The "Volto" was the more common mask used in Venice for centuries. Very similar to the Bauta, the most used and almost "standard" mask for men.
Volto means "face" to design that is was the most common, simplest mask. Also called "Larva", with the possible meaning of "ghost", as it gives an eerie appearance to the people wearing it, just imagine ... at night, under a full moon ... in those narrow streets ...
As we may see in this watercolor, playing cards are scattered on the ground. Just brings us back to the fact that Carnival and Gambling went the same path.