DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.20658#0174
160 COLOURING-.
all points of the object will represent those points, in such a manner and position as will be pro-
portional and correspondent to their respective positions and distances in the object; so that the
whole image bears an exact resemblance to the whole object.
2. The image will bear the same proportion to the object as their distances from the glass re-
spectively ; that is, if the distance of the image from the lens be one fourth of the distance of
the object from the lens, the picture will be but one quarter of the size of the object; if its di-
stance be one eighth of that of the object, its size will be only one eighth of the magnitude of
the object, &c. consequently the greater the focal distance of the glass the larger will be the
picture of the object; but the less will be the field of view.
3. The image or picture of the object is inverted. This is not the effect of the glass, but of the
crossing of the rays in the hole through which they pass : for a very small hole made in a window-
shutter of a darkened room would have nearly the same effect as a lens: aii external objects
would be seen in an inverted position on a white paper placecf in the room ; those rays coming
from the upper part of the object forming the lower part of the image, and vice vena. All that
the lens does is to render the image more distinct, by conveying every pencil of rays to its proper
focus in the picture.
4. But that which gives life and spirit to this representation, and in which it excels all other
imitations, is that just, display of motion or rest in the several parts of the picture which we see in
those of the object. A more critical idea may be formed of any motion by the picture in a Ca-
mera Obscura, than from observing the motion of the object itself: for instance, a man walking
appears in the picture to have an undulating motion, or to rise up and down every step he takes,
which is exactly the truth in nature; but nothing of the kind can be perceived in viewing the
man himself by the bare eye. And the motions of all animals are more distinctly marked and
apparent, by this observation of their pictures, than can be perceived by the nicest view of the
objects themselves. .
5. The pictures in a Camera Obscura are not only just with regard to their colours, but in their
force and beauty they exceed nature itself. Every piece of imagery has not only all its proper
tints and gradations of colours, but these are always heightened and rendered more intense than
in the object: thus it exceeds the efforts of the greatest masters in painting. This is one of the
principal uses for which it is recommended to the student: and he cannot too frequently study
the beauty and gradations of the tints in this optic picture. The reason why those colours are
heightened above what they are in nature is because all the coloured rays coming from the
object are, in the picture, crowded into a less space.
6. Another very useful end answered by this instrument is to give a just representation of the
chiaro ascuro, or the intensity of light and shadow which, as well as the colourings surpasses the
appearance of nature; because the lights and shadows are concentrated into less space. Every
light and shade is expressed in its proper degree, from the faintest to the most intense, including
a wonderful variety, the consequence of the different situations of the several parts of the object,
and the different angles of reflection. As a just imitation of the chiaro oscuro is a very difficult
part of the art of painting, and is that on which a great part of its success depends, the student
should omit no opportunity, nor despise any aids however artificial that may tend to improve
his knowledge in this branch.
SECTION
all points of the object will represent those points, in such a manner and position as will be pro-
portional and correspondent to their respective positions and distances in the object; so that the
whole image bears an exact resemblance to the whole object.
2. The image will bear the same proportion to the object as their distances from the glass re-
spectively ; that is, if the distance of the image from the lens be one fourth of the distance of
the object from the lens, the picture will be but one quarter of the size of the object; if its di-
stance be one eighth of that of the object, its size will be only one eighth of the magnitude of
the object, &c. consequently the greater the focal distance of the glass the larger will be the
picture of the object; but the less will be the field of view.
3. The image or picture of the object is inverted. This is not the effect of the glass, but of the
crossing of the rays in the hole through which they pass : for a very small hole made in a window-
shutter of a darkened room would have nearly the same effect as a lens: aii external objects
would be seen in an inverted position on a white paper placecf in the room ; those rays coming
from the upper part of the object forming the lower part of the image, and vice vena. All that
the lens does is to render the image more distinct, by conveying every pencil of rays to its proper
focus in the picture.
4. But that which gives life and spirit to this representation, and in which it excels all other
imitations, is that just, display of motion or rest in the several parts of the picture which we see in
those of the object. A more critical idea may be formed of any motion by the picture in a Ca-
mera Obscura, than from observing the motion of the object itself: for instance, a man walking
appears in the picture to have an undulating motion, or to rise up and down every step he takes,
which is exactly the truth in nature; but nothing of the kind can be perceived in viewing the
man himself by the bare eye. And the motions of all animals are more distinctly marked and
apparent, by this observation of their pictures, than can be perceived by the nicest view of the
objects themselves. .
5. The pictures in a Camera Obscura are not only just with regard to their colours, but in their
force and beauty they exceed nature itself. Every piece of imagery has not only all its proper
tints and gradations of colours, but these are always heightened and rendered more intense than
in the object: thus it exceeds the efforts of the greatest masters in painting. This is one of the
principal uses for which it is recommended to the student: and he cannot too frequently study
the beauty and gradations of the tints in this optic picture. The reason why those colours are
heightened above what they are in nature is because all the coloured rays coming from the
object are, in the picture, crowded into a less space.
6. Another very useful end answered by this instrument is to give a just representation of the
chiaro ascuro, or the intensity of light and shadow which, as well as the colourings surpasses the
appearance of nature; because the lights and shadows are concentrated into less space. Every
light and shade is expressed in its proper degree, from the faintest to the most intense, including
a wonderful variety, the consequence of the different situations of the several parts of the object,
and the different angles of reflection. As a just imitation of the chiaro oscuro is a very difficult
part of the art of painting, and is that on which a great part of its success depends, the student
should omit no opportunity, nor despise any aids however artificial that may tend to improve
his knowledge in this branch.
SECTION