Gumn was born in Ynysybwl, South Wales in 1921. He was the son of a coal miner and the eldest of eight children.
After leaving school he moved to Salisbury and took up an apprenticeship at the Wessex Firework Factory, a job that would lead to his involvement with the printing industry.
After serving in the RAF during the Second World War, he founded BAS Printers in 1949, in a shed next to his cottage in Over Wallop. By then he was a commercial designer at the firework company, and the printing business was initially set up to produce firework labels.
In 1959, Gumn was approached by the Monotype Corporation with a proposal that he should purchase a Monophoto filmsetting system, which was in early development at the time.
His son Paul Gumn said: “This was an enormous investment by such a small company, but he went ahead and BAS became a leading typesetting house, producing high volume typesetting for London publishing houses.
“Three of his brothers joined him in the company in those early years. It was recognised that by using the Monophoto system for printing in litho, illustrated monochrome bookwork could be designed with illustrations on the relevant page with the text. BAS quickly built up a reputation for high quality short run specialist books in black and white by developing a system using first generation film of both text and images, integrated in their ‘sandwich positive’ process.”
For the following 25 years this work was the mainstay of the company, which employed up to 95 people at its peak.
“At times, family members made up 10% of the workforce,” Paul Gumn added.
“My father retired in 1981, so was able to enjoy a long and happy retirement, having time to pursue his interests of photography and painting.
“He also saw the introduction of colour printing in the 1980s that took the company into becoming one of the leading printers of art exhibition catalogues in the UK.”
BAS was sold by its second-generation family owners in 2002.
Gumn is survived by his wife of 72 years Frieda, three daughters and a son, eight grandchildren and 14 great-grandchildren.
The funeral will be held at St Peter’s Church, Over Wallop, Hampshire at noon on Wednesday 3 April. This will be followed by refreshments at the Parish Hall.
Flowers are welcome, or donations can be made to Alzheimer's Research UK. Either can be sent via S&J Maddocks in Andover (sjmaddocks.co.uk).