In his mature works El Greco demonstrated a characteristic tendency to dramatize rather than to describe.^[2] The strong spiritual emotion transfers from painting directly to the audience. According to Pacheco, El Greco's perturbed, violent and at times seemingly careless-in-execution art was due to a studied effort to acquire a freedom of style.^[44] El Greco's preference for exceptionally tall and slender figures and elongated compositions, which served both his expressive purposes and aesthetic principles, led him to disregard the laws of nature and elongate his compositions to ever greater extents, particularly when they were destined for altarpieces.^[49] The anatomy of the human body becomes even more otherworldly in El Greco's mature works; for The Virgin of the Immaculate Conception El Greco asked to lengthen the altarpiece itself by another 1.5 feet (0.46 m) "because in this way the form will be perfect and not reduced, which is the worst thing that can happen to a figure'". A significant innovation of El Greco's mature works is the interweaving between form and space; a reciprocal relationship is developed between the two which completely unifies the painting surface. This interweaving would re-emerge three centuries later in the works of Cézanne and Picasso.^[49]

Another characteristic of El Greco's mature style is the use of light. As Jonathan Brown notes, "each figure seems to carry its own light within or reflects the light that emanates from an unseen source".^[50] Fernando Marias and Agustín Bustamante García, the scholars who transcribed El Greco's handwritten notes, connect the power that the painter gives to light with the ideas underlying Christian Neo-Platonism.

Source from: http://en.wikipedia.org/wiki/El_Greco#cite_note-Landon330-43