The Pacific commercial advertiser. [volume] (Honolulu, Hawaiian Islands) 1885-1921, 1892-05-24

With the increasing use Of half tone
work and the numerous processes for
book illustration that have been devel-
oped or adapted during the past ten or
fifteen years. there has steadily grown
tendency On the part Of publishers, proc
ess man, and in some instances among
critics, 70 apply entirely inappropriate
names TO the reproductions that are mis-
leading IL the extreme and cannot but
do an injury % the better classes Of work
by giving their names to processes much
their interiors in quality.
Let US first consider the ordinary hall
tone photoengraving Of which 50 much
has lately been seen IN the way OF illus
trations for the higher class periodicals
and works Of al art and technical nature.
We shall find that these prints all render
the half tone Of the original; or, TO be
less technical, show the various degrees
Of light and shade in masses Of color,
differing in degree, but in fiat tints, pro-
duced by breaking the original subject.
may have been either a wash drawing
painting in color, portrait from life or
view from nature, into and immense
number Of dots, obtained by photograph
ing through the fine meshes Of a ruled
glass In a manner not necessary Of de-
scription here.
The resulting picture Is transferred to
the metal that Is TO serve as the finished
plate; the chemical action is proceeded
with and the half tone plate that results
shows the picture in relief and the en-
tire surface Of the plate mass Of fine
points or dots, separated by fine burrows
running in transverse directions, the
points in relief being the printing sur
faces. The plate being blocked on wood
or metal to render II Of the same height
ar type. it Is linked mp with roller in
the same manner that type is, and the
ink, adheriDg to the points, is impressed
into the paper that Is brought in contact
with them in the printing press.
THE HALF TONE ENGRAVING.
| 1t should here be noted that the points
| or dots making up the printing surface
| Of the plate, being al Of the same height,
| the amount Of ink deposited On the paper
/ is Of the same depth or thickness from
| each and every printing point, and it
light and shade making up the picture
/ are dependent on the number and size
/ of such dots within given radius; thus
/ heavy shadow in picture printed
/ from relief plate will he seen to be com
| posed of a large number Of these dots,
/ often so close together as to merge into
! one another, while the high lights are
| the result of preponderance of the
| clear transverse lines that serve TO sep
arate the dots more widely, only show
ing them sufficiently to give form and
color to their object.
The above are the principal points OF
identification Of a print made from q
half tone type plate in relief, and are
easily to be distinguished from pictures
| produced from intaglio plates. There Is
still another kind Of half tone relief
work, however, that is not SO easily dis
tinguished, and this is the photogelatine
or heliotype and kindred processes, which
in rendering the gradations of color dc
not cut them up into dots, but lay the
ink in smooth masses of different tone:
on the paper from a surface Of gelatine
! PRINTING FROM AN INTAGL1O PLATE.
The photogravure is printed from al
intaglio plate, and is not capable of be
ing used in type press under any con
| ditions 1T can only be successfully
printed by an expert, and where with {
relief plate the Office boy might "kicl
| off" say 900 day, or the steam cylin
der press 10000, the expert printer will
his intaglio plate would not produce
| H.
plate is filed while warmed with {
hard, stiff ink, which is pressed int
every depression, and after the higl
lights of the plate are carefully wiped
off, by hand, the plate is run through
the press, III connection with the paper
and the latter lifts from the sunken sur
face OF the plate all the ink it has pre-
viously received, holding it on the sur
face of the paper in masses of color tina
differ in depth and consequently in tone
according to the depth of intaglio in diff
ferent parts of the plate, the result o.
which is series Of graduations from
the pure high light Of the clear paper tx
the rich velvety black of solid body
of ink spread over the surface Of the
paper and not pressed into it.
The grain, too, of this plate, instead
Of being composed of noticeable eros;
hatchings Of lines and dots, is a scarcely
discernible tooth, that is obtained BY
peculiar chemical action ON the
metal plate before the picture to b.
etched Is transferred thereto. Carbon
tissue being the medium through which
the transfer is made and the finished
print very closely resembling in most O
its features that beautiful pigment, it i
wonder that the feeling of those in
terested in seeing justice done to all hal
not been more forcibly expressed on thi
subject before.
A name that would answer the pur
pose and still be meritorious, is the OLE
title photoglyph, as it applies to al
plates which give reproductions from re
lief surfaces, while photogravure il
properly used only in the opposite con
nection. Let all, thea, who know bet
ter, be honest enough to call things
what they are and thus do what they
can to avoid further complication of thu
already multitudinoUs collection of pro
cess names in existence both in thi!
country and abroad.-Anthony's Photo
graphic Bulletin.
The AntipodeS.
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