The Peppercanister Gallery's new show, Wall & Plinth, features small-scale works by 13 sculptors. That's unusual because we rarely encounter shows devoted entirely to sculpture. More often than not, sculpture is regarded as an optional add-on to paintings.

There are economic reasons for this. By its nature, sculpture is relatively expensive. A bronze, for example, entails the specialised and costly business of casting. It's important to say relatively expensive though, because in absolute terms sculpture is not usually that pricy when production and other costs are taken into account, for the good reason that artists and galleries know they have a battle on their hands to sell it.

This is not to say that commercial galleries are necessarily run by idealists or that sculptors have something against making a living. But often sculpture entails a degree of dedication and commitment that is above the odds, and Wall & Plinth does reflect that fact. In a way, it is a small survey show that spans several generations of Irish artists.

Although the work included is all current, John Behan's pieces still reflect his pioneering use of Irish mythology in constructing an indigenous school of figurative sculpture, something elaborated in the work of Carolyn Mulholland. Equally, Breon O'Casey's treatments of staple themes - animals, the nude - recall classical European lineage.

Brian King is representative of a generation that embraced emerging art forms in the 1960s and 1970s, including minimalist abstraction and environmental sculpture. Michael Warren is well-known for his monumental work and, strikingly, that sense of monumentality translates convincingly on to a much smaller scale. He deals in terms of two basic orientations, the horizontal and the vertical, each respectively dominant in the two fine pieces on view. Sharon Lynch deals with comparable concerns in her sensitively poised, elegant bronzes.

Eilis O'Connell, Eileen McDonagh and Deirdre McLoughlin all possess impeccable feeling for sculptural form, something hard to define but easy to recognise. All have produced beautiful pieces for this show, McDonagh adhering to symmetrical geometric figures in her Black Star and White Star. Both O'Connell and McLoughlin depart from the geometric, moving towards the organic, with possible references to the human body.

Graham Gingles is known for his constructed, complex boxes. The three in the exhibition are really exceptional, even by his own high standards, and justify a trip to the exhibition in themselves.

It's not an all-Irish affair. Robert Janz's brilliantly visualised animal figures, here cast in bronze, are amazing. Sonja Landweer's voluminous, patinated bronzes are characterised by a sense of space within and, in the case of one ensemble piece, between. Adolfo Estrada's remarkable painted wood constructions are architectonic, occupying a space somewhere between painting and sculpture with quiet authority.

The layout of the Fenderesky Gallery in Belfast, with separate spaces upstairs and down, makes it ideal for the double solo show format that has become a staple arrangement for curator Jamshid Mirfenderesky. That arrangement may be coming to an end as the Crescent Arts Centre, in which the gallery is located, is closing soon for extensive refurbishment and remodelling. The new Crescent may boast a different layout.

Happily, during building work, the Fenderesky - which occupies a unique and important place in Belfast's cultural landscape - will move to a temporary space.

In the meantime, one of the final double solos at the Crescent features an apposite pairing: Richard Gorman and Marie Hanlon. Gorman is a long- established abstract painter and printmaker, while Hanlon has a substantial track record as an abstract painter, though she has tended to be underrated and on occasion overlooked. In the last few years, a lightness of touch has entered into Gorman's work. Not to say that it was unduly serious beforehand, but abstraction can tend towards the sombre.

Gorman's paintings are spare, finely judged arrangements, usually featuring a few overlapping forms, all flatly painted and hard-edged. His palette has always tended towards nicely subdued, autumnal hues with a slightly retro quality, and such is the case here, although there is a playful brightness to some of the colours.

This playfulness also emerges in the bouncy, springy character of some of the forms. One could add that the energies of the compositions are only just held in check, as though Gorman relishes generating centrifugal forces that threaten to pull the pictures apart - and keep our eyes busy.

As it happens, the work Hanlon shows also has a playfulness, a levity, about it. Several of her titles refer to aspects of music and there is certainly something musical about her use of rhythmic patterns and looping, gestural lines. The titles also refer to other things, however, and it would be mistaken to view the paintings too much in musical terms. Often there is a sense of her avoiding or subverting the purity of minimal form and integral composition. That is, she undercuts any temptation we might have to read the paintings in terms of classical minimalist abstraction. And there is such a temptation because that is, so to speak, where she's coming from.

Where she is, on the other hand, is somewhere more ambiguous and flexible. Each painting makes a space that can be occupied in any one of several ways, so we have to adjust to a particular visual language or code in each case. One piece, a diptych, underlines this by offering us two complementary approaches side by side. It is called, interestingly enough, Alibi, and one panel features a net-like pattern that resembles an unravelling grid (a template for abstraction) and the other a lush, turquoise colour field.

Hanlon is exploring discontinuities and contradictions, and how a piece of work can accommodate them yet still retain some kind of consistency, still seem right. Certainly the paintings are consistent in terms of being thoughtful, engaging and inventive.

Wall & Plinth is at the Peppercanister Gallery, Herbert Street, Dublin 2, until Feb 20. Richard Gorman and Marie Hanlon are at the Fenderesky Gallery, Crescent Arts Centre, 2 University Road, Belfast, until Feb 15