A retrospective of more than 50 years' work suggests that Patrick Scott's early career as an architect informed his artistic passion for order, clarity and precision, writes Aidan Dunne

For his retrospective, Patrick Scott says, he has repainted the walls in several rooms of the Hugh Lane Gallery. Nothing out of the ordinary there. It's common to apply a lick of white paint with each new installation. But, he explains, he has had each room painted a different colour. Different, and dark.

"I knew I wanted a dark background for the tapestries," he says, "but when I saw it I thought, that's what I want everywhere. Up until then it all seemed rather dreary. One painting after another. But this has made it much more interesting for me."

It's certainly dramatic. His elegant abstract paintings, mostly white and gold leaf on oatmeal linen, and his beautiful, more variously coloured tapestries are displayed against deep shades of blue, green and "bullock's blood". Not every room has a new colour. The early work, from the 1940s to the early 1960s, is arranged in a more conventionally pale setting.

Scott, who turned 80 last year, not only is one of the foremost Irish artists; he has also been a central, active presence in cultural life here since the 1940s, with myriad involvements in such initiatives as Rosc, the series of international exhibitions of modern art, and Kilkenny Design Workshops.

He was born in Kilbrittain, in County Cork. As he is quick to point out, he didn't go to art school, "so a lot of the early things are about trying out different kinds of paint on different kinds of background".

His first paintings, made during his association with the White Stag group - centred on a number of expatriate English artists during the war years - suggest the hand of a naive or outsider artist. "I was a kind of primitive, really, an Irish Grandma Moses." He was studying architecture at University College Dublin at the time. "My father went bankrupt. We were skint. The plan was that I was to start work with an architectural firm on September 4th, 1939. On September 3rd, war was declared, so no job. Then an aunt of mine very kindly gave me £1,000 to go and study architecture, and I lived on that £1,000 for the next five years.

"I never wanted to be an architect, though I quite enjoyed it. I always wanted to be a painter, but at that time there was absolutely no prospect of making a living as an artist."

He went to work for Michael Scott. Although they share a surname, they are not related. Did he opt for Scott because he was regarded as a progressive architect? "I opted for him because he was regarded as an architect who had a lot of work going through his office."

He immediately became involved in the design of Busaras, one of Michael Scott's best-known buildings, which, by virtue of changes of mind and government, became something of a saga. At one point the bus terminal's concourse was designated as a future women's labour exchange.

"I was deputed to do a perspective drawing, so I did a queue of aul ones with shawls. It looked totally ridiculous. But the buses got it in the end." Working full-time, he continued to paint. "But I could only manage about four or five paintings a year."

In his painting, he was clearly looking around, trying to figure out his artistic identity. Yet in compositions based on such motifs as a table, scaffolding and a deserted racecourse - the latter lampooned by Myles na gCopaleen in The Irish Times - his enduring concern for formalising space, his passion for order, clarity and precision, is evident.

The disks or globes that became a staple later on are intermittently evident from the beginning, most obviously in The Sun but also in the stylised head in Girl Carrying Grasses.

That is one side of his artistic character. The other is an apparently contradictory impulse to chaos and amorphousness. While there is a progression towards refining his pictorial language in the 1950s, a series of paintings inspired by bogland take him in another direction in the 1960s. "What happened was that, as an architect, I was working on John Huston's house, so I was back and forth to Galway on the train, and I saw a lot of bog out of the train windows."

He eventually figured out a way of painting it by using tempera on dampened, unprimed canvas. The blot and blur effect sparked an irreverently humorous response from some collectors. "I found that quite a few of my paintings had nicknames. Basil Goulding had one he called Bird Droppings At Eventide."

These two lines of inquiry are synthesised in some of his best-known work, the Device paintings of the 1960s. The devices in question were hydrogen bombs, and the paintings were made in a spirit of protest. Yet in combining the motif of the solar disk with the notion of vast explosive energy, the works significantly advanced the formation of Scott's artistic language and presaged his renowned Gold paintings. With the first of these, made in 1964, there is a leap to artistic maturity.

Their elegant, stringently simplified formal means exude a calm, and calming, authority, and their basic constituents have formed the basis for a rich body of variations since.

By the time of the first Gold works he was a full-time artist. Successful excursions to New York, in 1958 and 1960, and Venice, where he was among the artists representing Ireland at the biennale in 1960, not only boosted his confidence but also led to sales of his work.

Besides devoting himself to his work, however, he maintained a formidable schedule of related activities, working on the design of the first two Rosc exhibitions, and contributing significantly to the show's identity with strong catalogue-cover designs.

He was also heavily involved in Kilkenny Design. These and other design projects had in common the twin ambitions of opening up Ireland to international ideas and modernising and strengthening indigenous art and design.

Through his involvement with Sigma, a design agency, he used to do nixers. "The agency was Louis le Brocquy's idea, and Dorothy Walker was manager for the first couple of years. I was part of the stable of designers. I did the black, white and orange trains for CIÉ. I based the colour scheme on my cat, Miss Mouse." His portrait of Miss Mouse, included in the exhibition, was inspired by Bacon's popes.

He has long acknowledged the influence on him of Japanese thought and design, and he has visited Japan on many occasions. "My interest in Japan got a great fillip from my friendship with Morris Graves." An American artist steeped in Eastern thought and art, Graves lived in Ireland for some of the 1950s. "In America he lived mostly in Seattle, which is the next village to Japan, really."

When we met at the Hugh Lane, he was tired after working long hours on the installation of the exhibition. But he wouldn't have it any other way.

"It's always been fairly hands-on. I remember when we were slaving away on the first Rosc. On press day, there was the art historian Anne Crookshank, sweeping the floor of the RDS with a big broom just as the representatives of the international press were coming into the room."

Somehow, he has managed to cram several careers into one lifetime. It must have been hectic. "It never felt like that. I always just got on with the next thing that needed to be done."

• Patrick Scott's retrospective, which opens at the Hugh Lane today, runs until April 28th