The colored powders used for the kalam are prepared from natural products only. The pigments are extracted from plants – rice flour (white), charcoal powder (black), turmeric powder (yellow), powdered green leaves (green), and a mixture of turmeric powder and lime (red). It often takes several hours to finish a kalam drawing with appealing perfection. Decorations like a canopy of palm fronds, garlands of red hibiscus flowers and thulasi or Ocimum leaves are hung above the kalam.
The figures drawn usually have an expression of anger, and other emotions.
Kalamezhuthu artists are generally members of communities like the Kurups, Theyyampadi Nambiars, Theeyadi Nambiars and Theeyadi Unnis.
The kalams drawn by these people differ in certain characteristics. The Kalamezhuthu is a forty-day ritualistic festival beginning with the first of Vrischikam (Scorpio) in most Bhagavathy temples in Kerala
The paintings of the Kalam commences with a ritual called Uchappattu (noon songs). The Kalam would be completed by evening. Vannan uses a stringed instrument called Nantuni. The Kurup who sings Kalampattu uses a percussion instrument with cymbals and gong as accompaniments. The Kalampattu is associated with some ritualistic dance performances.