RALPH Cowan, who has died at the age of 100, was my art teacher and mentor, as he was for literally generations of the boys of Allan Glen's School, Glasgow. Though everybody was well aware of his astounding talent as an artist, few knew that he was also one of the most astounding stained glass designers this country has ever produced and that his reputation in that field was of worldwide distinction.

Ralph was born in the Maryhill district of Glasgow in 1904 and obtained his initial training from his father before studying drawing and painting at Glasgow School of Art while he launched his own studio in 1925 with the sum of [pounds]24.

By 1936 Ralph had established a reputation as a leading designer in embossed and etched glass. His one-man show of that year in the McLellan Galleries received considerable press coverage. In 1938 he was commissioned to design what was perhaps the largest window, some 46ft high, ever executed in embossed glass, for Thomas Tait and Basil Spence's Scottish Pavilion at the Empire exhibition. As a result of this success, he obtained many commissions, including one forCunard's super liner the Queen Elizabeth.

But just as the Queen Elizabeth was quickly enrolled into war service, and his superb glass removed and stored, so too was Ralph Cowan enlisted - in the RAF. He spent the war years still drawing and illustrating for RAF training manuals and later worked on the radar system.

After the war there was little demand, in those austerity years, for art at all, especially something as decorative and arcane as stained glass. It was an age when very basic housing was all important and he became one of that lost generation of artists. They were bleak and fallow years for so many artists and designers.

Thus Ralph completed his studies at art school and entered teaching.

This did not stop his creativity however, and he continued to draw and paint - he was also a very accomplished painter and illustrator - and his interest in all the arts was enormous. Along with his wife, Nita, an actress and speech and drama teacher, whom he had married in 1935, he designed and wrote and directed for the famous Curtains Theatre from which many renowned Scottish thespians such as Duncan MacRae and Molly Urquhart graduated.

He continued to exhibit and in 1958 his exuberant and daringly modern windows for Broom Parish Church, Newton Mearns, were unveiled. The last time I visited the church I was shown around by a wellinformed church servitor.

"They're better than Piper's [John] in Coventry Cathedral, aren't they?" she said proudly.

Michael Donnelly, in his recent book on Scotland's stained glass compared Ralph Cowan's work with that of Ralph's contemporary Sir Robin Philipson and it is clear that both influenced each other.

Donnelly concluded by writing:

"In any of his chosen mediums Cowan is an artist to be reckoned with and any future histories which neglect his workmust be deemed seriously flawed."

This, 50 years after his talent had first been recognised by the art world, gave Ralph much pleasure. Despite blindness, he continued to exhibit and as late as 2000 had a splendid oneman show in the RSMAD in Glasgow.

As a teacher he was an inspirational figure, a tall, striking and handsome man with, and it seems improbable for the 1950s but I can assure you it is true, a magnificent shock of shoulderlength hairwhich he kept all his long life.

Many former pupils have very fond memories of Ralph Cowan and he was, rather touchingly I think, especially proud of having taught some prominent old boys including the writerAlan Spence, and indeed myself. At Allan Glen's, where he taught for nearly a quarter of a century, was a science and technologybased school Ralph took an especial delight in producing writers, artists and musicians like Gordon Bruce of the SNO.

His commitment to all the arts was huge and not only was he widely read, he was a very fine poet as well.

Living for many years in his house in Uplawmoor he and his wife were Quakers which goes some way to explaining both his sensitivity and his integrity. He leaves his daughter, Diana, and son, David, five grandchildren, and a recent - which much pleased him - great-granddaughter. And he leaves too those many former pupils, like myself, who owe so much to him.

Ralph Cowan, artist and teacher; born January 10, 1904, died December 31, 2004.