Glossary: Glazing pictures

See also "Framing technical details". Watercolours and prints should always be glazed either in a frame or with clips. Without it the painting will become dirty and degrade. There are several types of glass that we use. 1. Traditionally 2.5mm float glass has been used in paintings. This is fairly lightweight and does not make for too heavy a unit. As the size of the painting increases it becomes necessary to use 3mm glass to give strength over the bigger area.2. Plexiglass. This is the new trend in glazing. Plexiglass combines the viual effects of glass without the danger of breakage. In recent times perspex was used but this had the problems of being easily scratched and turning milky in sunlight. We are sending out all our paintings in plexiglass to give our clients the best possible service.