Giovanni was born in Turin; he first studied engineering but gravitated to painting without a formal education.
[1] He was an older brother of Eugenio Colmo, known as Golia, a noted cartoonist, caricaturist and watercolorist.
This latter group painted outdoors on scene, and were interested in capturing seasons, times, and weather.
Among his colleagues in painting mainly the Piedmontese alpine valleys were Anselmo Sacerdote, Vittorio Cavalleri and Carlo Pollonera.
This article about an Italian painter born in the 19th century is a stub.