This current show could well be his best yet. It features 24 paintings, all from the last six months of domestic isolation.

They continue the artist's passionate preoccupation with atmospheric landscape, with places seen or places sensed, in works with a newly robust structure and a heightened feeling for colour.

Almost all the paintings have a square format, which sets up a unique spatial challenge. Almost all are divided by a strongly defined horizontal which rises and falls like a wave around the walls. Sometimes this structuring device separates land and sea, sometimes land and cloud, but in many cases it represents the edge of a body of water which laps at our feet at the bottom of a painting, while in others we look across a body of water to the further bank right at the top.

Unusually for an artist who prizes universality, many of these paintings are specifically identified as sites on the Hawkesbury River, with its beetling cliffs and broad currents a new source of inspiration, rendered mysterious by swirling mists and gathering dusk.

Is there significance for the artist in the river's history, in its formal or more secret roles as colonial frontier? Apparently not. John Morris has never been interested in exact documentation in the manner in which Von Guérard and the other romantic painters of the 19th century came to terms with a new world, recently discovered by Europeans.

But like them, his paintings feed a hunger for an emotional immersion in the landscape, with a virtually palpable sense of awe. Exploring the Sublime in mountains, oceans or waterfalls readily becomes a mystical, even spiritual experience, the stuff of dreams. (An ocker anomaly in the exhibition is a strange impressionistic image of an emu scuttling into the tawny scrub, deliberately comic and clumsy.)

Other works also set up a contrast with the elegant and intense blue of the Hawkesbury paintings. A tempest gathers over the ocean. There is a regal, snow-encrusted mountain peak, obviously not Antipodean. There are scenes of bucolic farmland and a bushfire lapping at the ridge line above the paddocks.

In another small mysterious painting, the reflection in quiet water of a lighted window suggests an intuited human presence, a subject John Morris has returned to over many exhibitions. I vividly remember the road disappearing up a snow-patched hillside into the dark forest, a fountain splashing in a nocturnal garden and, more recently, the incongruous waters of a rooftop swimming pool.

Perhaps the new feeling for structure and the intensity of blue has superseded any human drama? Certainly, the range from inky midnight to translucent dawn in an electric turquoise is a visual challenge in itself.

It seems that John Morris has discovered a new urgency since forced to resign his teaching position in the restructuring of the Newcastle Art School in 2014. With unremitting energy, for 25 years he inspired generations of students to discover their individual voices. There was little time and energy for his own work, though he exhibited in group shows, as well as in regular solo exhibitions in Sydney and Newcastle, including in Anne von Bertouch's legendary gallery.

The Covid emergency has had its bright side, though it has meant no gallery visits. For art schools there have been the almost impossible challenges of teaching on line, with no face-to-face contact with students. But for artists it has often provided time in the studio to explore new ideas.

Interestingly, several artists have reported increased online sales during this time. John Morris has sold much of the present exhibition. A new painting can be an antidote to gloom.