Astrid Preston’s paintings depict landscapes both mundane...

SAN DIEGO —  Astrid Preston’s paintings depict landscapes both mundane and extraordinary and are strongest when these two realms merge in a single shared space.

In her show at Patty Aande Gallery (660 9th Ave.), the work itself ranges from mundane to extraordinary. A dozen 5-by-7-inch paintings spanning one wall are as small in concept as in size. Like snapshots from a travel album, these blandly rendered views of lakes, hills and skies feel remote and uninvolving. But when Preston introduces architecture into her compositions, or allows the days she depicts to melt into dusk, the paintings come alive, newly magnetic and compelling.

The two largest paintings are her most complex and accomplished. Their long horizontal formats (26-by-66 inches and 26-by-70 inches) encourage a visual reading from left to right, a lateral passage through the scenes. Both begin with tame renditions of a suburban landscape--lawn and trees, in unmodulated daylight--but somewhere near the center, the compositions erupt into luminous, atmospheric states.

In “Forest Gate” (1987), the blue sky gives way to dusky pink and the staid green trees pass into animated auburn silhouettes. A house, innocent on the exterior but betraying a devilish glow from within, marks the border between the region of the familiar, cool and static, and that of the unexpected, hot and urgent.

An aura of intensity dominates the right side of the painting, where the foliage forms two dark, towering columns, framing a path to a distant glow. The left side is entirely safe, the right disorienting and slightly discomforting. While the smaller paintings are simply unpeopled, these larger works exude a sense of desertion and abandonment.

Preston exhibits the same skill at creating environments rich with atmosphere and mystery in her “Notations,” colored pencil studies for larger works. In both the abbreviated and expanded versions, Preston unleashes a great intensity from the most modest and unassuming of surroundings.

The show continues through July 11.

The unifying principle of the show “Black Lines” is not black lines at all, but, more generally, the use of black and white as the color parameters of a work.

The use of black and white to the exclusion of all other colors in itself signals a reduction, and many of the artists in the exhibit at Gwydion Gallery (formerly Viridian, 7825 Fay Ave., La Jolla) complement this reduction of means with a simplification of form.

In three paintings by Richard Allen Morris, among the strongest in the show, the paring down process has yielded an extreme refinement of line and idea. All three depict architectural structures, such as “Fat Building” (1971), and in each, the black lines defining the forms seem to exert a tensile force, pushing white space out or greedily holding it in. Within the most minimal means, Morris evokes the type of Kafkaesque structures that breed anonymity; their only concession to human inhabitants are doors and windows the size of mouse holes.

Other artists, such as Steve Ilott in his “Iceberg” series, and Tom Driscoll in his mask drawing, achieve more facile solutions, having begun with minimal concepts and kept them spare, rather than reducing more substantial ideas to a formal essence. Others choose a monochromatic palette to represent a stark reality or a dreamlike abstraction.

Robert Sanchez’s charcoal drawings of cell-like interiors feature furniture made of bones; here both content and form are basic and skeletal. Michael Cuddington’s drawings compress real and mythical space in a tight, frenetic network of line, and Italo Scanga’s convey a rawness of execution that defies the sophistication of their structure.

Despite its quality lapses, which few theme or group shows manage to avoid, “Black Lines” provides a good sampling of approaches to the endless possibilities that lie within the limits of black and white. Black itself is explored as both medium and subject, in paintings, drawings, diagrammatic renderings, shaped paintings and an installation. Other artists in the show are Peter Levinson, Mathieu Gregoire, Mari Andrews, Janet Cooling, Roberta Eisenberg, Amanda Farber, Jay Johnson and Ernest Silva.

The exhibit continues through July 18.