Light is the body in painting of the first magnitude and | Reflection the medium or in other words the half light while | shade is the deprivation of light only but with the | deprivation of Reflection likewise it becomes Darkness | There is nothing new in this position but the last | or difference between shade and darkness. The | former has been accomplished by the greatest masters | from Titian’s bunch of grapes where each grape | was considered as a ball just the central or | focus of light was concentrated | upon a point then | half light or Reflections intervening between the two | and shade if shade it can be called that admits | of so large a portion of surrounding light and | ½ tint. We therefore refer to the Portrait of | Vandyke of the Dutchess [continued on folio 16] of Cleveland (dark Green) as the most instructive | for the advancement of Study. to the greatest | part of the Globe on which | the figure leans in the | character of St Agnes partook partly of | half light a central | speck opposite to the | sapphire ray of light and the reflection opposite | the shadowd part ... between from | which is resting upon a base from which | the light strikes it the ball receives a | reflected light another but lower in line | opposing it so that when I [? have] to define the | light and shade it would be right to admit a reflecting and reflective light. [continued on folio 17] Refracted lights are those received by all | bodies, but most so by polished ones from all | surrounding objects both of light and shade | and of course where refraction is concerned | shade must become more circumscribed | Refracted lights give clearness and by their | help objects can be more defined. by a | judicious introduction but they destroy | force. Rembrandt is a strong instance | of caution as to reflected light and | Correggio to refracted light. Two instances | of the strongest class may be found in the | celebrated pictures of the Mill and La Notte. [continued on folio 19] The Mill has but one light, that is to say upon | the Mill, for the sky, altho a greater body of | mass is reduced to black and white, yet is not | perceptible of receiving [the] ray by any indication of |form, but rather a glow of approaching light | . But the sails of the mill are touched with the | incalculable ray, while all below is lost in in | estimable gloom without the value of reflected | light, which even the sky demands, and the | ray upon the Mill insists upon, while the | ½ gleam upon the water admits the reflection of the | sky. Evanescent twilight is all reflection but | in Rembrandt it is all darkness and gleam of light | reactive of reflection. Refractions [are] occasioned | aerially. [continued on folio 20] The Notte is all light and shade in Darkness. | But as a solitary instance from a great master | may appear contrived, and caution of allowing | his knowledge in light and shade, let me draw | another instance of that knowledge in another | picture the Cradle, here, where Reflections &c | become only powerful in a concentrated | ray; and Refraction [and almost Reflection inserted] ceases except in bodies that | admit the first light. He becomes the master of | artificial light and shade, let me suppose it | be understood as those lights that are artificial | and not those beams that give light vigour | and animation to the uneventful. Their effect | in an abstracted sense is as distinct as this [continued on folio 28] appearance. Nature it would be wrong to say | as we can but know but one: the rays of the | sun strike parallel, while the candle | angular. One destroys shade, while the other | increases it; and as reflection and refraction | are increased by the influx of light, so are | they concentrated by an excess of shadow |, produced by the light becoming a focus |. The art of the Picture therefore is only and | properly light and shade; the greatest | shade opposed to the greatest light, as | ... the Mill is otherwise than the opposition of the light depicted
For Turner’s fifth lecture see especially Davies 1992, pp.50–3.
Gage 1969, p.271 note 2; the source is in Edmond Malone ed., The Works of Sir Joshua Reynolds, 2nd ed. London 1798, note XL.
For Turner’s comments on this portrait in his fifth lecture, see Davies 1992, p.53.
Martin Butlin and Evelyn Joll, The Paintings of J.M.W. Turner, revised ed. , New Haven and London 1984, pp.61–2 no.81 (pl.91). The Unpaid Bill and The Holy Family at Night were exhibited together at Tate Britain in 2009; see David Solkin ed., Turner and the Masters, exhibition catalogue, Tate Britain, London 2009, pp.148–9 reproduced in colour pls.41, 42.