In the 1950s, Tenreiro’s use of colour became gradually colder, and his compositions more sombre, with less light and more angular forms, anticipating what would be his black period. On returning to his hometown he was plunged into a depression that was reflected in his painting.

His introverted character drove him to search for the roots of everything around him—nature, colour, light, the atmosphere—and to reflect on his art and his own life as an individual. He pursued new signs of identity, a new visual vernacular that led him to break away from colour and to adopt black, leaving behind the smooth and uncomplicated landscape of before in order to look for the power of nature and the strength of stormy skies and seas.

He adopted black and earthy tones as the basis of his spectrum of colours. His brushwork thickened and expanded, becoming flatter and acquiring greater volume. The space of the canvas is now bathed in tragedy and drama, and the lack of characters gave way to the void. This was arguably the best period in his creation, when his work reached its greatest quality. From 1958 to 1964 his art moved within these parameters, particularly between 1960 and 1962. At the time, his paintings were unanimously praised by the critics. But soon he found himself in need of new challenges. He overcame his profound depression and longed for the colour which he had traded in for the implacable ethical stance he had imposed upon himself. He wanted to re-engage with light, which now flooded his interiors, his still lifes and even his portraits.

His subject matters—landscapes, seascapes, still lifes, interiors, beach scenes—contain a heightened sense of poetry as well as a highly personal way of looking at reality; a world of his own. His empty spaces speak of solitude, and his temperamental and highly personal skies are a signature element of his compositions.