When sketching still life, how do you show the light and dark of glassware?

Glass is shiny, transparent, smooth surface and strongly reflective.

Normally, the objects that can be seen in practice and exams include glass wares, bottles, plates and so on. In the performance of the texture of glass when to seize its unique characteristics, glass objects of high transparency, to use the mouth and the bottom of the carving to strengthen the shape of the glassware, glass objects of the highlights and through it to see the background of the reality to be dealt with in place. These transparent places are the key to the performance of glass texture. Glass texture, light transmission is particularly strong, black and white gray distribution should not be as clear as other objects.