West Virginia freeman. (Parkersburg, W. Va.) 1881-1886, 1882-10-18
The Blue Process of Copying
TracingS.

| Inv DsuO ANCSc VI NVRS AuS
Tracings.
As we have had several inqui-
ries recently in regard to the best
method of copying tracings by
what is known as the "blue print
ing process" we will give a brief
description of the method en-
ployed by us; we do not say it is
the best, but it certainly is as sim
pie as any other, and has always
given US perfect satisfaction.
The materials required are:
l. A board a little larger than
the tracing to be copied. The draw
ing-board on which the drawing
and tracing are made can be used.
2. Two or three thicknesses Of
flannel or other soft white cloth,
which is to be smoothly tackled to
the above board to form a good
smooth surface, on which to lay the
sensitized paper and tracing while
printing.
8. A plate of common double
thick window glass of good quail
ty, slightly larger than the tracing
which it is wished to copy. The
function of the glas, is to keep the
tracing and sensitized paper close
ly and smoothly pressed together
while printing!
4. The chemicals for sensitizing
the paper. These consist simply
of equal parts, by weight, ofcitrate
of iron and ammonia, and red
prussiate of potash. These can be
obtained at any drug store. The
price should not be over or 10
cents per ounce for each.
5. A stone or yellow glass bottle
to keep the solution Of the above
chemicals in. If there is but lit
tie copying to do, an ordinary glass
bottle will do, and the solution
made fresh whenever it is wanted
for immediate use.
6. A shallow earthen dish in
which to place the solution when
using it. A common dinner-plate
is as good as anything for this pur-
pose.
7. A brush, q soft paste-brush
about 4 inches wide, is the best
thing we know of.
s. Plenty of cold water in which
to wash the copies after they have
been exposed to the sunlight. The
outlet Of an ordinary sink may be
closed, by placing piece Of paper
over it with weight on top to
keep the paper down, and the sink
filled with water, if the sink is
large enough to lay the copy in.
If it is not, it would be better to
make a water-tight box about 5 or
6 inches deep, and 6 inches wide
and longer than the drawing to be
copied.
8. A good quality of white book
paper.
Dissolve the. chemicals in cold
water IN the following proportions !;
| ounce of citrate of iron and am
monia, l ounce of red prussiate Of
potash, s ounces Of water. They
may all be put into bottle togeth-
er and shaken up. Ten minutes
will suffice to dissolve them.
Lay sheet of the paper to be
sensitized on smooth table or
board pour a little of the solution
into the earthen dish or plate, and
apply good even coating of it to
the paper with the brush, then tack
the paper to board by two ada
cent corners, and set it in dark
place to dry one hour is sufficient
for the drying then place its SEN
sitized side up, on the board on
which you have smoothly tackled
the white flannel cloth lay your
tracing which you wish to copy on
top Of il on top of all lay the glass
plate, being careful that paper and
tracing are. both smooth and in per-
feet contact with each other, and
lay the whole thing out in the sun
light. Between eleven and two
o'clock in the summer time. on a
clear day, from 6 to 10 minutes
will be sufficiently long to expose