This artist learned the method of line work for process in a month.]

CANTOR LECTURES.

The ILLUSTRATIONS in this Volume are, for the most part, reproductions
of drawings which--for purposes of study and comparison--are shown by
Mr. Blackburn at his Lectures in Art Schools, enlarged to a scale of 15
to 20 ft.

Students who may be unable to attend these lectures can see some of the
original drawings on application (by letter) to "The Secretary, at Mr.
HENRY BLACKBURN'S STUDIO, 123, Victoria Street, Westminster."

APPENDIX.

1. PHOTO-ZINC PROCESS.--2. GELATINE PROCESS.--3. HALF-TONE.--4.
INTAGLIO PROCESSES.--5. DRAWING MATERIALS.--6. BOOKS FOR STUDENTS.--7.
DECORATIVE PAGES.--8. LIST OF PHOTO-ENGRAVERS.

PHOTO-ZINC PROCESS.

FOR THE REPRODUCTION OF LINE DRAWINGS IN RELIEF, SUITABLE FOR PRINTING
AT THE TYPE PRESS.

DESCRIPTION OF THE PROCESS.--The first stage is to have the drawing
photographed to the size required, and to transfer a print of it on to a
sensitized zinc plate. This print, or photographic image of the drawing
lying upon the zinc plate, is of greasy substance (bichromate of potash
and gelatine), and is afterwards inked up with a roller; the plate is
then immersed in a bath of nitric acid and ether, which cuts away the
parts which were left white upon the paper, and leaves the lines of the
drawing in relief. This "biting in," as it is called, requires
considerable experience and attention, according to the nature of the
drawing. Thus, the lines are turned into metal in a few hours, and the
plate, when mounted on wood to the height of type-letters, is ready to
be printed from, if necessary, at the rate of several thousands an hour.

THE COST of these blocks averages 6d. the square inch where a number are
made at one time, the minimum price being 5/-.

Small book illustrations by this process, by firms who make a specialty
of producing single illustrations, are often charged 9d. the square
inch, with a minimum of 7/6; but the cost should never be more than this
for a single block by the zinc process.

GELATINE PROCESS.

FOR THE REPRODUCTION OF DRAWINGS IN LINE IN RELIEF, SUITABLE FOR
PRINTING AT THE TYPE PRESS.

This is a more delicate and sensitive method of obtaining a relief
block. It is called the "gelatine," or "Gillot" process.

The drawing is photographed to the required size (as before), and the
_negative_ laid upon a glass plate (previously coated with a mixtu