The depth of the scarring depends on the number of layers of collodion used. After painting the initial scar pattern on the face, allow the collodion to dry for a couple of minutes. Apply successive layers of collodion to the scar, allowing the liquid to dry between applications. Each layer of collodion will deepen the scar. Vary the number of layers in certain areas to create the uneven effect of a badly-healed laceration.