A scientific concept referencing what happens with the turning or bending of light when it passes betweem mediums of varying density. The over-riding value is light, and in painting, Refraction refers to the effect that one mass of color has on an adjoining mass according to the human eye. Artist Birge Harrison wrote of this phenomenon in his book "Landscape Painting", 1911 and described the "lost-edge appearance and a general diffusion of tone, thus giving paintings their atmospheric quality." Source: Richard McKinley, 'Overcoming Obstacles', "The Pastel Journal", October 2005.<br><br>The bending of light from one course in one medium to a different course through another medium of different refractive index.<br><br>Refraction is the change in direction which occurs when rays of light pass from one medium to another of a different density, as they do from air to glass or water. Or, the distortion of an image by seeing through a translucent medium. To refract is to cause such a change in the direction of light. Ophthalmology is concerned with the eye's refractive ability: changing the direction of light in order to focus it on the retina. An ophthalmologist measures this refractive ability, resulting in an accurate prescription for lenses which will optically compensate for the eye's inability to achieve focus.Also see angle, mother-of-pearl, point of view, reflection, refractory, telescope, and wavelength.