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.

it nears that line. Then let a darkish narrow strip of
tint meet, and pass along the outline of the cylinder on
the other side of the extreme line of light, after which
gradually fainter tints should follow, treated in a manner
similar to that which has been already described, and
becoming almost imperceptible just before arriving at the
line of light.

This is a very expeditious way of shading a cylinder;
but even to the most experienced colourist, it is not pos-
sible, by the above-described means alone, to impart a
sufficient degree of well-regulated rotundity to the appear-
ance of such an object. Superfluities and deficiencies of
colour will appear here and there. It will be necessary,
therefore, to equalize to some extent, by a species of gross
stippling, the disparities which present themselves. This
is done by spreading a little colour over the parts where
it is deficient, and then passing very lightly over nearly
the whole width of the shade, with the brush supplied
with a very light wash. This process may be repeated to
suit the degree of finish which it is desired to give the
drawing. In the same manner the shading of all curved
surfaces is to be treated.

Recourse is often had to what is called “ washing/’ or
“ sponging/’ in order to impart softness and circularity to
certain forms. Beyond a very limited extent, this is a
most injudicious system. It robs the shade of all the
lightest and most brilliant particles of colour, the natural
position of which is on the surface ; it destroys that
“crisp” freshness, so essential towards the beautiful
appearance of all colouring; and, what is still worse,
spreads a dirty appearance not only over the whole sur-
face of the colouring, but more or less on all the paper
which surrounds it. Sponging should never be adopted,
and if a slight washing with the brush be sometimes
attempted, it should be done very lightly, and, except on
rare occasions, not allowed to pass beyond those parts of
the drawing covered with colour; otherwise that sharp
cleanly appearance which so enhances the effect of a
coloured drawing, will be lost. Let it, then, be remem-
bered, that the less the colour, whether as a shade, shadow,
or tint of any kind, is touched after it has reached the
paper, the better. The system of shading by numerous
tints laid one over the other—a system which almost
universally prevails—is no doubt a very easy, and, there-
fore, advantageous one for the initiation of beginners into
a dexterous use of the brush and the grosser mysteries of
colouring; but no highly effective mechanical drawing
can be produced in this manner. Eschewing, with hardly
an exception, all the methods of colouring in vogue among
water-colour artists, it is certain, nevertheless, that the
most beautiful, effective, and natural water-colour pic-
tures are those which have been produced with the least
effort, or rather elaboration. Look at the works of our
best artists. What are the reasons which render them
so admirable ? Of course we have no intention here of
answering fully this question. One obvious cause for the
favourable impression which they produce we beg to
notice, and that is, the freshness of the colouring. The

colour, in most cases, is put on at once, and then left
undisturbed; there is no meddling with a tint after it
has touched the paper.

The principal shadows are the next parts of the colour-
ing which will now claim our attention. The outline of
any shadow being drawn in pencil, along its inner line—
the line which forms a portion of the figure of the object
whose shadow is to be represented—lay on a strip of the
darkest tint, wide or narrow, according to the width of
the shadow, and then, before it is dry, soften off its outer
edge. This may be repeated as often as the taste of the
colourist may dictate, but the colour should not spread
itself over much more than half the space occupied by the
shadow. These preliminary touches will add to the in-
tensity of the proposed shadow, and neutralize a certain
harshness of appearance inevitable to all shadows made
equally dark throughout. The effect they give to the
drawing is very pleasing, and is, moreover, quite natural,
for, as previously explained, the greatest depth of a shadow
is invariably that part of it immediately contiguous to
the object shadowed forth. An example of this may be
observed in Plate 59, Mill-Gearing. The shadow thrown
on the feather of the wheel, in the cross section, is treated
in the manner described. The whole of the space occu-
pied by the shadow should now be passed over with a
uniform dark tint. To do this skilfully, and especially to
avoid all coarse abruptness in the outline of the shadow,
the brush ought not to be charged with much colour.
When we have treated specially of the colouring of each
metal used in machinery, we shall recur to the manage-
ment of shadows and shading.

The representation of the casting is now to be completed
by laying on the body-colour. This might be done by a
single wash of tint if the appearance of cast-iron were as
light as it is usually depicted ; but its natural colour being,
on the contrary, very opaque and heavy, two and some-
times three washes are necessary, the first tint being rather
darker than those which follow. Each tint should pass
over the shades and shadows where they occur, care being
taken to manoeuvre the brush at such parts very lightly.

The Locomotive Wheel, Plate 60, will serve as a guide
for the depth of tint to be employed for the body-colour
of cast-iron. The shadows, also, on the plan of the wheel
afford very good examples of the intensity which should
characterize those important parts of a coloured drawing.
The exact tone, however, of the tints we are anxious to
indicate, cannot very well be expressed in an engraving,
colour alone can do this ; we, therefore, recommend that
in representing cast-iron in its natural colour, a darker
hue be given to it than is found judicious to introduce in
an engraving.

The most conspicuous fault observable in the generality
of coloured mechanical drawings is a deficiency in the
depth of the tints employed. There appears to exist an
undefinable fear of transferring to paper the naturally
dark appearance of iron; the result is the production of
tame, ineffective representations, which, instead of looking
as they should, like models of iron machines, present mere
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