IMPROVE- MENTS IN PHOTO-MECHANICAL PRINTING, AND IN APPARATUS AND APPLIANCES THEREFOR
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by Walter Bentley Woodbury at the
Office of the Commissioners of Patents, with his Petition, on
the 4th December 1872.
I, WALTER BENTLEY WOODBURY, of Greenhithe, in the County of
Kent, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN PHOTO-MECHANICAL PRINTING, AND IN APPARATUS AND APPLIANCES
THEREFOR," to be as follows:—
These Improvements relate,-
Firstly. To a method of obtaining by photography blocks suitable for
employing with type in the ordinary method of typographic printing,
either from a subject represented by lines as an engraving or wood-cut,.
or from a photograph containing only half tones as a portrait or
landscape from nature or a painting.
Secondly. To improvements in the process known and termed in the
Woodbury Type" by which that process is rendered much
trade
simpler.
Thirdly. To an improved method of producing the same by machinery.
To accomplish the first part of my Invention I proceed as follows :-
Where the subject is in line I make a positive photograph of it (i. e.
positive by transmitted light), and from this I obtain a relief in gelatine

page_text: details of the relief; but in that state it would be useless to print from.
I then proceed as follows:-A shallow metal box is filled with a com-
position of shellac and ashphalte which on warming becomes soft, but
hardens on cooling; this box is placed on a hot plate until the com-
position it contains softens, it is then placed on the lower plate of the
ordinary Woodbury printing press, the foil and relief laid on it, the press
closed and the pressure applied by the under screw. When the com-
position has hardened the tin foil adheres to it and I remove the gelatine
relief from the foil, and use the foil backed mould to print from. In
place of fixing the proofs by alum or other substance of a like nature I
varnish the proofs with an ordinary varnish composed of shellac and
alcohol, which gives the print the effect of a photograph on albuminized
paper at the same time protecting the surface from moisture. I also
sometimes use the composition melted in boxes without the foil as a
printing mould direct, and when sufficient numbers have been printed
the box holding the composition is again heated, and can be used over
and over again. The third part of my Invention consists in an improved
method of printing "Woodbury type" by machinery. This I accomplish
as follows:-Out of a solid block of iron I have turned a cylindrical hole
in which is made to fit very loosely a cylinder of soft metal having a
taper or conical hole through it lengthwise. Between the interior of the
steel block and the soft metal cylinder I insert the gelatine reliefs, then
by. means of a taper or wedge-shaped spindle (roughtened) I drive by
hammering or by pressure the soft metal against the iron cylinder thus
impressing the relief on the outside of the metal cylinder, the taper
spindle at the same time forming a shaft for the cylinder to be used in
the process of printing. I then mount this roller bearing the relief in
vertical slots in a frame having a bed of plate glass on which the paper
rests, the roller resting on the glass by its own weight and being dragged
round by the paper itself, or in place of the glass plate I allow the soft
metal cylinder to lie on another fixed or moveable roller of metal or
glass. The latter may be hollow so as to reduce its temperature in hot
weather by a stream of cold water running through it.