FORM is the theme of Pyramid Gallery's new exhibition by the late Sir Terry Frost and Sandra Blow and the London Glassblowing Workshop, opening on Saturday at 11am.

"For each of these artists, the work can be easily identified from the aspect of form alone," says Terry Brett, director of the long-running gallery in Stonegate, York. "But the visitor will first notice the colours, bright swirls and stripes of vivid colours in Frost’s collaged prints, and geometric blocks of colour in Blow’s screen prints, complimenting a myriad of colours and forms in the glass vessels and sculptures."

Sir Terry Frost (1915-2003) was a giant of British abstract art, who left school in Leamington Spa at 14 to work at Curry's Cycle shop. He served in Palestine and Greece in the Second World War before being captured in 1941. He remained a prisoner of war until 1945, an experience that changed his outlook on life and introduced him to art as he began to paint and draw in prison camp in Bavaria, encouraged by young artist and fellow prisoner Adrian Heath. "I got tremendous spiritual experience, a more aware or heightened perception during starvation, and I honestly do not think that awakening has ever left me," he said later.

Londoner Sandra Blow (1925-2006) was a leading lights of the abstract art movement of the 1950s. Her often large abstract collages are made from cheap discarded materials, such as sawdust, cut-out strips of old canvas, plaster and torn paper, to create informality and a natural, organic feeling. They have a tactile quality and their geometric shapes give them dynamism.

Born to a Kent fruit farmer whose orchards supplied retailers in Covent Garden, Blow left school at 15 and entered St Martin's School of Art in 1940. Shortly after the Second World War, she studied at the Royal Academy Schools, but in 1947 she ventured further afield, living in Italy for a year, where she met Alberto Burri, who was to become a significant influence on her work for the rest of her career.

Showing alongside the late Royal Academicians Frost and Blow will be an exhibition of glass by Peter Layton and nine associates of the London Glassblowing Workshop, marking a 30-year association between one of Britain's first contemporary glass studios and Pyramid Gallery. "Their show celebrates the many techniques and varying forms that the art glass makers exploit in their work," says Terry Brett.

The On Form exhibition runs from Saturday to July 7, open daily from 10am to 5pm, except Sundays, when the hours are 12 noon to 4.30pm. Several of the glass artists will attend Saturday's 11am launch; all the work on display is for sale and most pieces can be viewed online at pyramidgallery.com