The classical artists Rembrandt, Vermeer and Frans Hals made a lasting impression on Pietersen and had a strong influence in his masterful use of light. He studied several South African artists as well, WH Coetzer in particular, and spent many hours talking to local artists – possibly one of the greatest contributions to his work and style.
Pietersen is an extremely perceptive observer, and records a huge amount of detail in sketch books and slides during his many travels in the bush. These are then analysed to determine the characteristics of certain areas and sceneries. A painting is never an exact copy of a scene, but rather a collection of features to convey a specific impression. He might only start composing a painting depicting an area years later, using his sketches as reference material.
Pietersen prefers natural studies and landscapes in particular, although his still lifes consist of personal artefacts, often including his hat, pipe and books. The still life paintings usually reveal a definite focal point from where light is coming.
Apart from charcoal sketches of his sons, he never did portraits. His animal studies always depict the nature of the subject, and show a deep knowledge of animal anatomy where fine muscular and bone structure is emphasised.
Pietersen’s work has gone through different phases.
His earlier work included lush, green vegetation, and the animals were brightly coloured and sprightly.
His landscapes often depicted farms and the tranquil Free State grasslands.
When he moved back to the bushveld, the scenery became dryer and dustier and, apart from still lifes, showed little human connection.
When he moved back to the bushveld, the scenery became dryer and dustier and, apart from still lifes, showed little human connection.
During the mid eighties, the landscapes turned into barren and pessimistic scenes, and greys and morbid clouds were common.
This phase soon ended when a brain tumour was diagnosed and removed. He then started experimenting with textured canvas, night scenes where the moon in the painting gives an illusion of light in a room, and richly coloured sunsets. For a short period, very harsh shadows were incorporated in some works.
Of his more recent themes, are remarkable night scenes incorporating figures around a cooking fire, where viewers can marvel over his effective use of light. He is a master of depicting veld fires and camp fire scenes – themes that had been copied by other artists with limited success.
He has always had a great love for baobab trees, native to his home farm, and they are depicted strikingly beautiful in a variety of themes.
Pietersen is an inspired and disciplined artist. He gets up early – often before sunrise - and enjoys the company of a small campfire. As soon as the sunlight is the right intensity, he starts painting and, apart from refreshments, only stops in the afternoon when the sun turns yellow and the light is insufficient.
Viewers often ask whether a painting depicts a specific scene. Although it is never a photographic exposé of a specific sight, it is either a characteristic portrayal of a specific scene, or a ‘character study’ of an area. His work projects a remarkable realism and viewers familiar with an area, will recognise it immediately.