WORK WITH THE BLOCKING PRESS.
We make a distinction between gold tooling and blind tooling. The latter
is simply an impression on the leather or other material without the use
of gold, whilst the other is an impression upon a specially prepared
leather or other surface, using gold leaf.
Skill in blocking depends first of all upon a tasteful and suitable
selection and arrangement of the engraved blocks and letters necessary
for the decoration and inscription.
The blocks, &c., are to be had ready made from the engravers in properly
arranged sets; but still it is essential that the finisher should
possess certain artistic taste and feeling, especially in making up the
lettering. It must be borne in mind that in an inscription or title the
principal part (word or line) must be distinguished by larger or heavier
type; furthermore, two lines of equal length must never appear in an
inscription. Short words (the, and, for, &c.) worked into an inscription
as separate lines add considerably to its appearance. See pp. 148 to 153
for what is said on the arrangement of the title in hand lettering. The
same applies to the arrangement of all lettering.
The blocks and letters are always fixed to the upper part of the
press--the platen.
To enable alterations to be made quickly or to secure pieces which may
have slipped, there is a draw-out plate made in all modern blocking
presses. The engraved blocks are not affixed to this plate with glue but
with cobblers' wax. The following is a practical way of managing the
ornamental blocks: On a thin but very strong board about the size of the
article to be blocked, the blocks are arranged with the backs uppermost,
the engraved face being next to the board. This board is fixed with wax
exactly in the centre of the lower part of the press--the table. By
"exactly in the centre" it is to be understood that the centre of the
various blocks brought together lies on or near the centre of the
draw-out plate. If there are more and heavier blocks fixed to the upper
than to the lower side of the plate, the latter must be lowered a
little--in a word, the plate must be so adjusted that all parts receive
equal pressure. It is only by making a few trials that one can learn
exactly what is right.
The press should be warmed by this time, and it is well to slide in the
table with the blocks adjusted upon it, and to let it remain under light
pressure until plate and table are warmed throughout and no trace of
moisture may be seen on either. Now put a little wax on each block, lay
over them a piece of stout wrapping paper, cardboard, or similar stuff,
push in and press gently; the wrapper also may be waxed. After about
five minutes, open the press to see whether all parts have stuck. Until
this takes place the press must remain closed. If, however, all pieces
are sticking fast, draw out the table and examine the imprint of each
particular part to see whether the pressure is equal; if this is not so,
it remains to be seen whether such inequality is due to a faulty fixing
of the plate and, if necessary, to rectify it; otherwise, pieces of
paper must be made up into a suitable packing and laid upon the back of
the blocks until all inequalities are removed and an even impression is
obtained.
This done, the back of the set-up blocks, or the wrappers affixed
thereto, is waxed at as many places as required, or rather as far as
the set-up blocks extend, the plate pushed in, and the press closed
until the set-up blocks adhere to the upper plate. The lighter this
first impression is made, the easier it will be to detect any inequality
on the table (or matrix) and to set it right by backing up with paper.
Fig. 64--Blocking press.
Before proceeding further, a few words must be said about the
construction of our modern blocking presses. For modern blocking we use
knee-lever presses, whilst balances are now no longer used.
On the upper part there is a sliding plate--the so-called platen--which
draws out on prismatic rails.
A second plate works on hinges at the side of the sliding (or draw-out)
plate and can be pulled out to the left. This plate is used principally
for colour blocking--the other plate for gold.
Blocking can be done in gold and colour immediately after each other,
and if the plate is in duplicate, four impressions can be made in
succession without having to take off and change the plate.
In the upper plate there are round borings for the gas burners or hot
irons used for heating the press; the latter are out of date and do not
produce a steady temperature.
It now remains to insert the article to be blocked in the press so that
it will be blocked exactly on the spot required.
There are several ways of attaining this object, which are adopted
according to the kind of work in hand. The surest way is to mark the
place by pins.
Two large drawing pins are pasted upon pieces of cardboard, a second
piece of board is placed over each one so that the head is embedded
between the two pieces but leaving the points free. The gauges thus made
are fixed with wax at convenient places, best on the middle line above
and below the table but in such a way that they themselves are not
touched by the plate. To prevent their falling off, a larger piece of
cloth is pasted over them, always leaving the points visible. The surest
preventive against falling off is to have screw-on gauges. A strip of
metal having a slit in the middle can be screwed tightly to the table by
means of a screw passed through the slit. At the end a steel point about
1/2 cm. long is riveted on. With this gauge the points can be adjusted
to any position on the table as required.
All work not turned-in which requires repeat blocking, and all such as
requires blocking in more than one colour, is "pinned on." On the other
hand, covers which are finished after being once blocked on back or side
which require no second impression may be adjusted with the angle gauge
or blocks. Many make use of both at the same time. Such covers then have
been turned in all round when being worked, whilst "pinning on" requires
that the covers should not have been turned in.
The practical bookbinder who has to deal with turned-in covers
frequently gets over the difficulty by making two incisions about 2 cm.
apart with the knife upon the turned-in edge at the place where it
should be pinned on, and opening out the material at the incisions, thus
making a loose margin for pinning on.
For pinning on covers as well as backs, a template is cut from wrappers
or thin board, which is adjusted on the cover and the register holes
made with an awl. When pinning-on has to be done for blocking which has
to be repeated very many times, the register points are strengthened
behind with stiff paper to prevent them from breaking or tearing away
and thus becoming inaccurate.
Fig. 65--Appliances used in blocking backs.
To enable the most various widths of backs to be quickly inserted and to
supply a substitute for the thick layers of cardboard packing which make
a fine impression impossible, a special contrivance with metal pads has
been made. This is shown in the sketch herewith.
Mention has already been made of the table (or matrix). This is a bed of
stout boards which is intended to serve the double purpose of saving the
blocks when blocking thin articles (backs of covers, &c.) and also for
strengthening and equalising the resistance from below when working on
heavier articles. Faults arising during working, such as insufficient
adhesion of the gold (and an increased pressure) may be set right by
pasting on pieces of paper to the matrix or table.
The matrices consist of strong but thin material; the best is wrappers
or the thinnest board. After use they are kept for subsequent
repetitions of the same or for other work.
The lettering must always be set up fresh for each job, whilst the
ornamental pieces may be arranged on the tables or matrices at hand
after the existing original impression.
Setting the type is a special art and calls for considerable taste and
skill; the letters very easily slip out of the type-holder, especially
where very small type is used, unless special precautions are taken to
prevent this. Here we will pass over the most important point in the
arrangement of the types and refer to the paragraph dealing with
"Lettering" under "Hand-tooling"; what holds good there always holds
good here.
Lettering is always set upon special pieces of board and afterwards
encased in a type-holder, as it demands much more attention and
subsequent correction. These boards should likewise be wrappers of the
same thickness as those used at the same time for the ornaments. For
fixing, cobblers' wax is likewise used. The favourite method frequently
adopted of using glue coated with paste is not to be recommended,
because the letters do not admit of proper setting upon this gelatinous
mass. Not only do the lines of letters require to be kept right by means
of a strip of metal or metal line, they must be carefully adjusted after
taking a light impression, especially when using a very small type. The
first pull must be under so light a pressure that on a soft paper
everything is distinctly visible. The lines are arranged from this
proof, whilst each single letter is carefully checked. Where letters do
not show up properly they must be backed up with paper of suitable
thickness on the board until all unevenness disappears. The lighter the
pressure applied the easier it will be to make corrections. Letters
heavily pressed at the outset can seldom be properly rectified
afterwards.
In large editions it does happen, in spite of all precautions, that
single letters work loose and fall out; this may damage parts of the
plate as well as valuable covers, and one therefore tries to guard
against it. Some take narrow strips of cloth and paste one round each
line of type, others pour liquid glue between the lines which, when
thoroughly dry and hard, is a very sure means of preventing the falling
out of any piece of type.
When everything is in order, the type is likewise inserted; various
parts of the back of the board are well waxed and the table is then
pushed in and the press closed tight. It remains closed until all parts
are thoroughly dry, for it is only then that we may feel assured that no
parts can fall out. The drying may be hastened by opening the press
about a quarter of an hour later and drawing out the plate, likewise the
table, and now allowing plate and table to dry by exposure. If any parts
of the plate should lift, wax must again be applied and once more
pressed.
When the plates and press are got into working order, and the backs or
covers have received their register marks by means of the template, the
blocking may be commenced. The table is drawn out, a piece of work
pushed in to the register, and the press closed. It is necessary that
the press should have been previously regulated to the thickness of the
article being blocked, and to begin with a light pressure at first, as
heavier pressure can be applied afterwards if required. Cloth requires
sharper pressure than leather. Large heavy covers are always blocked
with the press quite closed, whilst small things like single titles, hat
linings, ties, &c., are finished with only a short pull of the lever.
The correct regulation of the pressure rests with the worker.
We distinguish between blocking in blind, gold, colour, and relief.
Blocking in blind, both on leather and cloth, should not be attempted
upon articles which have become very dry. A good plan is to store them
in a cellar the night before and to bring out only as many as can be
finished in the next half-hour's work. Blocking in blind can only be
done on matt or grained material, as its effect is nil upon a smooth
polished surface.
The finish can be considerably heightened in special cases by going over
the impression with a brush and white of egg after the first blocking
and then again pressing under less heat. Calf leather, and undressed
calf in particular, receives its splendid brown colour by being
previously damped with boiled or distilled water to which a little
spirit has been added. The impression on a damped ground is first made
somewhat warmer and afterwards repeated when the press has cooled a
little, occasionally wiping the blocks with a waxed cloth. The
impression must in all cases be even in colour and have a high finish;
if this is not so, the lighter places must be once more damped with a
small brush and again impressed.
Articles to be blocked in gold must be prepared with some substance to
which the gold will adhere. The finisher uses a fluid or dry adhesive
according to the material he is working upon. Of liquid sizes, diluted
white of egg or, in some cases, dissolved gelatine or blood serum is
used almost exclusively. These liquids, which are applied with a sponge
or, for fine work, with a brush, are called the "ground" or "sizing." Of
dry adhesives, we know only the gilding powder, which consists of resin
with now and then an addition of dried white of egg. The other powders
used by the finisher are rice flour or potato flour; these are not used
as adhesives but to prevent the gold sticking at places where it is not
wanted.
Leather and cloth are sized with white of egg; silk and other woven
materials are finished without special sizing, and also surfaced papers
and cardboard goods, as they are treated with finishers' powder, a wet
preparation being unsuitable.
Size for blocking is thinner than for hand finishing, and when it has to
be washed over the whole of a cloth cover it is still further diluted.
Glair for brushing over an impression consists of one part white of egg
and one part vinegar; to every 1/2 litre 1 g. of powdered borax is
added, the whole beaten to a froth and filtered. For coating-over, take
one part white of egg, two parts water, and to every 1/2 litre add 10
drops of glycerine and 1 g. borax. If a larger quantity of glair is
required for coating over, it may be thinned with water or vinegar; but
size made with vinegar must not be applied to fancy coloured cloths.
Gilding powder may be yellow or white, the latter kind is rougher and is
suitable for silk stuffs and also where blocking has to be done over
colour on cloth. Yellow powder is softer and is apt to clog the finer
cut tools; it is more suitable for the preparation of paper _de luxe_,
for blocking surface and chromo papers, and for photo cases.
Gilding powder is sprinkled by means of a box which has a double layer
of fine gauze instead of a bottom. By tapping upon the box a fine shower
of powder is dusted on to the surface to be gilded.
Glair is made in the workshop; the powder is bought ready prepared--to
make it would take too much time.
For blocking in alloyed metals, gelatine size is used, as it is a
powerful adhesive. A tablet of gelatine is soaked in 1/4 litre of water
overnight and next morning is dissolved in the bath. Gelatine is used to
cover the whole surfaces and is laid on when lukewarm. Blood serum
serves the same purpose. Ox blood is allowed to coagulate, and the
hardened mass thus produced is placed over a cloth strainer, or hair
sieve, and the liquid albumen allowed to drain from it; the process is
hastened by cutting the caked blood into small pieces. Only the clear
liquid which is strained off is to be used--a pinch of borax will make
it keep longer.
For finishing bindings, real gold-leaf--orange tint--is used almost
exclusively, the cheaper green gold being used only for sample cases and
school books. Alloyed metal and aluminium (this is now commonly used
instead of the quickly oxydizing silver) are used almost solely in the
manufacture of papers _de luxe_ and for placards.
Pure gold-leaf is always laid on the sized cover after the surface to be
blocked has been lightly gone over with a ball of oiled cotton wool, or
a slightly greased rag. This must never be done to such a degree as to
cause grease spots. Calf must not be thus treated with grease, but if
the gold is not likely to stick at certain places, the first impression
may be picked out with a brush slightly oiled so as to make the leaf
adhere. Dark polished calf will, however, stand a little oil.
Fine leathers are first stamped and the impression is gone over with a
brush, then the gold is laid on and again impressed. The gold is lifted
from the cushion with a gilder's tip or a pad of cotton wool and
transferred to the cover. The gilder's tips consist of square pieces of
cardboard a little smaller than the piece of gold to be used, to the
under side of which is pasted a piece of cloth. A handle of cardboard or
a button is pasted on top for convenience of holding.
Draw this tip lightly over the hair, press it on the gold, which will
lightly adhere to it, and then transfer the gold to the surface to be
stamped, where it is pressed down with cotton wool, which should be
surgical wool, as that kind is free from knots. Many prefer a tuft of
cotton wool rolled into a handy size, this is likewise drawn over the
hair, and the rest done as before.
When gilding powder is used, the gold must not be laid on with the pad.
The gold must be placed on the powder by hand only, a task calling for
considerable adroitness. The gold is taken up with the gold-knife, aided
by a moistened finger-tip taking a corner, passed over the surface with
the knife, brought to the required position with the hanging corner, and
now the knife is taken away flat sideways. The gold must lie quite even
on the powdered surface. Any subsequent shifting of the gold is entirely
out of the question, because the layer of powder would be disturbed and
might not hold in places.
To know exactly what degree of heat should be applied requires special
study, and the pity is that fixed rules cannot be given--one day a black
morocco goat-skin may stand a great heat, whilst on another day the same
heat applied to similar stuff might burn it up. Cloth is always the
same, calf leather papers, skytogen, &c., are much more difficult. On
the whole, the following rules may be observed:--
Cloth white of egg (or glair) medium heat
Sheep-skin " slight heat
Goat-skin " medium heat
Morocco " medium heat
Silk white gilding powder short hot pressure
Surface
papers and
cardboards yellow " " short medium pressure
Calf glair hot (light leathers
somewhat less heat)
Varnished paper little heat
The latter contains sufficient adhesive matter in the colour without
using any other size, even for alloyed gold, but the covers must,
however, be slightly moist. For this purpose they are left overnight in
a damp cellar or placed between slightly damped boards.
We have already spoken of the matrix. Where silk or other thin woven
materials are to be blocked, a firm hard board must be laid on the table
and frequently changed, otherwise the impression will be defective. For
ribbons for wreaths, &c., a suitable piece of paper which had been
damped some time before should be laid underneath.
Although relief blocking upon bindings seems to be out of favour, there
are numerous styles of imitation relief practised nowadays, especially
in imitation of cut leather or wrought metal. This work necessitates the
matrix or table being prepared with great care, as it must be the
counterpart of the plate. For this purpose an impression is first made
upon a stout cardboard, which is fixed firmly enough on the bed to
prevent its shifting, the block being affixed to the platen. Upon this
first cardboard are laid the raised parts according to the height
required, likewise cut out of stout cardboard, continuing to place a
layer upon the other until a true negative of the block is obtained.
Small and slightly raised ornamentation is not specially underlaid,
using instead a piece of stout board well smeared with cobblers' wax,
which, after standing awhile under the plate in the closed press, will
make a very exact and firm base. Matrices made up of several layers of
cardboard pasted on top of each other are also, when finished, covered
with a piece of pasted packing paper and then pressed. This leaf
prevents single pieces from working loose and sticking to the block.
For relief stamping, leather or cloth is stretched upon thin wrappers.
The guide points must be made a little further apart on account of the
material shrinking slightly under relief stamping.
Colour blocking, which has gained such unexpected popularity, gives the
finisher no little trouble. As blind blocking is done by the press, so
also may colour blocking be done if the blocks are coloured with the
brilliant colours specially prepared for printing. A colour roller, made
by moulding English roller composition on a wooden pin, is used for
colouring the blocks. The worker himself may cast these rollers in a
well-greased mould. The roller composition is dissolved in water, and
after being poured into the mould is allowed to stand a few hours to
cool. The colour blocker keeps about three rollers ready, of which one
is used for light colours, another for middle tones, and the third
solely for black. The rollers are either fixed in a fork with two
handles or an axle goes through the wooden pin which is bound in leather
at each end wherein the axle revolves in the hollow of the hand.
Fig. 66--Colour roller.
The rollers spread the colour upon a stone of suitable size. The colour
should be laid on the rollers--not on the stone--not too thickly, and
then evenly distributed on the stone by bringing the roller over it
backwards and forwards. Both stone and roller must always be cleaned
after use; perfect cleanliness must be carefully observed throughout.
The stone is cleaned with petroleum, the remaining colour is removed
from the roller by passing it several times over a sheet of glass,
rubbing it down with petroleum before again using it so as to remove any
particle of dust adhering.
In order that the colours may appear as bright as possible, a little
varnish is added to them, which in every case must be of a kind to suit
the particular colour. Dammar varnish is suitable for light colours, and
for darker colours amber varnish. Where great brilliancy is required,
Venetian turpentine is added; but this lengthens the time required for
drying if a little too much is added.
In every case, however, a little siccative must be added to every
colour; a few drops materially quicken the drying.
Colour blocking can only be done when the blocks have been secured to
the plate, as this must be opened each time it is coloured.
The simplest colour-printing is where one colour appears between the
impression in gold, and in this case it is generally done by first
making the impression in gold and then in colour.
In more complex work several colours are to be used; at the present time
the work is frequently produced requiring colours side by side and
superimposed, together with gold, bronze, and aluminium.
The process is in each case as follows: From the block supplied by the
engraver an impression is made which forms a matrix. It is best to
select a piece of board exactly the size of the covers to be printed and
at the two places to be taken by the guide points pieces of vellum are
firmly pasted, being already pierced for the guide points, these vellum
additions being further secured by pasting over them a strip of paper or
cloth. For every block to be used a similar board with its vellum
additions is prepared. Upon the ground of this first matrix the other
auxiliary matrices are likewise first impressed with the block--all of
them black, of course, so that it would be possible at any time to fit
in the blocks.
Every new block for colour printing is pressed into the ground of the
auxiliary matrix belonging to it; also for the so-called
first-impression block.
It must be understood that colour printing can be done well only upon a
perfectly even and smooth surface, therefore it is wise with
first-impression blocks, as well as larger colour plates, to repeat the
impression, only slightly warm after having given a very hot impression
the first time.
Surface papers are an exception as they generally stand very little
heat.
It helps here either to let the newly made covers get half dry or,
better, to let them lie longer in a damp room.
When different colours are to be superimposed, the order in which they
are printed is a matter of some importance. As a rule, the so-called
warm tones (yellow, brown, red, or colours containing much of these) are
printed first; the cold tones (blue or others containing much blue)
being afterwards laid on. White is also classed as a cold tone, but for
technical reasons it must nearly always be printed first. If these rules
are observed, serious mistakes will seldom be made.
Moreover, proof impressions of the different colours must be taken upon
white cardboard, which should be marked for reference, in the same way
noting the proportion of the colours used in mixed colours. If the
outline block is to be printed in colour, it comes last; gold stamping
being done first.
The process of printing in bronze is similar to colour printing, as the
bronze is dusted over a preliminary impression in colour (gold upon red
or yellow ochre, aluminium upon white, coloured bronze upon a suitable
similar colour). Bronze is not printed upon colour, because the bronze
sticks too easily to such surfaces in places where it is not wanted; it
is then much better to use gold-leaf.
Should it be necessary on the score of economy to make a double working
in bronze, the cover must be previously washed with glair.
Leaf metals, pure or alloyed, are printed upon colours after they have
been slightly dusted with gilding powder, and with moderate heat. The
colours, however, must previously be allowed to dry thoroughly. Larger
surfaces are wholly prepared with glair to prevent the gold from
adhering where not required.
Most of the colours must cover well where it is not intended that they
should have a translucent effect. A good covering is not secured by
laying the colour on thickly but by properly mixing the colours, and
often also by giving a second coat after the first surface has dried.
Above all, one must avoid too thick and greasy colours. Black must
always be printed with a strong good covering colour, as must also the
outline block.
For colour printing, the press must be of the same temperature as the
room. In winter it is slightly warmed an hour before use, and when
necessary this must be repeated later.
There are quite a number of little dodges not easily communicated but
which are quickly picked up in practice.
Fig. 67--Stuck-on gauges.
Simple work is not adjusted by pins, but is pushed up to three guides;
moreover, the gauge of the press is not generally used, but three little
pieces of board are firmly glued to the table instead. The illustration
(Fig. 67) will clearly show the arrangement. At the letters A the pieces
of board are glued, to which the cover to be blocked is pushed up.
To prevent these gauges from being pushed off, or to facilitate refixing
in the event of their becoming loose, the gauge generally supplied with
the press is brought close up behind them.