With Control/Corrupt, the Paul Kane Gallery has come up with a cracker of an exhibition. Regular visitors to the gallery will know that it specialises in staging two simultaneous solo shows, a logical use of its two handsome first-floor rooms.

The degree of interaction between the two varies, but this time around they complement each other perfectly. And, as it happens, the dual format is all the more appropriate because one of the artists, Megan Eustace, has an identical twin, something mentioned here not as a miscellaneous snippet of information but because it has been relevant to her work from the beginning.

Eustace has remarked on this herself, but if she hadn't we wouldn't necessarily be any the wiser on the basis of what we see in the gallery. She doesn't, for example, explicitly deal with the exotic mythology and perhaps even more exotic facts of identical twins. What the experience of being a twin seems to have done is to engender a fascination with questions of what it means to be inside oneself as an individual, to be an individual at all, to be whole, and to be separate. Her images suggest a continual questioning of her own experience of the world in those terms.

That, at any rate, is one way of interpreting her continual use of fragments, ellipses and handwritten texts which are often illegible, and the oblique, introspective quality of what she does. It is as if we are seeing glimpses of an essentially personal, private journal in which drawing is the primary means of recording experience. While Eustace does paint, drawing is really what she's about. She is not a brilliant draughtsperson, but perhaps more importantly, she is a good one who has real feeling for the medium: even a casual sketch is infused with nervous tension. And she's good at giving her work a history, generating worn-looking colours and textures.

Eustace's co-exhibitor, Gabrielle Quinn, is another artist of strikingly singular vision. She makes beautiful, minutely detailed drawings and startling sculptures which, in their intense, trance-like absorption and utter concentration on a subject recall the work of Paul Mosse, particularly his earlier drawings with an explicit subject matter. As with those images of his, things are scrutinised to the extent that they become strange, and rendered with limitless patience and calm. Quinn tends to push an ambiguity that verges on the surreal, blending disparate ideas and things. It's all very understated, even the more overtly garish sculptures: you have to give it time.

From introspective drawings to up-front paintings, Toru Kamiya's exhibition, at the Temple Bar Gallery, makes a strikingly good installation. Specifically, the small canvases arranged as a continuous band around the wall at eye level are a very strong work: a long sequence of intense colours which merge into each other or meet edge to edge.

The automatic temptation is to follow the sequence from left to right, to read it like a text or, more accurately, a narrative in colour. It is extremely rewarding to do so. Colour is never neutral, and if you let your eyes roam and your brain respond you'll find the effect is surprisingly intense. But apart from its emotional impact, the work generates a sense of time, something that is quite intentional on Toru's part, for it is a kind of visual diary, a record of passing time. For him, art is integral to life. Even within single-panel pieces, the modulated colour suggests change and also the continuity of cyclical rhythms.

By co-incidence Toru, who has spent a year at NCAD on a scholarship, and another young artist, Paul Doran, whose exhibition at the Hallward Gallery has just ended, approached me at more or less the same time and asked me to write brief catalogue notes for their exhibitions. It struck me that in both cases their work is dominated by colour and process, approached in different, though related, ways.

Toru's approach is certainly influenced by Japanese cultural tradition, with its ritual, aesthetic attitude to almost every aspect of life, from making tea to looking at cherry blossom. In the utilitarian West, and, for that matter, in the westernised East, much less value is placed on such considerations.

Doran's work comes into the category known as "process painting", that is, painting in which we are prompted to regard the painting itself, and the discipline of its making, as the substance of a work. Rather than being as reductive as it might sound, by draining painting of the capacity for conveying meaning, for example, this arguably directs us to an appreciation of things in themselves and actually heightens our attentiveness to the world.

Like Toru, Paul Doran uses brushes as wide as the paintings he makes. They consist of generous swathes of thick colour, usually painted wet on wet. Texturally, his work recalls that of English artists Jason Martin and Zebedee Jones, but in the luxuriance of his colour and his belief in ocular pleasure he is closer to Howard Hodgkin. Both Toru and Doran, in their diverse ways, exemplify a growing and interesting trend among younger painters to make paintings using minimal form and with the emphasis on process.

Control/Corrupt is at the Paul Kane Gallery until September 4th. Toru Kamiya is at the Temple Bar Gallery until August 27th

Last week, working from an advance copy of the Sculpture at Kells catalogue, I gave the closing date as August 24th. This was later amended to August 29th