This keyboarded and encoded edition of the work described above is co-owned by the institutions providing financial support to the Early English Books Online Text Creation Partnership. Searching, reading, printing, or downloading EEBO-TCP texts is reserved for the authorized users of these project partner institutions. Permission must be granted for subsequent distribution, in print or electronically, of this text, in whole or in part. Please contact project staff at eebotcp-info@umich.edu for further information or permissions.
Farther Precepts about Light.
IT is a General Rule that the Lights must be given to Bo∣dyes according to the place through which they pass, and this must be order'd so that the Light do ever Touch more suddenly on the middle Line, supposing that part of the Bo∣dy which may be seen at one view to be devided by five Lines into four Spaces, equall in Power.
The Painter must suppose one of these four spaces to be lost and the three other to appear, imagining that these three
Spaces which are seen be divided in four Lines equal in a per∣spective Semi-circle, making the chief Light to strike more strong∣ly on the second Line, and in the second space Heightned (which is consequently to be plac'd in the third Line) he shall put as much shaddow as he seeth, and by this means the Figure shall be wonderfully Rays'd, and more then if the Ligbt were plac'd side-long in the first Line, or in the middle on the space between the second and the third, because that makes too much shaddow and this too much Light.
But in Ceilings the Light is taken from the Window so that it cannot be avoided but that the Light will sometimes be receiv'd in the first Line according to the aspect of Lively Bodys either side-long, from above or from below as the Body is tutn'd to the Light.
In the plain Superficies this Rule must be always observ'd that the Light given to Bodys must never be Perpendicular o∣ver their Heads, for it will breed this inconvenience, that the upper parts will always shaddow the lower, as the Eye-brows half the Cheek, the Hair all the Face, &c. except where the Principal of the Picture is in a Scene of Glory above, then the Figures on the Earth may have a Light Perpendicular from the Glory above, as in a Picture of Rubens of St. Roche where the Sudplicants below receive such Light.
That part of the Body is counted next the Light which from the first Pointed extendeth it self farther out on that side then the rest; especially if it be from on high, therefore that Light being the Quicker, causeth the Superficies to receive the Light more strongly viz. that Superficies which is next to us, and that which looketh upwards, both which receive it so much the more strongly by how much the higher they are, because they are nearer the Apointed Light; and this is the Original & Ground of all other Lights which are orderly dispos'd through all Bodys, giving them their Heightning aceordingly to the Direction of that only Light.
Situations and Climates must also be observ'd, they who Inhabit the Temperate Zone the Light casteth their shaddows towards the North: who Inhabit the Hot Zone having a right Spheare, and the Aequinoctial for their Zenith; their shaddows
are under their Feet at noon; because they have the Sun Per∣pendicular to their Body: but they who dwell under the Poles, have their shaddow carryed round about them like a Wheel.
Nevertheless we must generally consider the best Effects of Nature, immitating them by proposing unto us their Examples.
And so must we doe on the Surfaces of High-wayes taking the Light from the East in imitation of the Sun which in that part where it beginneth to rise casteth the shaddows of Bodys towards the West and to other parts according to his Aspects.
We will now lay down a few Precepts necessary to be observ'd and so conclude this Discourse of Chiaro Scuro.
In Light we must consider the Sun in his Luster, as Rising, Meridionall, Setting and according to the Vapours he meets in the Air. Clear Air likewise, through which the Light is spread and is something blewish; and Cloudy Air which is Darker, but leaves more easiness for Objects to be discerned in their true Colours, the Eye not being dazled with too great a Brightness.
We must Consider Lights as Principall falling Perpendicu∣lar (without Interruption) on any Surface or Extremity. Glancing by sliding Diagonally on Elevated Bodys. And Secondary, for things at distance, according to the Thickness of Vapours which Intervene, and offer many incidental opportuni∣tys for giving the more Beauty to the stronger Lights; as likewise loosen the Lighted parts by the opposition of the deep Teints.
If the Design be in the open Air, the Light is extended and diffus'd on the Objects with the greater Tenderness. If in In∣closed Places, it is more consin'd, the Lightnings more strong and Quick.
The Chief Light must be on the Principall Figure of the Group, and must be extended without the Interruption of little shaddows, that the Relievo may stand more boldly out.
All Shaddow must have a Sympathy with the Lights in their Colour as likewise the Reflections with the Bodys Reflecting Arteficial Lights, if very bright, give a quick Heightning, and dark and deeply shortned Shaddows.
Lastly it must be carefully observ'd that betwixt all Lights and Shaddows there must be such Mediums, as may take of all Hardness, and so Arteficially wrought in as may not soul ei∣ther with the other and so take away the Beauty and strength of the Picture.