Sometimes called 'Sugar glass', the distinctive texture was created using a technique of glass enamels called 'Crinkles' which was patented by the Johnson Matthey company in 1938. It was probably also used by Kristalunie Maastricht to produce the Oranje-appel vaas by W.J.Rozendaal in the same year. After the war it was sold to glass factories under license in various countries, including Chance Glass (UK).
After the war, (and Kristalunie's decision to abandon the product), de Rupel produced these colourful textured glasses in large quantities. They are an iconic element of 1950's table glass.
The individual layers for crinkles and gilding were applied by hand, and although most Boom glasses seem to have four glided bands at the top. The glasses were made in a wide range of colours, which were probably selected 'to order' according to the wishes of wholesale buyers. Design and colour choices were to some extent also left to the individual decorators.
Tim