Diana Horowitz is a deeply appealing painter. She works within the tradition of open-air painting dear to artists from between the 17th and 19th centuries. Making gracious use of her antecedents, she balances the improvisational appeal of plein air against the demands of unromantic modern construction. This, her second exhibition at Hirschl & Adler, is a medley of 20 or so cityscapes of New York and several pastorales of Truro.

Ms. Horowitz’s industrial sites along Brooklyn’s commercial waterways are not tourist destinations. The Gowanus Canal, once close to derelict, lingers as an unremarkable relic of the vital shipping hub that it used to be. The artist’s reserved and modulated handling of it gives back to the site a certain pride of bearing appropriate to an inlet explored by Henry Hudson and Giovanni de Verrazano. Each of these urban views carries a strong sense of the presence of the painter, of a selective temperament drawn to beauty in the structure of things.

In “Green Tanks” (2006), a row of pale viridian silos reaches across the middle ground. The foreground stretch of water, pale as the sky it reflects, acquires a subtle pump of color from the additional reflection of the silos. The rhythmic punctuation of a series of red shipping containers, seen at a distance as tiny rectangles, emphasizes the dark horizontal line of the loading platform.

Painting from direct observation, Ms. Horowitz necessarily limits the size of her canvases and panels. She keeps them portable so that she can return as often as needed to a chosen site. Her downward panoramas of the city, seen from a height — “Ann Street Viewed from Above” (2007) and “East View on Vesey” (2007) — compress scenic detail with enviable economy.

There is strength in Ms. Horowitz’s lucidity and ability to convey a great deal of information in a contained space, and with a minimum of brushwork. “Yellow Smoke Stacks” (2006) is a jewel of a thing, less than 6 inches square. Yet the chromatic range, the interplay of suggested and depicted detail, lends the piece a sweep and a solidity that many painters do not achieve on larger canvases. “Uptown, Summer” (2007) is a convincing evocation of the city seen through a curtain of haze.

A surprising addition to this show are several small abstract paintings interspersed among the artist’s signature motifs. But these are not quite the anomalies they first appear to be. They are keyed tonally to the plein air paintings; their complexion remains the same. “Night Study” (2007) is just what its title suggests: a movement of nighttime tones that play across the canvas, untethered to a locale. Here are the same rich darks — enlivened by a mixed black instead of one from the tube — that lend weight to “Black Building, Carroll Street” (2005), a view of the Gowanus. “Red Grid” (2007) makes a feast of variegated inflections of the same cadmium red that heats the foreground of “Wallabout Basin from Kent Avenue” (2005).

Tranquil and delicate, these abstractions carry less conviction than her depicted scenes. Each composition hovers over a faint, shifting grid that suggests spent emotion — as if the image had evaporated, leaving behind some stain or imprint of its presence. Lovely color floats on a silken surface that bypasses pictorial structure. Ms. Horowitz is still feeling her way toward an internal architecture to support her chromatic agility.

Until March 15 (21 E. 70th St. at Madison Avenue, 212-535-8810).