Ola Billgren's painting, ‘Portrait Study, Hanna D.’, brings together two important parts of his oeuvre: the photorealism of the 1960s and the fascination with the colour red that was so strong in the 1990s. Splashes of red began to appear in Billgren's paintings in the latter half of the 1980s, for example in ‘Historia’, 1986, and ‘Trettio år i Lund’, 1989, and later his interest in the colour scarlet gained momentum and he painted a whole series of red motifs. Billgren believed that the red pigment had a versatility that other colours often lacked, it could express both life and warmth but also aggressiveness. In the red paintings Billgren used photography in a new way. The photographic image was used as a model, first carefully painted with a brush, red in red, and then the motif was scraped off with a metal rake. The technique recalls the protracted nature of the photographic process, and the result is contradictory: the photographic image does not communicate directly to the viewer, but exists in the distance on the edge of visibility. Behind the veils of colour left by the scraper, one often glimpses a subject with intimate or romantic overtones, an interior, a garden, a café, or as in the painting in the catalogue - a human form. With his special colour treatment, Billgren has created paintings that touch us on all levels.

In the winter of 2010/2011, a number of Billgren's paintings from this period were exhibited at Bror Hjorths Hus in Uppsala, where the museum director shared his thoughts on Billgren's red masterpieces:
‘- Red strikes a chord with all of us,’ says Tomas Järliden, museum director at Bror Hjorths Hus. No other colour is so associated with our emotions as red. ‘I saw red’ we say when we get really angry and life appears “rosy” when we fall in love. Red also alludes to festivals and holidays. Celebrities walk the ‘red carpet’ and holidays are marked with red in the calendar. But red is also the colour of pain, guilt and shyness. Ola Billgren's red painting cannot be divided into any single category. It spans the entire emotional spectrum and individual scale of interpretation of the colour red.’