Visual Arts:Paul Nugent is best known for his monochrome paintings, which, appearing entirely abstract at first glance, harbour underlying images that only become gradually and uncertainly apparent. It adds to the ambiguous hallucinatory nature of the experience that the images depict members of religious orders in full regalia, writes Aidan Dunne

In fact, part and parcel of Nugent's methodology was to dress models in the appropriate religious attire, photograph them and then make an accurate painted version, in black and white, of the photograph. The image was then over-painted with glaze upon glaze of a single colour, resulting in the unsettling, ghostly experience his work provides

In Vigil, his exhibition at Temple Bar Gallery, he has moved on from this procedure, though in a logical progression. All five paintings that make up the exhibition feature people or objects in architectural settings. The show's accompanying note reveals that the common setting is the Chapelle et Hôpital Pitié-Salpêtrière in Paris, a place that began life as an arsenal before it became a hospital - and asylum - for the destitute (mostly women). More recently it gained a progressive reputation for its treatment of patients with psychological problems, though the iconoclastic Michel Foucault, who made it the subject of his book The Birth of the Clinic, would not necessarily have agreed with that assessment. More recently still, it found its way into the news as the place where Princess Diana was taken after her fatal crash.

All in all, an ideally haunted setting for Nugent's consideration.

This time, the representational content of his work is far more visible than previously, though by no means straightforwardly so. In the first place, he establishes a disjuncture between figures and ground. The background spaces are rendered in the blurred photographic manner instituted by Gerhard Richter. They are also dark to the point of murkiness, as if recorded by night. Against their obscure depths, figures and, in one case, a chandelier, are picked out in pale line, as though we are looking at superimposed photographic negatives. The effect is also to make these historical presences - they are in period consume - ghostly and fleeting, flickering into brief life against the passing of centuries.

While the installation is quite spare, with just five works in all, it is atmospherically cohesive. There is a nice, cumulative sense of continuity. You build up a concerted impression as you make your way around the show. In juxtaposing positive and negative in single images, Nugent ingeniously continues his exploration of visibility and invisibility. He also evokes other dualities: consciousness and the unconscious, material and transcendental.

As with his earlier work, as well, these paintings can never settle down into an unambiguous pictorial space. If we settle on one aspect, it is immediately undercut by another, integral element, so that our eyes and minds are kept in a state of suspension, or continual negotiation. A view of an altar, in Deception, is notably effective in this context, setting a tone for our reading of the other paintings. Vigil is a rich and complex exhibition.

Chung Eun-Mo and Nathalie Du Pasquier share the two main rooms of the Fenderesky Gallery. Chung's paintings, featuring hard-edged planes of flat colour, might be described as abstract, but they also feel strongly architectonic, as though they relate to constructed spaces, and her palette and tonal range are atmospheric in a way that similarly evoke the fall of light on buildings, or across a town square, for example. Du Pasquier paints still life, but on a large scale, with bold colour and simplified forms, so that the objects are vivid and much larger than life, and an arrangement of, say, cups and boxes has a monumental, architectonic presence, as though it is an architectural vista.

So, although their work is distinctively different, the two artists do share some common ground, more than enough to make them good partners in the gallery. In a sense, both describe idealised spaces.

Both are based in Italy, and their work is very much in sympathy with that of the Italian metaphysical painters Morandi and de Chirico, both of whom evoke the same trinity of still life, architecture and abstraction. Chung very rewardingly likes to depart from a conventional square or rectangular format, and some of her best pieces see her engage in lively disputes with difficult shapes, drawing energy from the unorthodox format but constructing her pictures so cleverly that we can't tell that anything is out of the ordinary. Du Pasquier's paintings, with their spare form and absolute clarity of expression, are, on second glance, surprisingly subtle and problematic. They draw us into an apparently simplified world that turns out to be, after all, rather complicated. It is a very enjoyable show.

Watercolour is one of the most exacting disciplines in painting, because there is nowhere to hide: make an image with dilute, translucent pigment and the constitution of the work is all there to be seen. The definition can be stretched, of course, to incorporate more forgiving variations of the medium, allowing the use of body colour and pastel, as in the Water Colour Society of Ireland's 153rd Exhibition in the Town Hall in Dún Laoghaire. It would be a great pity if the traditional skills of watercolour painting were to disappear, and happily, as long as the society survives it doesn't look as if they will.

There are very capable watercolour painters in its ranks: Nancy Larchet, John Coyle, Ken Clarken, botanical artist Wendy Walsh and George McCaw, for example. Some of the highlights of the show include Philip Davies's views of Connemara; Bridget Flinn's charcoal drawings; Liam O'Herlihy's photographically exact watercolours; Pamela Leonard's etching, Spanish Garden; Susan Sex's botanical study; Jean Clyne's busy pastel landscapes; and the late Chris Reid's fine etching Near Roundstone, Co Galway. (Two other members who died during the year are also represented: Eleanor Harbison and Harold Bird.) On the minus side, there are many mediocre pieces and, with some exceptions, a scarcity of really good drawing.

Vigil: new paintings by Paul Nugent. Temple Bar Gallery, until Oct 27.

Chung Eun-Mo and Nathalie Du Pasquier: Abstract and still life paintings, respectively. Fenderesky Gallery, Belfast, until Oct 26.

Water Colour Society of Ireland 153rd Annual Exhibition: more than 100 artists. Councourse, County Hall, DúLaoghaire, until Sat (closes 1pm on Sat)