DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.2086#0026
18
LANDSCAPE PAINTING.
Colour of the Wafer.
Accidental Colour, or Colour
of the Ocular Spectra.
RED .
ORANGE
YELLOW
GREEN
BLUE .
BLUISH GREEN.
BLUE.
INDIGO.
VIOLET REDDISH.
ORANGE RED.
Accidental Colour, or Colour
Colour of the « afer. op Tm. 0cuiar SpECTBA.
INDIGO..... ORANGE YELLOW.
VIOLET..... YELLOW GREEN.
BLACK..... WHITE.
WHITE..... BLACK.
"In order to find the accidental colour of any colour in the spectrum, take half
the length of the spectrum in a pair of compasses, and setting one foot in the colour
whose accidental colour is required, the other will fall upon the accidental colour.
Hence the law of accidental colours derived from observation may he thus stated.—
The accidental colour of any colour, in a prismatic spectrum, is that colour which in
the same spectrum is distant from the first colour half the length of the spectrum ;
or if we arrange all the colours of any prismatic spectrum in a circle, in their due
proportions, the accidental colour of any particular colour will he the colour exactly
opposite that particular colour. Hence the two colours have been called opposite
colours.*
" If the primitive colour, or that which impresses the eye, is reduced to the same
degree of intensity as the accidental colour, we shall find that the one is the comple-
ment of the other, or what the other wants to make it white light; that is, the
primitive and the accidental colours will, when reduced to the same degree of inten-
sity which they have in the spectrum, and when mixed together, make white light.
On this account accidental colours have been called complimentary colours.
" With the aid of these facts the theory of accidental colours will be readily
understood. When the eye has been for some time fixed on the red wafer, the part
of the retina occupied by the red image is strongly excited, or, as it were, deadened
by its continued action. The sensibility to red light will therefore be diminished,
and consequently when the eye is turned from the red wafer to the white paper, the
deadened portion of the retina will be insensible to the red rays which form part of
the white light from the paper, and consequently will see the paper of that colour
which arises from all the rays in the white light of the paper but the red ; that is of
bluish green colour, which is therefore the true complementary colour of the red
wafer. When a black wafer is placed on a white ground, the circular portion of the
retina on which the black image falls, in place of being deadened, is protected, as it
were, by the absence of light, while all the surrounding parts of the retina, being
excited by the white light of the paper, will be deadened by its continued action.
* It has been already observed, that the proportion of the colours in the spectrum vary even by the same
kind of light, when prisms are used of different refracting substances. To verify the above experiments it
will be necessary to use a prism of flint glass.
LANDSCAPE PAINTING.
Colour of the Wafer.
Accidental Colour, or Colour
of the Ocular Spectra.
RED .
ORANGE
YELLOW
GREEN
BLUE .
BLUISH GREEN.
BLUE.
INDIGO.
VIOLET REDDISH.
ORANGE RED.
Accidental Colour, or Colour
Colour of the « afer. op Tm. 0cuiar SpECTBA.
INDIGO..... ORANGE YELLOW.
VIOLET..... YELLOW GREEN.
BLACK..... WHITE.
WHITE..... BLACK.
"In order to find the accidental colour of any colour in the spectrum, take half
the length of the spectrum in a pair of compasses, and setting one foot in the colour
whose accidental colour is required, the other will fall upon the accidental colour.
Hence the law of accidental colours derived from observation may he thus stated.—
The accidental colour of any colour, in a prismatic spectrum, is that colour which in
the same spectrum is distant from the first colour half the length of the spectrum ;
or if we arrange all the colours of any prismatic spectrum in a circle, in their due
proportions, the accidental colour of any particular colour will he the colour exactly
opposite that particular colour. Hence the two colours have been called opposite
colours.*
" If the primitive colour, or that which impresses the eye, is reduced to the same
degree of intensity as the accidental colour, we shall find that the one is the comple-
ment of the other, or what the other wants to make it white light; that is, the
primitive and the accidental colours will, when reduced to the same degree of inten-
sity which they have in the spectrum, and when mixed together, make white light.
On this account accidental colours have been called complimentary colours.
" With the aid of these facts the theory of accidental colours will be readily
understood. When the eye has been for some time fixed on the red wafer, the part
of the retina occupied by the red image is strongly excited, or, as it were, deadened
by its continued action. The sensibility to red light will therefore be diminished,
and consequently when the eye is turned from the red wafer to the white paper, the
deadened portion of the retina will be insensible to the red rays which form part of
the white light from the paper, and consequently will see the paper of that colour
which arises from all the rays in the white light of the paper but the red ; that is of
bluish green colour, which is therefore the true complementary colour of the red
wafer. When a black wafer is placed on a white ground, the circular portion of the
retina on which the black image falls, in place of being deadened, is protected, as it
were, by the absence of light, while all the surrounding parts of the retina, being
excited by the white light of the paper, will be deadened by its continued action.
* It has been already observed, that the proportion of the colours in the spectrum vary even by the same
kind of light, when prisms are used of different refracting substances. To verify the above experiments it
will be necessary to use a prism of flint glass.