The bronze artwork springs from the prototype made by the artist.
Today, even though some artists still prefer clay, the material most frequently used is plasticine, as it doesn’t dry as quickly, hence allowing the artist to modify the sculpture after time as well.
Once the sketch is ready, the sculptor needs to create another copy, in chalk. This is a very important passage because the clay or plasticine model, being softer, can deteriorate upon pressure. Chalk instead is a much more resistant material, does not alter when handled, and does not deteriorate with time, becoming a prototype that can be saved by the artist and should the opportunity arise, be reused in the future.