The Oxford Dictionary of English (3rd edition) defines “flatness” as “the quality of having a level surface without raised areas or indentations,” as a “lack of emotion or enthusiasm,” and as a loss of something: effervescence in a drink, air in a flat tire, or charge in a battery.
Peppered in the entry are lacks: whether hills, bubbles, emotions, or body fat (“I am transfixed by the flatness of her stomach.”)
Flatness, then, can be seen as a lack (of something). When we stroll into a paint & hardware for “flat” paint, we buy the tins with the most pigment, and so, least reflective properties. A “flat” paint lacks shine. A “flat” colour lacks dimension. A “flat” picture lacks depth.
In “Modernist Painting,” first published in 1961, American art critic Clement Greenberg argues that flatness is the defining characteristic of modern art, for it is flatness that was “unique and exclusive” to pictorial arts. Colour was shared with theatre and with sculpture (the latter of which did dimension better). What pictorial arts shared with no other is its medium: the canvas. Modernist painting declared the flat surface, previously cloaked in illusion under Realism.
“Flatness.” Oxford Dictionary of English, edited by Angus Stevenson: Oxford University Press. 3rd edition. 2010. https://www.oxfordreference.com/view/10.1093/acref/9780199571123.001.0001/m_en_gb0998733 Accessed 21 September 2020.
Greenberg, Clemens. “Modernist Painting.” Modern Art and Modernism: A Critical Anthology,
Modern Art and Modernism: A Critical Anthology, edited by Francis Frascina and
Charles Harrison, 1982.