PURPOSE: To obtain a glass product such as a milk or colored glass product by forming a tin oxide film on a glass substrate and further forming a milk or colored glass layer on the film.

CONSTITUTION: A soln. of a tin compound such as dimethyldichlorotin in a solvent such as dichloromethane is sprayed on glass substrate 1 from nozzle 2 and cooled in a slow cooling furnace to form tin oxide film 3 on the whole inside of substrate 1. The thickness of film 3 is desirably about 100W1,000. A dispersion of low m.p. milk or colored glass enamel in a liq. mixture of screen oil and turpentine oil is then sprayed on film 3 from nozzle 4. After applying this low m.p glass enamel coating, substrate 1 is subjected to ordinary calcination at about 550W660°C.