AVRIL Paton eyes up the workmen putting scaffolding on the building across the street with an unmistakable glint. Nothing lascivious at all, you understand, absolutely not; it's the tenement they're starting to restore that is the object of her flickering interest.

"I'm so glad they are doing that building up. When they get it done, and there are people in it, I may paint that, " she says, a smile lurking. "And there's one tenement down the bottom of Byres Road, above the Bradford and Bingley . . . if I was a commercial artist, I would go and do it, but I'd just be regurgitating stuff that's popular."

She's serious, but she's also teasing;

aware she has the art-loving public in the palm of her hand, gasping for another of those iconic paintings.

Images of Windows in the West hang in thousands of living rooms, and have circled the world on a hundred thousand cards. Avril wishes to be known, nevertheless, not as The Tenement Painter, but as The Artist Formerly Known as The Tenement Painter.

In two weeks' time, her exhibition, New Looks, opens at The Mitchell Library, her first for seven years.

Income from prints of Windows in the West and otherworks has bought her the time and freedom to change direction artistically.

Seventy works will be on show:

the new - dreamy, slightly surrealist pastel and oils; and the old - among them the only two large-scale tenement paintings she has done, Windows in the West and Bedsits. The former is in the possession of Glasgow Museums and Art Galleries; the latter is now for sale, for a price and with an excitement which can only be imagined.

Like a typecast actress, Avril is torn between the new, where the challenge is, and her affection and gratitude for the old. "I have gone in a different direction because the prints support me and give me the freedom to move on as an artist. If an artist doesn't develop they are dead. An artist is about the soul, not about making money.

"I'm trying to break free of being the artist who does Glasgow tenements. I may never do another. What artists want to do is communicate.

It's a big thrill to me - someone asked me yesterday for my autograph - but the downside is that people want you to go on doing the same thing."

She sees herself as a loner in the art world, and it makes her sad. There is in herwork, as in her life, the sense of being on the outside looking in; symbolised in no small part by her upbringing on Arran. Her father, Hugh Paton, and her grandfather, Donald Paton, were both landscape painters on the island. Mandi Gillies, her mother, who died recently, met and married Hugh when they were both at Glasgow School of Art in the late thirties. Avril was born in Glasgow in 1941 during the wartime blitz.

She is successful now, but her life has not been easy. She started at Glasgow School of Art in 1958 but life got in the way. Avril returned to Arran as a single mother to raise two daughters. It was 20 years later, in 1982, this time with a young son, that she went back to Glasgow.

Her plan was to re-apply to art school, but the late John Cunningham, distinguished painter and tutor, told her she was wasting her time:

that she already had her style and shouldn't jeopardise it. He advised her to start mounting solo exhibitions.

So, "I started painting Glasgow."

She fell in love with Paddy's Market, the subject of some of her famous early work. "It was the most amazing place at the time, exceedingly scruffy, chain link fences hung with rags, torn by the wind, much more like a scene from the Victorian era. And the faces, the people. I couldn't believe it. Walking down from Argyle Street was like walking through time."

And here, too, a recurring theme in herwork, an almost Dickensian love of observing people. "At first I went with a sketch book, but had to stop that as people thought I was DHSS.

Instead, I would go to a snack bar and do sketches from my head."

Like Dickens, she walked: east end, west end, the Barras. In 1988 her painting The Barras was bought by GlasgowArt Galleries and Museums - her first major sale and the one which to a large extent established her credentials as an artist.

Her interest had begun to switch from the people to the buildings themselves. It was the stuff of minutiae; intricate, time-consuming work.

"The first tenement picture, called The Tenement, I did when I was living in Glasgow Street, in Hillhead.

My flat looked out over a big courtyard. I could see into people's dwellings all around me.

"I did it for a show I was having.

I was very disappointed with it; it didn't represent what I wanted. I was very cross with myself. When you paint in that time-consuming manner you haven't got time to make mistakes. Always you are only as good as your last painting, and it sets you back when you do a bad one . . .

"Anyway, The Tenement went into the show and it flew off the wall. I could have sold it 20 times. It took me some years to work out why I didn't like it. It was from an architectural perspective, and an architectural perspective doesn't always look real.

"To make it look real needed incredible discipline and hard work, and that was all anathema to someone who wanted to throw the paint at the canvas. It was all highly disciplined and I didn't want to do it. In the end you have to go where you are meant to go."

Then came Windows in the West, born out of a bad situation. Avril had a friend in the then-Hillhead Housing Association, which had refurbished a town house in Athole Gardens as amenity housing for elderly ladies. They needed a caretaker, the caretaker got a one-bedroom attic f lat, paid half rent, and kept the place clean. For Avril, it was a lifeline.

It also made herworld famous. On January 11, 1993, at 5.30pm, there was a heavy blizzard. Avril peered from her little high windows overlooking Saltoun Street and saw a tenement transformed - lilac pink sky, lighted windows, clarity of whiteness, lots of people at home. The idea for Windows in the West was compelling.

The first drawings were done in February; it was finished by the end of June. But this most loved of Scottish pictures almost never happened.

"I didn't intend to paint it all, it never crossed my mind . . . the sheer architectural effort. I set out to do the bit of the building with the drum windows on it. When I was about to transfer on to the final paper, I realised I had made a mistake with the size of the paper. At that time I was terribly poor . . . buying a birthday card for someone was a real problem. Buying art materials was difficult. I was upset that the paper was the wrong size.

"My son Max came home from school and I wondered whether I should abandon it and start again and do the whole damn thing - and he was about 15 and when I asked him he said: 'Oh it would be great if you could pull it off!'He threw down the gauntlet."

The finished work was 4ft by 5ft, painted with gouache, egg tempura and watercolour. It took over the little flat. "You couldn't move for the thing. It wasn't safe to have it hanging around on paper, so I had it framed. Then I discovered people's reaction - it got a huge response.

People were raving about it. I didn't exhibit it for another year, but I couldn't keep it in the f lat, so eventually it was hung in the concert hall."

The public response was overwhelming and the picture was bought by the city for pounds-10,000. Given the time she spent on it, Avril remarks wryly that she would have got more working in Safeway. Windows hung in the Gallery of Modern Art for nearly 10 years, where it was the most looked-at exhibit.

It is estimated that well over 30,000 prints, and more than 100,000 cards, from the painting have been sold.

Why was it so popular? Partly because it has a warm Christmassy feel. Partly because it is an open face which contains so many closed worlds, glimpses of people's private lives. Even as you enjoy the sense of place, you understand there are thousands of unknowables in it.

Who are these people? What are they saying?

She was suddenly famous, but she was still a caretaker for the old ladies.

"I remember coming back from the television studios where I had been doing an interview, and the ladies pounced on me for not cleaning something. It brought me back to earth. Those were happy times. My time in that f lat was one of the most important periods in my life, because the ladies needed me."

Ten years on, she is financially secure and trying to move on. "I haven't distanced myself from it; the picture has distanced itself from me.

It's like a child. It goes off and leads its own life."

In her career she has done only 10 tenement paintings, eight of them of sections - roofs, individual windows.

Bedsits, painted from the kitchen window of her lovely corner f lat overlooking Ruthven Street, is only the second she has done of an entire building.

"I did Bedsits because it was there.

I don't do commissions of tenement work. In order to do that sort of sustained effort, you have to have a powerful connection with the subject.

Bedsits was terrific fun to do, but it's nothing like as good a painting as Windows in the West.

"What is it worth? If Windows in the West was for sale now, it would go for not less than pounds-100,000, so what do I sell this one for? It's not as good as Windows in the West, it's not iconic, it's not the same picture, but it's selling extremely well and the prints are extremely popular."

She smiles again, teasing. She says her accountant has told her to stop doing tenement pictures, because they take too long to do and make too much money. Avril Paton, an artist who has endured more than a few hard times in her life, deserves her success. She deserves, too, the room to distance herself from Glasgow in her art, even as she remains inseparable from the city. Ever the acute observer, The Artist Formerly Known as The Tenement Painter sees it all herself far, far too clearly.

New Looks is at the Mitchell Library, Glasgow, March 11-April 16. A percentage of profits goes to the charity Enable. Avril is gifting the entire proceeds of her picture of two ladies visiting an Edinburgh art gallery to the charity.