Armengaud, Jacques Eugène; Leblanc, César Nicolas   [Hrsg.]; Armengaud, Jacques Eugène   [Hrsg.]; Armengaud, Charles   [Hrsg.]
The engineer and machinist's drawing-book: a complete course of instruction for the practical engineer: comprising linear drawing - projections - eccentric curves - the various forms of gearing - reciprocating machinery - sketching and drawing from the machine - projection of shadows - tinting and colouring - and perspective. Illustrated by numerous engravings on wood and steel. Including select details, and complete machines. Forming a progressive series of lessons in drawing, and examples of approved construction — Glasgow, 1855

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ENGINEER AND MACHINIST’S DRAWING-BOOK.

composed, may be observed on Plates 37 to 43; and with,
more minute effect on Plates 61 to 63, showing a Double
Blowing Engine, by James Gray & Co. Every figure
looks complete without elaboration, and is clearly de-
lineated without degenerating into the bareness of a mere
skeleton. Outlines and forms are at once apprehended,
and every member of the machine is adjusted without
hesitation to its proper place.

In such drawings shading only is allowed, and, there-
fore, but slight scope is permitted for imparting effects;
and it is advisable to follow a direction previously given,
viz.: to modify the colour on every part according to its
distance from the eye. This difference in the tone of the
shading is fitly expressed in Plates 37 and 39, by the
shade on the fly wheel, as compared with that on the
more prominent members of the machine. It may be as
well also, for the purpose of maintaining harmony in the
colouring, and of equalizing its appearance, to colour less
darkly large shades than small ones, although they may
be situated at an equal distance from the eye. No very
dark shading is permissible on this species of drawing;
indeed the tint should be very considerably lighter than
on finished coloured drawings. Besides presenting too
violent a contrast between the parts coloured and those
without any colour at all, dark shading would produce, in
some measure, the indistinctness which is objectionable in
completely tinted drawings.

SECTION III.

Finished Colouring.

The two preceding sections have been almost wholly de-
voted to the exposition of some general rules for shading,
applicable alike to the surfaces of all bodies, and irrespec-
tively of any particular colours; to directions for repre-
senting shadows effectively ; and to some suggestions for
modifying shades and shadows, so as to render them con-
formable to the peculiarities in the aspects which bodies
present, and to the different distances which they may
occupy in reference to the eye. The methods of shading,
which have been therein described, are simple and easily
performed, and are adapted for indicating the configura-
tion of any object, no matter of what material it may be
composed.

In the present section, machinery will claim our exclu-
sive consideration, and as we have copiously treated of
shades and shadows, our principal attention will now be
directed to the body colours best adapted for depicting
the various materials employed in the manufacture of
machinery; to their composition and mixture; to the
best way of laying them on; and to the various effects to
which they may be made subservient.

The shades and shadows of a machine, however, beino’
inseparably associated with its body colour, will, neces-
sarily, claim some further exposition ; indeed, we propose
in this section to develope a method of colouring machinery

which is not generally known, but which we presume to
be more effective than any hitherto practised, though
more difficult in its execution. We shall have occasion,
therefore, to continue the subject of shades and shadows,
and to show how strikingly, by judicious management,
these parts of the colouring may be made to enhance the
effective appearance of a mechanical drawing.

At the outset we beg to advise the learner not to at-
tempt the method of shading we propose to explain, until
he is well versed in those simpler methods which we have
previously described.

The colouring of drawings representing machinery re-
quires a special study, the process of its development being,
in many essentials, very different from that pursued in
the artistic expression of other objects. The materials of
which machinery is constructed, and the purposes to which
such constructions are destined, seem to imply “mechani-
cal” treatment in the methods employed to represent them
on paper. No recourse can be had to indefinite dashes of
the paint brush to produce “effects ” Such “inspirations”
must be left to historical, landscape, or architectural
artists. No pretty but imaginary “dimples” here and
there can be allowed in the portraits of machinery; on
the contrary, the mechanical student should never deviate
from the “right line” of precision and exactitude; few
and slight should be the demands made upon the ima-
gination. We insist particularly upon this unimaginative
peculiarity in mechanical colouring, because its recognition
is a necessary mental preparation for entering upon a con-
sideration of the style of tinting which we are about to
describe. Ordinary systems of colouring are only appli-
cable to a very limited extent in the representation of
machinery. We never knew an artist, of any denomina-
tion whatever, who could colour a mechanical drawing
with that “hard,” sharp, and clear effect, so essential to
the accurate portraiture of machinery.

Premising a few observations on the primary object
aimed at by the art of painting, and especially the result
sought to be effected by colouring drawings of machinery,
we shall proceed to detail minutely the colours best
adapted for expressing the natural appearance of those
metals generally used to form the parts of a machine;
their relative proportions when in combination ; and the
manner in which each tint is to be applied.

The most ambitious aim desired to be achieved by
means of a painting, is to delude the spectator into a belief
that he actually sees the subject represented. The degree
of an artist’s ability, therefore, should be measured by
his power of identifying his production with the objects
he desires to present to the eye. On the other hand, if
an artist, from respectful deference to the antique style
of painting, perseveringly endeavour to represent in a
picture, say of the “ Crucifixion,” a murky and tempestu-
ous ocean occupying the legitimate locality of clouds, the
beholder might, no doubt, be very much awe-stricken, but
he could hardly realize the power of respiration in such a
dense medium. So with regard to machine representa-
tion : suppose a powerful stationary engine to be coloured
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