



Produced by Chris Curnow, RichardW, and the Online
Distributed Proofreading Team at http://www.pgdp.net (This
file was produced from images generously made available
by The Internet Archive)









 PHOTO-LITHOGRAPHY

 [Illustration]

 BY

 GEORG FRITZ

 _Vice-director of the Court and Imperial State Printing Works at Vienna_

 TRANSLATED BY

 E. J. WALL

 (_Fellow of the Royal Photographic Society_)

 _Author of “The Dictionary of Photography,” “Carbon Printing,” etc._

 [Illustration]

 1895
 LONDON
 DAWBARN AND WARD, LIMITED
 6, FARRINGDON AVENUE, E.C.




THE AUTHOR’S PREFACE.


Photo-lithography, with its many branches and its extended application,
when used direct and also as handmaid for the lithographer and printer
from stone, is, with the exception of phototypy and autotypy, indeed
that process for the preparation of letterpress plates which has done
the most towards making photography useful for the graphic arts, in the
artistic sense as well as from the practical point of view. And in the
near future it will be a great acquisition when it is once generally
recognized that colour plates can be prepared by photographic means
without any considerable amount of manual or artistic help. It is the
more to be wondered at that photo-lithography has not yet found that
extension and general use which it in so high a degree deserves.

I have written this book, impressed with the urgency of stimulating
the propagation of this useful process. In writing I have been careful
to avoid all those details which are for the practical worker of
minor interest—the description of the historical evolution, etc., so
instructive as these must certainly be—so that I have abstained from
many complicated and unintelligible formulæ. I leave this willingly to
a more ready writer. Starting rather from the standpoint of speaking as
a practical worker to practical men, I have recorded all the experience
which I have gained in the course of many years.

Should it occur to me in the future that it was my task to have treated
all photo-lithographic processes, with all their ramifications, in
the most complete manner, I have still the consciousness of having
described as completely as possible the practical processes, and think
that I have thus been useful to many workers, {2} and I dare say with
absolute certainty that only tested and tried formulæ have been noticed
in this book.

With the earnest wish that this book may be received with a fraction
of the goodwill with which I have worked at the writing of the same, I
present it to the technical world.

 GEORG FRITZ.

 Vienna.

       *       *       *       *       *

On receiving this work for review I was greatly struck with the
thoroughly practical manner in which it was written, and thought that
an English translation might be acceptable to the large and ever
increasing class of photo-mechanical workers who might not otherwise
have the opportunity of reading it in the original. I have kept to the
author’s text as close as is consistent with the idiomatic construction
of German.

I am indebted to Messrs. Hazell, Watson and Viney for permission
to undertake the task of translating the work for another firm of
publishers, and I hope the translation may prove as acceptable and
useful to the readers as it has been pleasurable to me to do it.

 E. J. WALL.

 1, Creed Lane,
 London, E.C.

{3}




INTRODUCTION.


1.—_The theory of printing from stone._ He who would study or practise
photo-lithography must first become acquainted with the fundamental
principles on which lithography rests. I find it therefore necessary
to first give in concise form a small treatise on the theory of this
process as well as on the most important materials which are necessary
in the practice of the same.

The theoretical principle of lithography is purely chemical, and is
based principally on the repulsion of water and other substances by
fatty bodies, and the alteration of these greasy bodies by acids. As
the support for this chemical opposition a stone or zinc plate is used,
which are sufficiently porous to allow grease, water, acid, and certain
resinous solutions to penetrate to a certain degree.

The fatty substances which are transferred to the stone by writing,
drawing, or transfer, are autographic ink, lithographic ink, and chalk,
the so-called transfer and photo-lithographic colours. There are also
other substances, which are used especially in photo-lithography, which
do not evidently penetrate the stone and which cannot be considered as
greasy substances, but which, as we shall see later on, have exactly
the same action.

The above-mentioned fatty substances actually penetrate the porous
stone and make it in places suitable to take more printing ink. By
the so-called etching—dilute nitric acid mixed