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Full text of "Modern Mechanical Engineering Vol-I"

1

THE   PHOTOGRAPHIC  ROOM                       37

CHAPTER  V
The Photographic Room

Sun Prints.—In the olden days the method of printing was for one of
the apprentices to run up to the roof with the tracing and put it in a flat
printing-frame, similar to that used by the amateur photographer but of
course very much larger, and to leave the sun to do the rest. This method
is only tolerable where the number of prints required in a day is small. In
large offices, not only is someone required to take off prints all day, but a
much more rapid method is necessary. The photographic room has become
a well-equipped and indispensable portion of the drawing office. In an office
employing about twenty-five men, the writer has known 120 large photo-
graphs being taken, dried, and dispatched in one day, including all the neces-
sary indexing, &c. This keeps one man busy the whole day, as quite a number
of the prints are black-and-white ones, which take about six times longer
to print than the usual blue prints, and require considerably more washing.

Equipment of Photograph Room.—Not only must the photographic
room be well equipped with an up-to-date electric printing-frame, but it
should have several large baths for washing, a plentiful supply of water, a
permanent squeegee, a good drying oven, and also a considerable number
of laundry rods for natural drying. A table with a hard wooden top should
be provided, a large steel straight-edge, or better still an automatic grip,
and a deep-cutting knife. Ventilation is highly important, as the drying
oven is generally a gas one. The fumes of the oven are apt to lie about the
room, and the process of natural drying is very slow if a good current of air
is not available.

Procedure for Obtaining Prints.—When prints are wanted, the
section leader wishing them enters up a requisition form, which is printed
in a small manifold book. Alternate leaves of this book are printed perhaps
on pink paper, and have perforations for detaching them. The copy leaves
are unperforated and may be white paper. The ordinary carbon sheet is
used to get the duplicate. A sample page is given herewith.


	JOB No. 531.   Date 11/11/20.
		

	TITLE: Foundation Plans.
		

	DRG. No.   531/87-
		
a
	No. off.
	Sent to
	Kind of Print.

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 Ul
 O
	I
	D.O.
	Blue mounted

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 b
	2
	Jnspr.
	„   thin

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	2
	Owner
	/    Black-and-white \       mounted


	I
	F.S.
	Blue, thick


	I
	E.S.
	»       *»


	I
	W.M.
	„    thin