New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1877-11-01
ALL ABOUT HELIOTYPES.
CHEAPENING ART WITHOUT DEGRADING 1T.
WHAT ARE HELoTYPTs f-How ARE THEY MApE'
-MrIAr Is TILE HEIIOTYPE PROCEssf


WHAT ARE HELoTyPEs i-How ARE THEY MApE'
WHAT is THE HEIIoTYPE PRoCEssf
These questions are so common that we pro-
pose to answer them fully and clearly as We can IN
uewspaper column, Messrs. James II. Osgood u CO..
who own the Heotype Process. have already iamu'I-
lied the public with the Words and have conveyed 10 All
minds their general import namely, that the tehope
in its broad mode Of reproduction when erNeS
10 popularze tho works Of art by means OF copies
that represent the originals with feultess precision
Bnt how Il IL donei What the process We viii en-
deavor TO explain as clearly possible the principle ana
the successive steps.
Tho elioype Process was invented in London in 1870
by Ernest Edwards who considered the word " Hello
tyne TO express the results OF his invention II IS de-
rived from two Greek words HeOs the and Tupos
type. and thus signifies literally " SunlType." But
broadly much more than that, rs we shah soon
see The process introduced into the United states
IN 1872 by Osgood Co.. and Mr. Edwards, the inventor
of has from that date its superintendent under
their auspices
The Hclctype Process is the application Of the we'll
known principles Of photography the Of printing,
and the practice Of the prntinspress. Photography is
purely chemical tor actnic) process, as IFS name
writing bv light y implies Printing. on the other hand
is purely mechanical. The Hclioype Process is both
chemical and mechanical. combining the chemical prin
cipes Of photography with the mechanical methods of
printing In short. the Heiotype Process may be com
prehensively described photography in the printing
press.
WHAT Is 4 HEIOTYPEf
The product OF the Hei0ype Process is called HeO-
type is both photograph aud print; it is photo
graph mechanically produced, and it is at the same
time print having a chemical origin. The ordinary
Photograph produced in evanesccnt materials, and
will flde the Hcotype printed with permanent ink.
and can fade The Hciotype, therefore. may be
defined photouechanical PRINT possessing the exact
Of photograph together with the permanent
qualities OF ordinary printing.
appreciate the fun bearing Of the Helotypc Process
IN working ont its results ii is necessary 10 understand
little OF photography, and how the ordinary Photograph
is made Almost everybody has sat for photograph.
and knows that there steps the process First
obtaining the IMAGE on glass plate, by means
OF camera, placed in front OF the subject
and second. producing its counterpart on
sheet Of paper The glass plate is called meg
alive ;" it's counterpart paper technically termed
positive and is what in ordinary phase we call a
photograph both these steps the Photographic ope
raOr dependent lGhibOih Of the results chem
ica The negative" is produced by light acting upon
the material with which the glass plate In the
camera is coated; as soon as chemistry firmly fixed
the chproducd image the glass plate, the plate is
placed in contact with sheet OF sensitive and the
action light again invoked impress the image
upon the paper and produce the positive" or,
say, "the Photograph" Now let us bear in mind inn
pOrtant fact, namely that each and every one
Of these "positiyes." or photographs" requires
10 light produce IT, thus making the method Of pro-
ductOn slow cumbrous and uncertain 1t is this point
that the Helotype Process beg think of separating
itself from chemical uncertainties and Of bealng itself
10 the surer ground Of mechanical methods How il
10 proceed then! 1t already has its negative" winch
is taken precisely have described the Photographic
negative TO be taken what It now needs Is to pro
duce its "pOstives" by rapid and means
To do this it must first procure "posi
tive" plate matriX, capable of mechanically
producing other "pOstyes," ard thus dispensing with
the continued Use Of the negatiyc" and the continued
use OF light in every impression How this positive"
plate is obtained Of what it is constituted and how II is
used. shall shortly explain. To up difference
then. between the Heloype Process and ordinary pho
Biography, may that while both start with the
prnciPethe Photographic negative being in each the
key TO the sitUau0nthe Photographic process employs
the negative and the agency OF light for every posi-
tive" It makes. while the HelotyIc Process the
negative as a of procuring positive and
this positive is capable OF producing infinite
Der OF others by the ordinary Of printing with
printers ink pIn'iugpress.
HOW TIRE HEHOTYPE PRlNTiNG-PLATE Is MADE.
We have already that the negative" is made in
the ordinary manner. Now come 10 the preparation
of the positive" plate. Ordinary cooking gclatine
the basis Of this Uatc the other ingredients being
bichromate Of potash and chrome alum. II is a pccu
arity OF gelat.ne IN its normal condition that il VIII
absorb cold water, and swell expand under nfiu
cnce. but that will dissolve in hot In pre-
paration the plate therefore. the three ingredients
Just named being combined in suitable proportions
dissolved in hot and the solution poured upon
level plate Of glass or metal, and left there
to dry When dry it is about thick as an
ordinary sheet Of parchment, and is stripped from the
drying plate and placed in with the previously
prepared negative" and the two together exposed
10 light The presence of the bichromae of potash
renders the gatne plate sensitive 10 the action Of light
and wherever Heht reaches it, the plate, which
first geianous or absorbent OF water become eahery
and waterproof In other words whenever light reaches
the plate. it produces in IL change similar to that
which tanning produces upon hides in converting them
into leather. Now II must be understood that the
operative is made up Of transparent parts and Opaque
parts the transparent parts admitting the passage Ofght
through them aud the Opaque parts excluding IT, When
the geatne plate and the negative are placed in
tac,. they exposed to light with the negative up
permos that the.ght acts through the translucent
portions ana waterproof the gelatne underneath Them
while the opaque portions II The negative" shield the
gelatnc underneath from the light, and consequently
those parts Of the plate remain unaered in character
The result is a thin flexible sheet Of Geatine, of which
portion is waterprooed, and the other portion
is absorbent OF water, the waterprOoed portion
being the image which we wish to reproduce. Now we
all know the rcpulson which exists between and
any form Of grease Printers ink merely grease united
with "a coloring matter. II follows that gelane
sheet having water applied 10 it Will absorb the in
its unchanged parts. and If INK is then rolled over H. the
ink will adhere only the waerprOOied Oh altered parts
This flexible sheet Of geatinc then, prepared rs W. nave
SEEM and having had the image impressed upon II
becomes the positive" plate from which we may null
tPy impressions to an indefinite extent ny uechahlca
In other words. " j. the HcOjype plate capable
Of being attached 90 the bed Of an ordinary printing
press ana printed in the ordinary manner II would
hardly b. supposed that this apparently ira
spongy. could withstand the rough usage that
necessarily attends printing form But he iact is tat