was then living in the north of England). Some of the fruits of this sojourn are reflected in Scotland: Mountainside and River, and Scotland: White Water, White Sky and Cliffs, both completed decades after his visit here. They show a different, more muted palette. Compositionally they are effective, simple, unpeopled and without adornment. Like many of his Caribbean works, they inevitably reflect Walter’s sense of isolation.

Others works offer a different perspective, including the curious vision in Hitler Playing Cricket (with Antiguan Men). Perhaps the most sophisticated and perplexing is the trio The Photon, Complex of Life and Wavelengths (Light and Heat). Suddenly, Walter shuffles off his naïf cloak to reveal complex, mathematical, abstract sophistication.

Is Walter, after all, an exponent of what Jean Dubuffet labelled art brut, or something altogether more unfathomable?

The exhibition at the Ingleby Gallery runs until May 23.