Since graduating from the Royal College of Art in London in 1986, John Forrester Clack has been exhibiting as a full-time artist. Based just outside Canberra, Clack is a maverick presence in the Australian art scene – his art practice is unusual, deeply personal, timeless and profoundly moving.

In this exhibition, a selection from seven years of his drawings, there is an overall consistency as well as uniqueness in each of the 20 pieces on display. Clack has the rare ability in his art to capture the moment of emergence of form: the moment of metamorphosis or transformation, when out of a mass of vigorous, energetic and explosive lines a form starts to emerge. The form is not fully graspable or completely defined, but appears like a head-shape loaded with fecund power.

In his drawings, Clack says just enough but not too much. The surfaces are heavily worked with a mass of lines and expressive gestural marks, leaving you to fill in the details in your imagination. The monumental heads appear to be caught in the act of awakening – frozen in a moment of creation. To viewers, they appear as revelations, emerging as if they have been willed into being.

Charcoal, graphite, oil and acrylic are employed on large sheets of primed and un-primed paper. These head and shoulder drawings are large, some 130 by 117 centimetres, and establish a sense of presence both through scale and through the sheer force of the mark. The paper frequently carries the scars of the process of creation, marking both the explosions of energy and the force with which the marks have been applied.

Clack is a spiritual and deeply theistic person – a true believer – where the process of making a drawing is part of a personal quest performed in a prayer-like state. He refers to many of these drawings as "Amen drawings", keeping in mind the Christian, Judaic and Islamic meaning of the word as: "so be it". In the final book of the Christian Bible (Revelations 3:14) Jesus is referred to as, "the Amen, the faithful and true witness, the beginning of God's creation". In one sense, Clack's "Amen drawings" represent a surrender to faith and to the moment of creation. The artist abandons self-doubt and the fear of failure and unites with a spiritual force to create within the moment with the medium and tools at hand. This breath of inspired creation is the strongest prevailing note throughout the exhibition.

John Forrester Clack is not a naïf artist, a person of faith working with an "innocent eye", but a highly trained and sophisticated artist who nevertheless manages to abandon himself to faith and process after many years of practice. While conscious of the gestural drawings and paintings of artists, including Alberto Giacometti internationally and David Fairbairn in Australia, he has pushed his art in a different direction. He has made truly inspired spiritual creations that appear to belong more in the realm of the celestial than the terrestrial.