Ash joined the Government School of Art, Calcutta in 1926, but had to leave for Madras after an open skirmish with the then principal, Mukul Dey, for Dey's pro-British stance. Ash joined the Government Art School in Madras as a student of the famous artist Debiprasad Roy Chowdhury.

Ash's art is celebratory. He was a member of the historical 'Calcutta Group' which was formed in 1943. Artist Prodosh Dasgupta was the founding member. Other top names who joined the group were Paritosh Sen, Gopal Ghosh, Nirod Majumder, Rathin Moitra, Shubho Tagore among others. Prodosh Dasgupta initiated and made Ash join the group in 1949.

The notion of modernism that prevailed during the late 40s and 50s was triggered by anxiety, fears, violence, mysticism and subversion. The conceptual transformation in these drawings, done in pen or brush and ink/pencil, is decisive.