'On the impetus of ideas simmering within him for his own approach to landscape he went to Emu Plains, and there produced these most astonishing morning light subjects ... It must have been with a queer exultation of inspired emotion that Gruner, wrapped in chaff-bags to keep the chill out of his blood, watched for those clear colourless dawns to arrive, with a palette set to a key that would paint the unpaintable, light itself.'
- Norman Lindsay, 1918
Often regarded as 'the last of the Australian impressionists', Gruner established his reputation during this period, as perhaps the country's most accomplished and lyrical painter of light and certainly its most dedicated plein-airist, always painting out-of-doors in front of the motif. His early work revealed a nostalgic admiration for the traditions established by Arthur Streeton and the artists of the Heidelberg school, but early in his career, Gruner became inspired by influential Melbourne-based artist and theorist Max Meldrum who propounded tone as the most important component of painting. He began to experiment with his techniques and most importantly, favouring the intense clarity of winter dawn, turned to paint into the light, so that his forms became dark silhouettes lit from behind. His landscapes entered a new spiritual realm that transcended the simple pastoral scenes depicted and marked his emergence as the new 'apostle' of light. At the same time, the broken colour of the foreground of this work suggests Gruner's interest in the paintings of Emanuel Phillips Fox, which he would have exhibited in Sydney in 1913.
Widely celebrated at the time of its Wynne Prize award in 1919, 'Spring frost' remains Gruner's most popular and well known work. Although painted largely out-of-doors at Emu Plains, its large size and somewhat theatrical quality make it likely that Gruner completed parts of it later, in the studio.