Describe the characteristics of the Technique in this artwork's Mosaic description.
The Mosaic was made using the opus vermiculatum technique, thus a light outline is drawn around the shapes using tesserae, which is contrasted by the dark black background. The river pebbles of different colors are stuck with each other with a great mastery. The plastic effect of the portrait is achieved by using several nuances of white pebbles, positioned in the model with an exceptional skill. Whereas the black lines are used only for modelling the portrait's main features.
nuances tesserae opus vermiculatum Mosaic