DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.1211#0010
ON
LIGHT AND SHADOW.
W HEN you draw from nature, place yourself with your left band to the
light, which, if you can choose, is best from the north, as being steadiest;
but if the window happen to have another aspect, it will be convenient to
place an oiled sash, or white blind, before it, that the sun's light may be
spread equally and Avithout sensible alteration : the light should also come
from such an attitude, as that the shadow of the object you draw from may
in length be equal to its height, as in fig. 1, plate 2, supposing the light to
fall upon it from A.
A ball is chosen, for an example, to illustrate the subject, in order to
shew that the idea is founded on a fixed law of nature; and that the effect
of light on the most diminutive sized ball (when the light is proportioned
to the size of it) is the same as on the ball of the earth when enlightened by
the sun ; which, it must be observed, can only enlighten one part of it
strongly at a time: the rotundity of the earth may be considered as a proof of
this. It is difficult to say exactly what space or portion of the globe is equally
enlightened at one and the same time. I should suppose about one-eighth
of its circumference; at least about that space when delineated upon paper;
with the following proportion of shade, will produce the convex appearance ;
and from which I infer that every single object, or group of objects, let their
LIGHT AND SHADOW.
W HEN you draw from nature, place yourself with your left band to the
light, which, if you can choose, is best from the north, as being steadiest;
but if the window happen to have another aspect, it will be convenient to
place an oiled sash, or white blind, before it, that the sun's light may be
spread equally and Avithout sensible alteration : the light should also come
from such an attitude, as that the shadow of the object you draw from may
in length be equal to its height, as in fig. 1, plate 2, supposing the light to
fall upon it from A.
A ball is chosen, for an example, to illustrate the subject, in order to
shew that the idea is founded on a fixed law of nature; and that the effect
of light on the most diminutive sized ball (when the light is proportioned
to the size of it) is the same as on the ball of the earth when enlightened by
the sun ; which, it must be observed, can only enlighten one part of it
strongly at a time: the rotundity of the earth may be considered as a proof of
this. It is difficult to say exactly what space or portion of the globe is equally
enlightened at one and the same time. I should suppose about one-eighth
of its circumference; at least about that space when delineated upon paper;
with the following proportion of shade, will produce the convex appearance ;
and from which I infer that every single object, or group of objects, let their