, 1875-10-17


anything more than eyanescens shat
OWE, other processes must replsce 81
ver-printing. Inventors. therefore, have busie
themselves dey1sing ways OF printing photo
graphic negatives into some permanent material
aud the result has beeu great variety 0; pro
casses known aR photo -lithOeraphy, photo-zincoR
raphy, helIotypes. the graphic process, Swans
! Dllvet's, Wo1dburys processes, etc.,-most o
which are methods OF transferring the impressio,
! OF the negative to some substance such as stone
zinc, or electrotype plate, from which prints cal
| be made With printing inks al in ordinary en-
craving. L viii be seen that this method differ
| materially from ordinary photography, since i.
] the latter the action OF the sun does all tn,
f! Printing, while IN the former the agency OF tht
sun ceases-at the same point with that OF tht
] eng1avar-at tho production OF q single picture
| upon the Stone OF copper plate, which is multi
pied nv means similar to the ordinary processes
| Of printing.
In printing upon stone or zinc there is no re
| Lief in the plate but the printing is dependent
| upon The different chemical afinities Of the inI
| for different parts OF the stone or metal. II
copper aud eteet plates, On the contrary, the
printing is entirely dependent upon differences
in the relief, and the atm Of the inventors Is tc
make the Photographic negative impress IN i'm
age OF ltFolf in
PERMANENT RELKF UPON THE PLATE.
This is what is accomplished b. the process Of
Woodbury., Of London, which ls applied to the
0u3Atll IhkI6ly anu u1l0y Ot0eF WOfk9. II 1E
dependent upon tho quality OF geIatine (which
is substantially common glue somewhat finely
prepaIed) when com olned with bicEromate OF Co-
tassium, O substance we'll known to photograph
efs, Of becoming. On exposure to light. insoluble
in water. The parts unaffected BY light can ba
washed away and the insolub!e portions are left,
forming picture in relief. 4 plste Of soft
metal ia applied under powerful pressure to this
picture, and sunken impression Of it is OBJ
tanned which Is used in printing. In the re-
port OF the United States Commissioners to the
Paris Exposition of 1867, the Following descrip-
ton Of WoodbuEytypes is given:
The process Of Woodbury. Is carried On thus: 4
aheet Of geatine Is placed upon thin sheet Of mca
and soaked in bichFomate solution {glae, h1glass,
and potash IRE more familiar names1; It Is then p.ced
with the mica side to the negative and exposed to the
light after exposure the soluble portion OF the gea-
as dled II. md pctu1s as ptSF TSea is
reds placed upon clean pate OF lend other soft
meta hydraulic pressure is applied the gelat1no pic
for printing In the following manner few drops Of
warm geatine mingled with any desired pigment are
Piled with gnssplat other fat surface the super
niled With ho ink nd The 7srying thieknsss q tie
Many Of the specimens are remarkably beautiful and
they cannot ordinarily be distinguished b7 the casual
observer from the finest photographs. The process is
that great future IN this art is hero opening There
are many practical difficulties to overcome but the
process is IN all respects oue OF great promise.
Ordinary printers ink cannot be used in this
process, for this reason In ordinary steel and
copperplate engraving the picture is made by d
great plumber of sunAen lines aud dots scattered
over tho plate, which, when ink ia applied aud
the plate wiped OF, retain portion OF the ink
caught IN them and Impress their shape upon
the paper. 4 Woodbu1ytype plate, however.
has no such lines and dots, but broad. sunken
places where there are shadows, shalower de-
pressiops in the half shades. and the face Of the
plate in tue lights the depth OF the depression
beng precisely graduated to tue shadows. It is
wiped oil. the ink would be wiped noe only
OF Of the lights but from the broad
shadows also, ana the picture destroyed. 1t Is i
therefore, to use gelat;nous ink,
and to 40 the wiping BY pressing plate OF glass
upon the engraved plate
Hamerton's art Journal, the Portfolio makes
Use OF
A FRENCH PROCESS OF sPHoroanAvuRc,
or sphoso- engraving, for the reproduction Of
works Of art. which is spoken Of as "Goupil's
process" This is said to be substantially Wood
3urys process, somewhat modified OF improved
" N. Roussellon, foreman OF Goupil's A de-
'ct1Ftlon OF an improvement on Wcodburv'e first
process is given BY G.. ". Simpson in the phila- |
lelphia Photographer OF May 1870, which is
Identified by the editor Mr. Wilson. a. tho same {
la Goupll8 process It ia in the following
yords:
He tAir. Woodbury. was in the habit Of adding lit
le cooring matter to the Qelat:ne from wbIch his
eefs we're formed aa IN ald to examining their prog
ess "a dsseopmspt; IN thia occasion (abous twelve
a: oe1Gae % IanneaIan1s from some unexplained
stsn md " 9en u - "a IA. nt
eief surface resembling that Of yerv ns aSnsfn+e
late. When this effect first produced discuss-
with Mr. Woodbury. the chances Of utilizing It az IN
I'd to producing photographic engraved plate for
h p.a'G M psnhg Inc me 1aea tnus canyassed, Mr.
sne Fran M 0t e,,nn,stea OUT It, . INC present
! lead or tSpe-mc;sl t is obtainea dn''eho no
yd1auuc pressure; but, as such plate would be too
of for valuable service IN tho mode Of printing en-
loyed With coppe1Eates, It Is desirable to proceed
,s atts ns sol. meta pase .aess1ore placed in
m this ~ mold annthaF n,e;o II 1Ine. n;nt oo,anea
thu tntterv This 1axr - tha ~ @ 1t -