Research article and documentation on the making of opaque Venetian glass 15thc to 20thc and the use of opacifiers/which opacifiers were used when.
I've used an automatic translator - it should allow you to click the translate box at the top and do an automatic translation but for accuracy the document should be read in it's original language (my French is not good lol)
'Les verres opaques :la technologie des verriers vénitiens (XVe-XXe siècle)'
Cesare MORETTI ,
Chemist, Technologist Verrier
S.Vito al Tagliamento (Italy)
Stazione Sperimentale del Vetro, Venice (Italy)http://www.verre-histoire.org/colloques/innovations/pages/p202_01_moretti.html