The artistic vision of the 20-th century needed to be expressed in a completely different vision using unconventional painting and also sculpting materials.
Actually, materials referred to almost any existing object:
Extreme attempts of unconventionality belong to artists using mud, tar, excrements, soil and even blood as materials for their works.
Reputed painters using non-traditional materials include Braque, Rauschenberg and Picasso.
Help me improve this site: Send me your feedback. Thank You.