Thomas George Hill.

The essentials of illustration, a practical guide to the reproduction of drawings & photographs for the use of scientists & others online

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Reader in Vegetable Physiology in the University
of London, University College

28 Essex Street, Strand





Intaglio plates 2

Line engraving 2

Etching 5

Soft-ground etching 6

Mezzotint 7

Photogravure 8


Lithography 15

Chromolithography 20

Photolithographic processes 23

Collotype 23

The preparation of illustrated pages 26


Woodcuts and engravings 33

The Half-tone process 37

The Half-tone three-colour process 46

Photomechanical line blocks 49

The drawing of microscopic details 67

The drawing of diagrams and apparatus 72

The drawing of maps 76

The drawing of graphs or curves 79

The swelled gelatine process 84

The Relative Cost of blocks and plates by
various processes 89





1 An original lithograph by Mr. Harry Becker.

2 Chromolithograph. Messrs. Gerrards, Ltd.

3-5 Collotype. Messrs. André, Sleigh & Anglo, Ltd.

6 Half tone. Swan Electric Engraving Co., Ltd.

7 Half tone. \
8 Photogravure. |
9 Collotype. | Messrs. André, Sleigh &
> Anglo, Ltd.
10 Half tone. |
11 Half tone. |
12 Half tone three colour. /


Tailpiece, p. 11. Electrotype from the original wood
engraving by Bewick.

Tailpiece, p. 30. Line block. Messrs. Bourne & Co.

Fig. 1. Wood engraving.
Messrs. Edmund Evans, Ltd.

Fig. 2. Wood cut. Mr. G. N. Oliver.

Figs. 3-6. Line blocks.
Messrs. André, Sleigh & Anglo, Ltd.

Figs. 7 and 8. Line blocks, reproductions of a wood
engraving. Mr. C. Butterworth.

Fig. 9. Line block.

Figs. 10-13. Line blocks, reproductions of wood

Fig. 14. Line block.

Fig. 15. Line block.
Messrs. André, Sleigh & Anglo, Ltd.

Fig. 16. Line block.
Swan Electric Engraving Co., Ltd.

Fig. 17. Line block.
Messrs. André, Sleigh & Anglo, Ltd.

Figs. 18-20. Line blocks.

Figs. 21-23. Line blocks. Messrs. Bourne & Co.

Figs. 24 and 25. Line blocks.

Fig. 26. Line block. Messrs. Bourne & Co.

Fig. 27. Line block.

Figs. 28 and 29. Line blocks.
Messrs. André, Sleigh & Anglo, Ltd.

Fig. 30. Line block. Mr. C. Butterworth.

Fig. 31. Line block.
Messrs. André, Sleigh & Anglo, Ltd.

Fig. 32. Line block. Mr. C. Butterworth.

Figs. 33 and 34. Line blocks.

Figs. 35 and 36. Line blocks.
Messrs. André, Sleigh & Anglo, Ltd.

Fig. 37. Line block. Messrs. Bourne & Co.

Fig. 38. Lithograph reproduced by the Swelled
Gelatine Process.
Artists Illustrators, Ltd.

Tailpiece, p. 86. Line block.
Messrs. André, Sleigh & Anglo, Ltd.


Modern scientific publications, although they may in some or even
many cases equal in their scientific quality the memoirs of earlier
workers, do not, on the average, reach a high standard as regards
illustration. For instance, in Great Britain botany is pre-eminent
in its morphological aspects; it should therefore follow that the
illustrations, which form so important a part of such papers, should
be beyond reproach. This is not always so, a fact which must be patent
to anyone with the slightest critical knowledge who looks through a
typical journal. This is a fact much to be regretted, since many of
the earlier scientists were accomplished draughtsmen and, indeed,
often artists; in this connection the Hookers and Professor Daniel
Oliver may be mentioned. The implication is not intended that there
are no good amateur draughtsmen nowadays; there are, and in some cases
possessed of great ability. The beautiful work of Church in his Floral
Mechanisms may be cited as an example.

It may, of course, be argued that any picture which serves to
illustrate the particular feature is good enough; this is the
contention of one who takes an insufficient pride in his work. A
feature worthy of an illustration deserves the best the author can
produce, more especially as a literary form is still, fortunately,
preserved or, at any rate, aimed at.

The reason for indifferent illustrations is primarily due to bad
or mediocre drawings, or to their unsuitability for the kind of
reproduction in view.

With regard to the first point: this lack of draughtsmanship often
obtains; when education entirely replaces mere instruction, it is to
be hoped that all students of science will be trained in the rudiments
of drawing. Meanwhile the difficulty can be partly overcome, as will
be seen later on, by the simple means of drawing on an enlarged scale,
in order that in reproduction reduction can be made.

The second reason, the onus of which also falls on the authors, is
a lack of knowledge regarding the kind of drawing suitable for the
different modes of reproduction; this is a very important point, for
"technical conditions govern even genius itself."

Authors, however, are not always to blame; it would appear that even
editors sometimes are wanting in the requisite knowledge, for we have
known straightforward line drawings reproduced by half-tone; in other
cases the paper used is unsuitable for the reproduction and, at other
times, the printers are at fault.

With a view to remedying, at any rate in part, these deficiencies, a
course of lectures, arranged by the Board of Studies in Botany of the
University of London, was delivered in the Lent term of 1913 in the
Department of Botany of University College, London.

In gratifying the wish expressed by some that these lectures should
be given a more permanent dress, the author feels that some apology is
necessary, for he can lay no claim to authoritative knowledge of much
of the subject-matter; questions relating to the graphic arts and to
illustrations, however, have always been of interest to him, so that
he has tried various experiments, often with disastrous results, and
thus has gained some experience.

In these matters the author has benefited much through his association
with Professor F. W. Oliver, who, characteristically, has been ever
ready to discuss these problems with, and to place his knowledge and
experience at the disposal of the author.

The outline of the ways and means of illustration contained in the
following pages is primarily intended for ordinary working scientists,
not for artists, professional draughtsmen or skilled amateurs.

The point of view is mainly botanical, primarily because the present
writer is a botanist and also because the requirements of modern
botany in the way of illustrations are more extensive than those of
any other science; the requirements of other sciences, however, have
not been overlooked. With regard to other branches of knowledge, the
principles considered will, it is hoped, prove of some value to the
workers therein.

The details of technique have been kept as brief as possible; in
fact, sufficient only has been said to indicate the main principles
involved. In the literature cited, to which the author is indebted
particularly for matters relating to technique, will be found full,
and sometimes exhaustive, accounts.

With regard to the illustrations, these have been selected to
illustrate the various methods of reproduction described or to
demonstrate the points raised. In those instances where the source has
not been acknowledged or the draughtsman or photographer mentioned
by name, the figure is by the author: and since the actual making
of plates and blocks is of considerable importance, the firms, when
known, responsible for their making are mentioned in the Table of
Illustrations. In this connexion the author desires to express his
appreciation of the skill shewn and care taken by Messrs. André,
Sleigh and Anglo, Limited, who prepared the majority of the new
illustrations which appear in the following pages.

The author is indebted to many who have helped in various ways in the
production of his work; particularly is he desirous of expressing
his warmest thanks to Miss O. Johnston for the charming drawing
of _Geranium columbinum_ (Plate 2) and to Mr. Harry Becker for
his beautiful lithograph (Plate 1). To Miss S. M. Baker, Dr. W. G.
Ridewood, and Miss Winifred Smith thanks are due for the loan of
original drawings; also to Mr. Edward Hunter and Mr. Hugh Hunter for
information regarding matters of technique and cost.

The number of illustrations would have been less but for the
generosity of Messrs. Chapman and Hall, the Editors of the "Annals
of Botany," "The Imprint," and the "New Phytologist," Professor F. W.
Oliver and Mr. G. N. Oliver in lending blocks. Recognition also must
be made of the kindness of Mr. Richard G. Hatton in consenting to the
use of certain blocks from his admirable "Craftsman's Handbook,"
of the Delegates of the Clarendon Press for permission to reproduce
figure 14, and of Messrs. Frederick Warne and Co. for permission to
make use of the wood engraving by Messrs. Edmund Evans, Ltd., of Kate
Greenaway's charming Milkmaid. Finally, the author desires to express
his sincerest thanks to Mr. Gerard T. Meynell, of The Westminster
Press, for the keen interest he has taken in the work, for his help
with the illustrations, and for the great care he has taken in the
production of the book.

University College, London
_January, 1915._


In the biological sciences the massing of illustrations into plates is
still the favourite method of illustration, although text-figures have
recently become more numerous.

This is partly due to innate conservatism, for most of the earlier
memoirs were so illustrated, doubtless because it saved time, since if
wood engravings were used with a view to text-figures, the compositor
had to wait for the blocks, whereas in the case of plates the
compositor and the engraver worked independently. Also the
possibilities of plates are enormous; they may be very beautiful
indeed besides being biologically satisfactory, for much finer results
can be obtained by engraving metal than by engraving wood. Then again
there are many different processes available for the making of
plates, so that if one proves unsuitable for a subject an excellent
reproduction may be obtained by another.

Before passing on it is desirable to point out the essential
differences in the three ways of printing.

_Intaglio printing._ If the finger-tips be examined, many ridges and
furrows will be seen on their under surfaces; if now a thick ink
be well rubbed into these so as to fill well the furrows, and the
superfluous ink be wiped off from the general surface, an impression
will be obtained of the furrows on pressing the fingers on to a piece
of smooth white paper. Better still, if the copper plate of a visiting
card be examined, the name will be found cut into the surface. If an
intimate mixture of tallow and lamp-black be well rubbed into these
depressions and the excess of ink wiped off the surface of the plate,
an impression can be obtained by placing a piece of damp paper on
the plate and passing both through the domestic mangle - the kind with
rubber-covered rollers. In each case the principle is the same, the
pressure forces the paper into the depressions of the plate so that it
takes up the ink.

_Plane surface printing._ This is characteristic of lithography and
allied processes. Writing or a design well chalked on a blackboard
can be transferred on to a smooth piece of paper merely by a little
vigorous rubbing on the back of the paper placed in position over
the drawing. The transfers of childhood provide a further simple
illustration, so also does the hectograph (jellygraph).

_Relief printing._ In this case, the design is raised above the
general surface of the substance. A rubber stamp is an obvious

It will be noticed that intaglio and relief are the reverse one of
the other, whilst plane-surface printing is intermediate between these
extremes. In intaglio, the ink is taken from a depression; in relief
from an elevation; and in flat printing from a plane surface.

INTAGLIO PLATES. There are several methods of making intaglio plates,
but only a few are used in the illustration of scientific papers;
attention however may be drawn to the others, not only for their
own sake, but also on account of their influence on some modern
photo-mechanical processes.

LINE-ENGRAVING. Line engraving, by which is meant cutting lines into
copper, steel, or other suitable material with a burin or graver, is
a very ancient art. Its employment for illustrative purposes is an
outcome of the art of the metal workers - particularly the Florentine
goldsmiths of the fifteenth century - who filled up the lines cut in
the metal with a black enamel of silver and lead sulphides (niello)
which was made by heating together a mixture of these metals with
sulphur. This enamel when once in was very hard to remove, so that in
order to see how their lines were progressing, the artists rubbed
well into the metal, in order to fill up the lines, a sticky ink. The
superfluous ink was then wiped off the general surface of the metal
and a piece of paper was placed in position and pressed sufficiently
hard to make it enter the depressions, which alone contained the
pigment, and take up the ink. A print was thus obtained of the work
and so its state was ascertained.

Metal engraving is carried out in the same fashion at the present
time. A flat plate of copper or steel is well polished and is worked
upon with a graver or burin, so that the picture is represented
by lines cut into the metal. Any line, however fine, will give an
impression on printing, hence it is hardly surprising that engraving
has long been a popular means of expression by artists, since force,
depth and delicacy are possible of attainment.

The printing is carried out in exactly the same way as by the early
metal workers: the plate is covered with a thick ink which is forced
well into the lines and then the superfluous ink is removed. The plate
is now ready for printing; to do this, the plate is placed in the bed
of a copper-plate press and over it is laid a sheet of damped paper
which is covered with two or three layers of blanket. The whole is
then passed under the roller which forces the paper into the incised
lines, so that not only is the ink picked out, but a mould of them
is taken on the paper, hence the very finest lines will give an
impression. Having passed through the press the paper is carefully
peeled off, and thus the print is obtained.

With regard to the metal employed, copper is commonly used, since
it is soft and easy to work; its softness however is, in a sense, a
disadvantage, since the plate will soon wear, the finest lines being
the first to go, so that a limited edition of good impressions only
is possible. To overcome this difficulty, the plate may be faced with
steel, by which means it is rendered very durable.

Steel, although once popular, is not much used nowadays owing to its
hardness and the rapidity with which it rusts. As compared with copper
engravings, steel gives a somewhat harder line, whilst copper gives
a soft line, but this, of course, does not mean that steel engravings
are harsh; the finest work can be done on steel and of remarkable

At the present day line engraving is seldom or never used as a means
of illustrating scientific work. It is obvious that the average
scientist has not the time and he certainly does not possess the skill
to make his own plates; the engraver must translate the originals into
lines, so that much consultation would be necessary. Further, a
line engraving takes a long time to make, and most publishers would
certainly look at the expense.

In the past, however, the line engraving was much used, and very
beautiful work was often accomplished. The following works contain
outstanding examples.

Bojanus: _Anatome Testudinis Europaeæ_, Vilnae, 1819-1821. The
plates are beautiful engravings by Lehmann after the drawings
by the author.

Chatin: _Anatomie Comparée des Végétaux_. Good steel
engravings illustrating the structure of various plants.

Curtis: _Flora Londinensis_, London, 1777. The illustrations
are hand-coloured copper engravings by Sowerby and others,
many of which, particularly the earlier ones, are of
outstanding excellence. The engraving is often nothing more
than the mere outline of the plant, whilst in cases where the
structures are more massive, a certain amount of shading is
used. The colouring is very good indeed, and it is obvious
that much care was taken not only in the actual painting but
also in the choice of pigments which, as far as can be judged,
are as fresh now as when first used.

_Curtis's Botanical Magazine_ and _Edwards's Botanical
Register_ contain some excellent examples of hand-coloured
copper engravings.

Levaillant: _Histoire Naturelle des Oiseaux d'Afrique_. Paris,
1805-8. This work contains beautifully coloured engravings by
Feesard. The original drawings were by Reinold.

Lyonet: _Traite Anatomique de la Chenille_. La Haye, 1762.
The plates are amongst the best illustrative of zoological

Martius: _Flora Brasiliensis_. The earlier volumes, _e.g._,
Vol. 13, Part I, contain excellent engravings.

Passæus: _Hortus Floridus_. Arnheim, 1614-17.

Sowerby and Smith: _English Botany_. London, 1790-1866. The
illustrations are hand-coloured copper engravings.

Thuret et Bornet: _Etudes Phycologiques_. Paris, 1878. This
work contains the finest plates ever published in a botanical
work. Riocreux drew from the preparations, and his drawings
were engraved on steel by Picart, Thomas and others.

ETCHING. Etching is a term very loosely used; strictly speaking it
consists in corroding a metal plate or a flat stone with acid, or
other substance possessed of a kindred action, so that depressions are
formed. A pen and ink drawing, although usually so termed, is not an
etching. Briefly the method is this: a well polished copper, steel or
zinc plate is covered with a substance, known as the etching ground,
consisting commonly of a mixture of asphaltum, white wax and pitch,
which resists the action of the acid. The ground may be laid in more
than one way; the simplest, perhaps, is to dissolve the etching ground
in some solvent such as chloroform, which readily volatilises, and to
pour the solution on to the plate, which is tilted this way and that
until the liquid is evenly distributed; the excess is poured off and
what remains is allowed to dry, the plate being kept level during the

The plate is then warmed until the ground is softened, when it is held
over a smoking candle and is rapidly moved here and there so that if
properly done the fine soot is evenly incorporated in the ground.
When the plate is cold, the drawing may be made by cutting through the
etching ground, so as to expose the underlying copper, with needles of
various sizes. The work is then etched by means of dilute nitric acid.

When this is satisfactorily accomplished, the ground is cleaned off,
the plate well inked with copperplate ink, and the surface ink removed
by coarse muslin. The plate is then gone over with fine muslin, but
the ink must not be removed from the depressions; finally the damped
paper is placed in position and impressions obtained by the use of the
copper-plate press.

Etching, although suitable, especially when natural-printed,[A] for
the illustration of many scientific subjects, is but seldom employed
at the present time for this purpose; the preliminary announcement
of Warburg's _Die Pflanzenwelt_, however, states that some of the
illustrations are etchings.

[Footnote A: A plate is said to be natural-printed when all
the ink is removed except from the depressions; in artificial
printing some ink is allowed to remain on the flat parts.
Artists frequently, after removing the superfluous ink,
lightly dab the plate in order to make the pigment spread
slightly beyond the actual limits of the depressions; this is
known as _retroussage_.]

SOFT-GROUND ETCHING. This is a somewhat rare method of reproduction
nowadays; it may, however, be described briefly, for it would appear
to be suitable for scientific purposes, since it should not prove a
matter of great difficulty for an author who is a sufficiently skilled
draughtsman to make his own plates. The polished copper plate is laid
with ordinary ground to which is added lard in a quantity according to
the warmth of the weather.

Over the plate is then placed a sheet, larger than the plate by an
inch or two, of damp, thin, grained paper, the edges of which are
folded over and pasted to the back of the plate. When the paper is dry
it will be well stretched and in close contact with the plate. With
the hand resting on a bridge, in order to avoid inadvertent touching
of the plate, the drawing is made on the paper with a pencil of a
hardness suited to the softness or otherwise of the etching ground.
When the drawing is finished the paper is carefully removed; wherever
the pencil has been used, the etching ground will adhere to the paper,
so that in such places the metal will be exposed. The plate is then
etched and printed as in the normal process.

No reproductions of drawings of scientific subjects apparently have
been reproduced by this method. Examples can conveniently be examined
in _The Seven Lamps of Architecture_ by Ruskin.

MEZZOTINT. The characteristic feature of mezzotint is that the
subject is translated into tones rather than lines as in the preceding
intaglio methods.

The surface of a smooth metal plate - usually copper - is raised into
innumerable and minute projections by going over it in all directions
with a curved steel tool, known as a rocker, the edge of which is
finely toothed. An impression taken of the plate in this condition
will give a deep rich tone. The high lights are obtained by scraping
and burnishing away the elevations so that there are no pits left
to hold the ink, and, similarly, intermediate tones are produced by
partly removing the pile so that the pits are made of varying degrees
of shallowness and consequently will print in tones according to their

Impressions are taken in the same way as in the case of etchings.

Mezzotint apparently has never been used for the reproduction of
scientific subjects. Indeed, in a sense, this process is much too
artistic for the purpose. At their best, illustrations reproduced
by this method have mystery and depth and give the imagination

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Online LibraryThomas George HillThe essentials of illustration, a practical guide to the reproduction of drawings & photographs for the use of scientists & others → online text (page 1 of 6)