A compleat treatise on perspective, in theory and practice; on the true principles of Dr. Brook Taylor. Made clear, in theory, by various moveable schemes, and diagrams; and reduced to practice ... Containing diagrams, views, and original designs, in architecture, &c. ... All originals; / invented, delineated, and, great part, engraved by the author, Thomas Malton.

  • Malton, Thomas, 1726-1801.
Date:
1778
Catalogue details

Licence: Public Domain Mark

Credit: A compleat treatise on perspective, in theory and practice; on the true principles of Dr. Brook Taylor. Made clear, in theory, by various moveable schemes, and diagrams; and reduced to practice ... Containing diagrams, views, and original designs, in architecture, &c. ... All originals; / invented, delineated, and, great part, engraved by the author, Thomas Malton. Source: Wellcome Collection.

    404/426 (page 296)
    296 KEEPING, AND AERIAL PERSPECTIVE. Book IV. Plate few Inches, which is abfurd; for, if that fudden gradation of effefl was conti- XLVIII. nuec*to tiie c‘i^aace of a few Yards, it would become totally black, before it was pofiible for the Air to have any apparent effect on it. Now it is far from being fo in Nature, which is obvious to any Eye; for, if the materials are clean, and of an even and uniform Colour (without which no judgment can be made) I will ven- Eig. S°‘ turc to a®-rm» that two Plane Surfaces (V and Y) parallel between themfelves, at feveral beet diftance from each other, and having a full Light on them, cannot be No. 2- diftinguilhed one from the other, nor fo much as the Line or Edge (AD) feen, at a proper diftance for delineating; provided the Light be not (on this fide) fo very oblique (as at S, No. 3 ) as to (hade the other, beyond where the Line OC cuts it. i fay, the Eye being fo iituated (at O) that the Angle C, appears to cut the receding Plane, at B, they will appear as one continued Surface. Ne- verthelefs, it may be necellary, in delineating, to make a diftindtion, in propor¬ tion to the Diftance; but, if the Plane V has Mouldings, &c. on it, being cut, apparently, by the edge of the other, the Line is fufficiently defined without it. As it muft be obvious, that no pofitive Rule can be preferibed, I (hall juft make a few obfervations, and conclude the Subjedt; and, with it, the Book. In refpedl of Magnitude ; it is evident, that Objedts mry appear, in Perfpedtive, -to have any proportion to each other, although not greatly diftant. For Example ; in Plate 27, of Chelfea College, the fartheft Building, with a Pediment, is not above two eleventh parts of the hither one (to which it is equal) in height; and yet it does not offend the Eye, nor appear at too great a Diftance. But, if the gradation of Light was in proportion, it would be too great; becaule, not merely the height is to be con- fidered, but the Iquare of the height, which would reduce it to the proportion of thirty to one; but where we (hall fix the ftandard for unity, I am at a lofs to devife. Now, if we were at twice the Diftance from the hither Building (the diftance between the two Objedts being fomewhat more than twice that) the proportion of one to the other, would not be much greater than one to three; the gradation of Light, in that cafe, would be nearly as one to ten, but one third part of the former. Yet, I p re fume, that in two Pidtures lo delineated, it would not be advifable to .make that difference in the effedt of Aerial Perfpedtive. In fhort, as it is abfolutely impoftible to fix any criterion to determine the Ratio of the gradation of Light and the effect of Diftance, but muft ever be at the dis¬ cretion of the Artift, 1 ftiall only obferve, that the Objedts in the Fore-ground, as the hither end of the Bridge (Plate 48) being fuppofed near the Piaure, muft have its parts diftindt andperfea, with ftrong Lights and Shades, which gradate to the other End. The Buildings on the Wharf, &c. fhould be lefs perfea, as they recede from the Eye. The Church, at a Diftance, the Trees and Hills, one be¬ yond another, muft confequently be lefs and lefs diftina, according to their Dif¬ tance ; till at laft they are fcarce diftinguifhable from the Sky. For all which, the Artift can have no other Rule than, carefully and judicioufly, to copy Nature (the .heft Miftrefs) which, in that Cafe, is not always uniform, but infinitely variable. F I N I S.