Ukwazisa iperi enomtsalane yeeglasi zeglasi ezisikweri ezenzelwe ukutshisa isimbo sakho.Ezenziwe ngesakhelo somgangatho ophezulu we-acetate, ezi glasi ziqhayisa ngombala otyebileyo nocacileyo odibanisa izithunzi ezimnyama, iipateni eziluhlaza kunye nebrown.