New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1893-02-26

Is TO soak the plate In water few minutes and then
| transfer It TO a bath made OF
Dchro,nac potassium u dam
Let tho Plate stay In THIS ba:h until sufic'h'y re-
dnccd after which give Il a thorough Washing MIN,
notcs are found whlch require only slight local
reduction For this purpose use solution composed o'
Hvposulphitc Of soda % ssaims
Rcd pIu>siac ~ lotl o,nrrs
TN. plnc should be soaked I'm water until III" film
Is soncncl and the reducing solution applied with Il
soft brush to the spots requiring 1t, ana the Pi'''
thoroughly washed. or. after soaking IN" pa'e' Il
weak solution Of chloride Of lime may be- app'u anu
n the Intensity Of the plato Is noticed during develop
mcn the lime may be applied then, after hAlhg anu
washing.
There Is a great deal Of misunderstanding rs 10 'h'
relative pcrmancncc Of Intensified negatives aS com
parcd with those not treated anu also rs 10 '"'
real cau,c oi the deterioration when u occurs y
careful examination Of negatives which hay" gone
wrong after being doctorcd VIII show thai III most
cases # + not that the image has faded, but that the
clcor pOrions have become diScOlorcG ana hll"d up
and IT should be- remembered that II Is upon tho care
,I treatment Of negative previous to in"nSlhcn'ioh
that IFS pcrmancucy depends and the impor'anc" OF
4 perfect washing Of ia" plate Will b" explained
When mcrcuric chloride In solution IS applied TO
a gcatinc film the metallic silver forming III" mag
abstracts a portion ~ III" 'hlpHn' ''"" -"
chloride and IS converted chloride Of silver while
the mercuric salt IS reduced 10 the morcnron' state
with c,la,nc negative the same Wilderness cannot
hc obtained ID. with one of c0,fon result pc ''lbf
duc to the ccatIno Itself and partly. also. to The I'M
perfect removal 81 ,oull" matters from h' MN
slight trace Of developing stain" iuNiNbl" before
the application Of the iutcusner. becomes p"h"'N
apparcni when Tie ncgltly" has passed through ne
mercury bath. while tho product forming Tie maj
Image are % far as any treatment they may haN" 10
Undergo perfectly permanent. much doubt has been
cas-, upon the stability Of NEGATIVES intensified IN
this manner and many ama''u r' hav" con" =" lar
., utterly TO condemn mcrcurial treatment rs III"
trustworthy Condemnation. however. does not ey
plain the numc,l, instances 81 negatives WINCH '''
stood for year, after being treated with mercury.
Tile pou, +, really one 81 sufficient or insufficient
shin. before and after the ~" OF ia" blohlorld"
solutlou MANY an amateur will say "l AWAY, wa-h
ms negative, carefully" but while tho washing aud
care were there thoy were not combined The guam
iity ~ water wll, pa>"- over plat" ana the unle
taken In doing 1t ar FAR from being a m'ASur, 81
The result of placing an lmp"rf"ctly w1-h"d pIai'
in mo bicAloridc solution I. TIT, In" pore, 81 III,
Ain. II not fnli o. a. lc2st contain 1%nr Ey
H. reaction 81 hc-" substances Their" may h" i"rm'u
q, well as caomcl. Will" any NTo s'nih III a.. w.
gelatin" become, permanently hA"i lh'I" Nv ~
hardening action Of 3D." mercury i u aLN ""n n'
that such plate. oven II II J." not .poi'u VI o"'''
should later ,how sign, 81 deterioration
of dsvcorn.nf .hould be- .horouch lv washed. Ana
Ills washing ,hould Doc done whether N" plat" Is
IA be- d65Toref or not. for m cNc"'dingN ,mAl
amount Of hypo "i In ne pores oi The g"lanr h cn1
and temporary iutcusihcliion a handy mrthnn u 10
0ppy Win fAr finger indigo bin" mol'i"n"d Win gun
intensity enough 70 tighten deep ehadow- though IL"
struCtiNe Of detail.