New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1895-12-02
SCIENCE AND MECHANICS.
CARBON PAPER" IN PHOTOGRAPHY
From The Weekly Tribune.


bits Of engineering work. and the interior OF ',,
of a shop as we'll copies OF drawings ana W.
nents are continually being obtained by th'7 P :,
ess for business correspondence because 'he' 49,
s,orv so much more effectively than even '"e
most carefully chosen language Of cours' t,
one who learns to a camera for purely -.
purposes Is Liable to employ II occasoh'"'
Measure also obtaining souvenirs OF pleasure 'p'
reminders Of pleasant places and good ''''9' -
he gets in the way of looking for the p'o'u,
and artistic as well for subjects % ~
business interest But these other possioIe OR, ~.
tons OF his knowledge and skill only aHo'u -,
reason for acquiring them. In fact. person n'.u
to know how to take photograph ho"''"''
most as much as he does how TO write ~
After one has properly exposed plate ana hAS
given II the necessary chemical treatment ." '"'
developing" and fixing baths, he makes "r-
Der Of prints therefrom on prepared paper ~
merly most photographs were printed OH p"p
rendered sensitive 10 the action Of light WIN hlia
OF silver. Such pictures. like the pretty Wv
prints" often made by amateurs ION iei'
state paper. dre liable TO fade for hi'i'
industrial reasons however absolute permahehce
of the imag. is often desirable. To secure thls VIZ
tue and other qualities several new pap
have como into extensive during the last IL"
years. One which is attracting good deal VI "
tentlon lust now among ANA tours IL called "carooh
paper" and acquaintance with It's quaH'es anu
the method OF using II is worth culuVatins'
article consists OF rathe~ heavy paper coa'eu
with soluble gelatine with which certain DARK
pigment Chiefly carbon has been mixed one "a"
buy paper that will yield dead-black. oro~hish-
black greenish-back hues. For some suojeo',
the amateur will prefer one color TO another' anu
Will perhaps keep three shades III s'oeA'
When bought. the paper is not sensitive. IL eau
be exposed carelessly TO the HIGHT. therefore ana
will keep in good condition for years Inc pho.os
rapher prepares a solution OF absUs one ounce o. VI
chromate OF potash in thirty ounces OF wac
Into this bath. after a dip into cool. cIean "A'e,
10 render the paper limp the latter Is Immersed
for from one 10 four minutes In order TO sehs1t@e
H. The paper Is then laid nat. TO dry; and Wheh
It has parted with most o. the moisture X rhus'
be removed TO a dark place. With proper care j
can be kept from deterioratins about ten Gays OF
two weeks after being rendered sensitive
When a picture IL TO be made. piece OF 'H'@
paper Is placed under the negative IN iesu'''
printing frame and exposed 20 the light yer!
little experience tells the operator how long 10 ha'
before removing It He cannot judge py ihsPeC'0''
az ne can with silver or ferro-prussla'e PaPe''
however. Carbon paper like bromide paper o. al
ordinary ulate undergoes visible change "hen
exposed to light. In general way 1t may DC sa'a
however that in strong daylight the PRINT -
made almost three times as quickly as II "ouiu
be on silver paper. and In a subdued hgh' cuii
ousIv enough more than three times as quickly
Arothsr strange fact to be noted in this connection
% ha r. instead or pelng HnisHeu uP
the print be left in drawer or box ior several
aavs in total darkness the chemical action begun
during exposure continues little further In o'her
words the impression Is intensined II, thereto.e
such delay is anticipated. the printing shou'c 10
underlined a little ,u,
Tho rea son for the steps taken 10 render visible
m "devalon'' a picture obtained in this manner VIII
he be,,.r understood # the action or light upon
blchromatized film be borne In mind This erect >
70 render insolube gelatne that was before soluble
When therefore. the light penetrates ireey ''ousA
the TRANSPARENT places in the negative. II imprsohs
forever the pigment IN the material that hoids H.
pu. uher. the opaque parts OF the negative protect
IN. film the gelatine remains soluble and Will there
fore with proper treatment yieid up us eye anu
become coloriess. An exceedingly thin stratum oi
the film over It's whole upper surface Is however
GLAZED In the manner described; hence the washing
ont must be done from behind. And in order 10 get
AZ ts back the film needs to be remounted. race
downward, and the orgina! paper backing must DC
soaked off. From sheet OF what Is caiieu "a'i'
fer paper Is cut piece or the rishI sI" ms
when wetted becomes sticky on one SURFACE Inc
rhon print also IL dipped In cool water. TO render
:, linn and Is then applied to the transfer paper
,s back being gently pressed with an instrument
known as 'squeegee," 10 remove superHuouS
moisture and render the contact periect' Inc '"0
sheets are next placed under pressure Tor ten MIN
,,,es to promote their union. Finally, when 'hey
have been placed in warm water the Original sup
,orr gradually deiaches itself. The transfer paper
now, has a coating uniformly black but by ruDoihs
II gently the operator washes out the Tree caipo"
land some OF the gelatine with III. ana the pctuc Is
TINS fully revealed When no more aye can De
coaxed out of the film. the print is dried IKE any
other photograph: and that is the end OF H. Inc
Itch, has done the fixing: and the tone. which
,s given 10 SILVER print by means OF the gold
solution is impaired 10 the carbon paper by the
manufacturer in advance
One regulates the strength OF his image under
foIln uiDQ
nrir, from a thin weak negative he should use
naner senstized with a rather weak BATH This
tends to sharpen the contrasts between hghts ana
shaJovs II there are too great contrasts IN inc
negative and parts OF It are very dense then the
naner should be prepared with strong bath In
order 10 soften the general effect The rapldity OF
the action OF the light printing Cor. in other words.
tho constituencies Of the film depends somewhat
upon the quickness with which the paper Is dried
after immersion in the b-chromae solution After
a little one should get good manual ana STUDY
the fine points OF this part OF the process. Expe-
rence and brains. however Will quickly sho" no"
70 proceed in order 10 get the best results.
1t should be noted that by transferring the seia-
tine tissue has reversed his picture from right
TO left With SOM views this makes no diherehce.
But where 1t Is desirable 10 obtain true likeness
one resorts 20 what is called the double transfer
In the first stage the film Is affixed (face downward
10 a plate OF specially prepared glass wnich serves
Il merely TEN )orary support whle the Tree
carbon is being washed out. and when the latter
process is completed the transfer paper Is wetted
and stuck on to the gelatine The film Is next sep
arated from the glass and exposes TO the gaze
what was originally ts upper surface. Inc hgh
lights" or transparent parts OF the picture may
not be quite white the uncovered edges or the
transfer paper. but Will be su1icienty cear 10 SUIT
most tastes.
The slight bother incident 10 transferring the tbs
sue is, in the minds OF many photographers more
than offset by the cheapness Of carbon paper, the
great durability OF the pictures thus obtained the
abolition OF the developing. liking or tonins proc
esses and the possibility Of preserving certain deli
cate effects tas. for instance, light clouds In land
scape) which are apt lost in silver prints. 1t
certainly practicable TO get some exquisite pict-
urcs In this way. DR.. n. VI. Lewis. president or
the Brooklyn Academy OF Photography remarked
"A few days ago that about ~ per cent OF the prints
displayed al the exhibitions Of that wideawake and
progressive organization were made carbon paper.
and he thought that the new Idea was growing in
favor with amateurs.
NEWLY DISCOVERED VARIABLE STARS.