St. Tammany farmer. [volume] (Covington, La.) 1874-current, 1888-06-16


Vasious Reliable Methods ~ which fhsy
Nay He Resesrsd.
The family album upon the draw.
ing.poon table i a never failing sab
feet of interest to visitors. and among
individuals who lack original ideas
forms an agreeable subject Of conver-
sa.ion in place Of that Of the weather.
OF late years. however. there is Enoge
diffidence in placing it in prominent
positions for the ready examination OF
waiting frieals. the sasl-colorsd plot.
nres Of 'rhe hue of a November fogin
Cheapside. or bad piece Of ginger
bread spoiled in tho baking" being
at variance with average ideas OF
artistic elegance. A more serious as
pect of the case is gradual discolora-
ton or fading of the ikenesses OF
members of the family who bavo
passed away by death. raising tho
question in the minds of survivors
what is to be done to preserve those
lineaments, for inspection. ere it 10
too late.
When the white parts Of an ord ina
~ photograph begin to turn yellow.
that photograph is doomed unless im-
mediate Efforts be made 10 preserve it
and those efforts may not always bo
successful Treatment with . weak
solution of bi-chloride Of mercury.
under the hands of skIliful pho o.
graphic practitioner. is one Of tho
best methods of making the attempt.
This may arrest decay. but will not
restore the likeness to the condition OF
. lrs:.rate photograph Bi-chloride
Of mercury or corrosive sublimate Il
highly poisonous and is best left alono
by the nniniuated.
4 better way Of preserving tie
msmento is to send the photograph
to . platinum printing or carbon
printing firm Of photographers in
sufficiently largo way Of business to
keep upon their. premises artists
skilled in tho use Of the brush AID
pencil Their usual plan then is to
obtain upon glass or paper an en-
lsrged positive copy Of the fading
eAotOgraph- This copy is IRE
:ouched." !" that is to say. worked upon
by hand so as TO remove obvious de-
fects due to decay or to original bad
work; a negative is taken from tho
perfected positive anil from this
negative any number OF copies may
be printed by Photographic means in
permanent carbon pigments or in
| platinum black. To obtain tho
positive already mentioned pri-
mary negative has to be taken. 50 that
two negatives are neeessitated BY tho
process, both Of which. ~ we'll rs tho
positive. are usually worked upon
somewhat by the hand Of the artist;
the method Of getting good perma-
nent photograph from a bad. fading
one is. therefore. complicated and re-
quires skill a. -sf,s II aU
In tho carbon process. carbon or
other suitable permanent pigment Is
spread upon paper or glass along with
solution Of gclatine and Of bicrOmato
Of potash or ammonia Where tho
light acts upon the surface through
the negative. the decomposition Of tho
salt renders the gelatinc insoluable;
consequently. when the paper is after
wards placed in warm water. the gel
atine unacted upon BY light dissolves
of in company with its pigment. thus
leaving the white paper exposed; but
where the hight has acted. the gsla.
tine and pigment remain to form the
shadows Of tho picture. These are tho
broad principles Of the process. omit
ting various practical details which il
would exceed present limits to Partic-
ularize.
The other permanent process. in
which the dark parts Of the picture
are formed Of platinum black. gives
tho most durable pictures known.
platinum being metal which has
moro power than gold of resisting
change under atmospheric and other
influences, indeed. platinum black is
infinitely moro permanent than the
paper upon which it is printed. In
some cases, either from badly pre-
pared sensitized paper or from faults
in the Photographic manipulatiens.
platinum prints have been known to
turn yellow in tho whites under tho
influence Of sulphurettcd hydrogen;
such disco loration has sometimes been
subsequently removed by the applica-
tion OF chemical reagents. without the
dark parts Of the paper having been
affected all through the operation
There are methods Of taking photo
graphs in silver which have exactly
the appearance Of platinotyPes. 50
that an expert can not always test the
difference without tho application OF
chemical tests; these black and en-
graving-liks silver prints are in all
probability much more permanent
than the ordinary photographs nsetl
for tho stocking Of albums -C"an'-
beSs' Jowrnat. sf
Ozone 40 q Cermicide.