Evening star. [volume] (Washington, D.C.) 1854-1972, 1893-02-25

nrst make print ~ usual on silvered paper.
Then an experienced artist must draw on that
print In India ink such lines - will reproduce
the lkeness The next step is to apply solu-
ton Of bichloride Of mercury to the drawing to
bleach out all the Photograph between the
lines, leaving black lines q white ground
Then take another glass negative Of this black
line picture Of the exact size the engraving is to
be, and after drying it coat II with transparent
rubber cement. This joins with the collodion
and forms a tough film. which may be sepa-
rated from the glass by soaking in water
These delicate films which now show you are
samples after service The film il now TO be
floated upon water and then taken out the other
side up by placing q glass under 1t. aud yhen
the air bubbles are carefully brushed out and
the plate Is dried the film adheres 10 IL like
this one and il is ready for use. The film is
thus separated from the glass for the purpose
it was q negative and it would print
a positive, but we want our zinc
plate to be q negative. SO We invert
the Aim on the glass. Thus you see we can
print with this film to read either forward or
backward. Now coat the zinc plate in dark
room with sensitized albumen. dry II. place the
negative over 1t in q close printing frame. bring
it out and expose it to sunlight. then take 1t
into the dark and roll the whole plate with
printers ink. making it all black. Then i'm
merse 1t in water and ell that portion OF the
albumen unaffected BY light will be dissolved
away with the ink thereon, leaving the lines
standing in relief. This is the great secret Of
phUto-relief printing in all its branches. Please
remember the action Of light on the sensitized
albumen makes it insoluble, while that portion
between the lines being unaffected readily dis
solves away, leaving the lines standing In relief
But as yet the lines not high enough to
print sharp and fair, we cut away the blank
space between by etching with acid IS follows:
The plate is first to be vanished on its back
and edges to protect those parts and then it 10
sy~t<~ l. r.
The ink which was rolled upon the plate before
the gelaNne was dissolved away now protects
the lines from the acid by its greasy repulsion.
This plate which show you has been once
etched, but it is not deep enough. Then whv
did We not keep 1t in the acid longer and etch
1t deeper? Because after the acid passes the
protected surface 1t will eat into the sides OF
the lines and destroy them. Now We want to
protect the sides Of the lines can etch
deeper between them, but how can We varnish
Thousands Of little lines not higher than thick
paper and not varnish the spaces between? By
applying finely powdered dry resin, such as
shellac, with the plate slanting one way it banks
up that side Of all the lines. then heat the
plate until the shelac melts and forms
varnsh just where it had lodged and
have vanished one side Of all the standing
lines. Then we cool the plate and turn it on
the opposite edge and apply more dry powder
and again melt 1t. and thus we have vanished
the two sides Of all lines running one way on
the plate. But lines run in all directions. 40 we
must treat the plate In the same manner from
each side edge in order to insure vanishing
both sides Of every line. We cannot varnish
two sides of any line at once because the light
brush or tuft of cotton with which the powder
Is applied would only pile up powder at one
side of line while pulling It away from the
other side. Now we dip the vanished plate a
second time in acid and leave 1t three minutes
for the second biting. Then We again wash and
dry 1t and repeat the four-slded vanishing and
then give 1t final dip in the acid for the last
etching.
THE cUr READY FOR USE.
This second plate has had the three etchings.
but all the broad spaces must be cut still
deeper and it is done mechanically, by thu
routing machine as shown in all this region.
Now the plate is to be fastened upon a block Of
wood like this. to make it type-high and then 1t
lie ready for service and it may be used alone to
print with direct. or it may be bound into q
form with type to make matrix with.
In reproducing anything from an ink print
there Il no hand drawing necessary, because
the type and engravings are already in lines.
Valuable books. which are not copyrighted. and
some books like old copies OF Webs er's Die
tionary, on which the copyright has expired,
are now reproduced by this zinc process, six or
eight pages at one print. without the expense
OF setting type, so that dictionary which used
to cost Sl4 may now be bought for less than
SO. But that is not the latest edition. These
plates, films and prints were kindly loaned to
me by Mr.. Maurice joyce Of this city. and he
has taken pains to show me manv of these de-
tails for your entertainment. He is the inven-
tor and proprietor of the kaolatype process.
which is the first successful method ever used
to make pictures 40 quickly a. to be printed in
connection with type in daily paper 1t first
appeared in illustrating the Washington Critic
in 1877, and it is still the quickest method
known for that kind of work. The steps