Visual Arts: Evie Hone: A Pioneering Artist is a modest tribute to the painter and stained glass artist whose name is generally uttered in partnership with that of Mainie Jellett. Hone and Jellett were the Butch and Sundance of early modernist art in Ireland, a pair of outlaws bringing back dangerously innovative ideas from decadent Paris.

Relatively speaking, that is, for they were unlikely outlaws: very strait-laced, the version of Cubism they practised was tame and academicised, and both are probably best known for work that is religious to varying degrees. Hone's faith became increasingly important to her: she converted to Catholicism in 1937. As curator Sighle Bhreatnach-Lynch notes in her brief text, she was dogged by serious ill health throughout her lifetime and she died, on March 13 1955, as she was entering her parish church in Rathfarnham.

This current show marks the 50th anniversary of her death. It just about made it, beginning last month and running until March. It is, though, an extremely, even perplexingly modest affair. If you are going to go to the trouble of organising a Hone exhibition, why not do it whole-heartedly? As it is, confined to one, not especially good, room in the gallery, it comes across as something of an afterthought, and it really doesn't contain enough work. The problem is one of scale: as far as it goes, the show is well done and well presented, but not enough resources have gone into it.

Though a member of one of Ireland's foremost artistic families, Hone battled personal difficulties from early on. Infantile paralysis left her lame and impaired the use of one hand. When she and Jellett went to Paris in 1920 they studied first with Andre Lhote and then with Albert Gleizes. Fascinatingly, one of Hone's sketchbooks, inscribed with some of the neat, meticulous exercises prescribed by Gleizes, is on view.

One must admire the care and fastidiousness of her draughtsmanship, but there is no getting away from the fact that the mechanical quality of Gleizes's rotational geometry effectively kills Cubism stone dead. In the hands of Picasso and Braque, Cubism was always much more than a pat formula for fragmenting and rotating form and colour. There is something exciting, inspired and incalculable about what they did with dry theory.

Hone was not as adept as Jellett at taking a formulaic approach and making something interesting of it. Her nominally Cubist works come across as stilted and, despite the colour and radiant patterning, fairly inert. Jellett was perhaps more inventive within the confines of the formula. But then, to be fair, we would need to see a great deal more of Hone's Cubist paintings to get a clear of idea of what she managed to achieve. And that would take an exhibition on a greater scale altogether.

What does come across is that she was a great deal more relaxed with the free, loosely representational approach she subsequently adopted, even as she was exploring the rigid constraints of stained glass design through her work at An Tur Gloine and in her own studio. She did a great deal of work in stained glass, much of it very good, and some of it outstanding, including her huge Eton College window, widely regarded as the peak of her achievement in glass.

While her paintings, with their use of black outline and bold colour, reflect the influence of her experience with stained glass, there is something attractive and distinct about them as well. Her many landscape studies have a vivacity and airiness that is very appealing. It is as though she responded gratefully to the relative freedom of paint and brushes, allowing herself a spontaneity and latitude otherwise held strictly, even severely, in check. In views of Marlay and Youghal, she is more unbuttoned and attentive to the character of what she sees in front of her.

Mark Joyce's Lux Clara at Green on Red comprises a series of 18 small paintings, made with acrylic on gesso, mostly panels. An engaging and discursive fold-out catalogue offers what seem to be excerpts from the painter's notebooks and two lists: a list of painting titles and one of 41 colours in the studio 20 September 2003. There is, as well, a short Prologue, in which he recalls, at the end of 1991, a moment of epiphanic realisation.

A painter who had come to doubt painting, he was "in complete free fall". In Monchengladbach, he went into the Museum to see what paintings were there. Looking at a sequence of pictures, he feels suddenly overwhelmed. "I had finally got it . . . Colour was the subject of painting." Certainly the paintings in Lux Clara foreground colour. Their basic unit of construction is the colour stripe (with some lively excursions into blobs).

Each line is laid on in a single, fluid movement. The pigment is partly transparent, something enhanced by the dry white powdery gesso base coming through the layer of colour. Classical oil paintings consolidate many layers of opaque colour and transparent glazes into a robust, convincing illusion of pictorial depth, physicality and coherence.

The show's title, and his methodology, suggests that Joyce is standing back from this, giving consideration to something that is incorporated in the illusion: light.

It's as though he wants to preserve a sense of colour infused with light, colour floating in the air, rainbow-like. And there is a tremendous lightness to his paintings. While they are small (like so much contemporary painting), and while they are materially simple, they have terrific presence.

They actually need space around them, so they can float freely. While they are to some extent reductive, they also evoke surprisingly elaborate and wide-ranging references, from Amelia Earhart to Thomas Tallis. It could be that by allowing in so much, Joyce is emphasising their implication in the world, making sure that we don't think of them as exercises in formalism, rather as part of an ongoing conversation or debate. It is a good-humoured, though also, in the best sense, a challenging show.

Reviewed: Evie Hone: A Pioneering Artist National Gallery of Ireland, Room 20, until Mar 11 (01-6615333)

Lux Clara Mark Joyce, Green on Red Gallery until Feb 4 (01-6713414)