TIN-PLATE DECORATION
Suitable Designs--A Variety of Effects--Gold Lacquer--
Super-position of Colours--Embossed Effects--Embossing
Plates--Lacquers.
It is usually and rightly supposed that the most effective results in
Tin-plate Decoration are produced from designs which are lithographed
for that specific purpose.
Designs which are specially arranged for Paper Printing can be used so
long as the effect produced by the transposition from right to left does
not affect its application, or render the same impossible. This, of
course, applies more particularly to designs in which lettering appears,
but at the same time it may affect designs of an essentially pictorial
character in an equally important manner; for it must be remembered that
a drawing for Tin-plate Printing must appear on the lithographic stone
exactly as it is impressed on the metal, and not, as in Paper Printing,
reversed from right to left. This naturally simplifies the drawing on
stone, and to some extent enables the draughtsman to dispense with the
reversing mirror when copying.
The primary object of this short chapter will be to point out some of
the characteristic features of Tin-plate Decoration, so that such
methods as are usually adopted by the artist and the printer may be
modified or amplified to meet any peculiar requirements of work in hand.
A greater variety of effects can be attained on the polished metal
plate than it is at all possible to produce on paper.
A gold effect, the result of lacquer printing, is especially striking.
In a similar manner an excellent translucent lustre can be imparted to
almost any colour by taking away the white opaque ground, and thereby
producing a peculiar semi-transparency which is both pleasing and
effective. Lacquer printed over _white_ produces a _buff_ colour, which
can be used as a second yellow or to form the base of a flesh. The
colour of the lacquer is softer and less obtrusive when printed under
instead of above the white. The super-position of colour generally, as
described in Chap. XII. page 70, is peculiar to tin-plate printing, and
suggests the advisability, if not the necessity, of a special design.
The advantages of such super-position are obvious and substantial. Under
ordinary commercial conditions it is almost impossible in tin printing
to obtain the same intensity of tones in the printed colours as in paper
printing. Some such strengthener as the super-position of suitable
colours is therefore necessary. The work of the lithographic draughtsman
is in this respect of a somewhat unusual character; but a little
intelligent consideration will render its execution on these lines
comparatively easy and satisfactory.
As already stated, yellows can be accentuated by a super-position of
lacquer, and in the same manner blues and greys add intensity to black.
Red can be strengthened by a foundation of lacquer, also flesh and
yellow, either singly or in combination. The drawing of lacquer and
white formes should receive the most careful attention. They should fit
each other accurately, even to the most minute details; for the
slightest overlapping will be revealed by the presence of a very
assertive buff colour, while any deficiency in combination will leave a
not less striking margin of bright tin exposed.
In some instances it might be an advantage to transfer one forme from
_black_ to _white_ to produce the opposite colour, and thus ensure
perfect register.
In decorative designs particularly, tin-plate printing suggests almost
unlimited possibilities for brilliant effects, and in this respect it
offers fair latitude for individual originality and manipulative skill.
In the production of show tablets especially, considerable attention has
been given to embossing, in order to suggest and represent relief.
Though not actually produced by the artist, this is in effect part of
the scheme or plan of his design, and will consequently influence his
work to some extent. For simple ornamentation only, metal embossing
presents little that is new or novel; but for the production of relief
effects in the pictorial elements of a design its application becomes a
more important and influential matter. By its aid a flat and otherwise
uninteresting subject can be made attractive and vigorous, and for
general purposes of effective display its value will be considerably
enhanced and its assertive character emphasised.
Without entering too minutely into matters which affect the lithographic
printer in an indirect fashion only, it will yet be useful to him to
know how an embossing die is produced which registers accurately with
the design to be operated on. A black impression of the outline forme of
the design is made on transfer paper similar to that described in Chap.
XII. page 68, and re-transferred, by pressure only, to another sheet of
the same paper. The re-transfer is to be the impression required, and
this in its turn is re-transferred again to a prepared brass plate. The
only preparation necessary is the levelling and planing of the plate,
and, if desired, it can be coated with a thin layer of white paint or
enamel. This white ground makes the work easier, by rendering the
impression more distinct. With such a guide as this the cutting or
engraving is a comparatively simple matter.
The engraved plate is placed in a casting box, and a stereo-metal
casting is made from it. A little trimming may be necessary for the
completion of these two tools, and they will require to be suitably
mounted, so that they may be accurately adjusted in the embossing press.
Metal embossing has certain limitations which must be recognised as an
essential condition of its effective application.
The plates vary considerably in texture and temper, and the depth and
character of relief will, to some extent at least, be controlled by the
quality of the metal. Sharp lines and abrupt terminations impose a
strain under which many plates split, therefore such features ought to
be avoided. Easy, rounded lines, rather than those of the straight
furrow description, produce the best results and give least trouble
during operations. Where abrupt terminations are quite unavoidable the
design should, if possible, be so arranged as to evade the
super-position of colour over these parts.
Lacquer, if properly mixed and applied, is probably the toughest pigment
used by the tin printer, and is generally suitable for embossed work. It
prints an exceedingly thin layer or film on the face of the metal, which
under average conditions rarely interferes with the working of the
embossing tool.