Evening star. [volume] (Washington, D.C.) 1854-1972, 1893-09-30
DRAWINGS IN MULTIPLE,
What is Done mt n Funny Little Build
ing Back of the Treasury.

me erect to the eye vas somewhat like
that OF arranging scenery on the stage.
Approaching from the direction of the
Washington Monument, It was difficult to
make out what sort of performance was
being conducted on the high platform at
tached to the small frame building in the
rear of the Treasury Department. Persons
were wheeling about a number of queer
looking frames of large size. Each one was
placed in such a way that the bright sum
rays were reflected from its glass surface
dazzlingly toward the behol1er.
Probably there are COMPARE lively few peo-
pie in Washington who have taken notice
of this building. or who have any notion as
to what sort OF work is lone there. On en-
tering the door, one finds himself confront
ed by spectacle of many great tanks ap-
parently full of chemicals. On the sur.a ce
of these tanks big sheets Of paper are float
ing ana at intervals BUSY workmen take
out the wet sheets and put in others hang
ing the former up to dry. On the paper are
all sorts OF architectural drawings and de-
signs.
One is directed upstairs to the superin-
tendent in charge, Mr.. NacBlair, who ex-
plains that the establishment IS a branch
Of the office of the supervising architect Of
the treasury. Here the plans for Uncle
Sans public buildings are multiplied ly
the aid of photography One reason why
much of such work has to be done IS that
numerous bidders for contracts in the way
OF construction must he supplied with
copies of the drawings. on which they have
to base their estimates as TO cost. &c. OF
course, to reproduce the dra wings hy hand
would be enormously laborious and eXpen-
sive; but the sun does ii compare lively
cheaply and with absolute accuracy. The
only disadvantage OF the celestial work.
man-not intending to refer to him as a
Chinaman, be it understood-s that he fire.
quently goes on strike. sulking behind a
cloud.
Architects all over the world utilize the
suns rays for the purpose of multiplying
their drawings They take a plan Or eieva-
ton. for example, and reproduce it in the
shape of what is called blue print" Thai
is to say. they lay a tracing of it upon a
sheet OF sensitiZed paper ami expose them
to the solar orb. Wherever the sensitive
paper is not protected by the lines of black
ink on the tracings it turns blue, and the
result is sheet with blue background.
on which all the lines of the tracing are
copied in white. In other words, it is a
negative.
But the method practicad at the govern
ment establishment described is much bet
ter. A chemically prepared paper is expos
ed to the sun beneath an ink dra wing on
tracing linen. just as in the case OF the
blue print. But the result is that the lines
appear in light green a white back
ground. Then the sheet is put into an acid
bath, which turns the green lines to black
Thus a positive is obtained from positive
WHICH Is IluCH ElOTe satisfactory. 1t Is in
this work that the frames already spoken
of are used, and on any fine day they NAV
be seen out on the high platform at the
rear of the building. with their glass cover
ed faces toward the sun.
Some of the finest sort Of work with the
camera is done in this little building The
photograph of Mr.. Cleveland which the
President considers the best ever taken of
himself was made here during the early
part of his first administration. The ar
lists of the staff have also made some beau
tiful sun pictures of the principal public
buildings in Washington, which are pre-
scented to cabinet officers and other import
ant official personages. They were en-
ployed to reproduce by photo.rra ply The de-
sign for the worlds fair diploma. The gov
eminent paid 5000 for the original draw
ing. which was done with the brush. For
the purpose of reproducing it by engraving
unmounted photographs of the design We're
required. These, of course, the engravers
could cut up and spoil as much as they
pleased.
So fine and sunshiny day was chosen
and a photograph of great beauty was OBJ
tanned. The glass negative is now kept at
MIR. MacBlair's establishments and is proudly
exhibited, as well 1t may be, as n master
piece of Photographic art The engraving
Of the diploma has been done at the bureau
Of engraving and printing.