ng._ Cutting the guard lines or bearers off the
electrotype to practically the finished size before blocking or
bevelling.

_26. Blocking._ Fastening the plate on wood base with brads driven
through the metal.

_27. Trimming._ Trimming the wood mounted electrotype to its exact
finished size.

_28. Type-high Machining._ Used for planing the bottom of the wood
base so that the mounted electrotype is of printing press
requirements, i. e., .918" high.

ELECTROTYPING BY THE LEAD MOLD PROCESS

Electrotypes made by the genuine Dr. Albert Lead Mold Process are
always duplicates of fine-screen half-tones or mezzo-tints used for
the highest class of commercial job-work, such as three and four color
process or duo-tone printing on paper with a highly glazed surface.

The largest press used in lead molding will give a maximum pressure of
two thousand tons per square inch on a thirty inch ram hydraulically
operated. The weight of this press is over thirty thousand pounds.

[Illustration]

In the lead mold process the plastic medium used is a soft thin sheet
of what is called "impression lead," .040 inches thick, instead of
wax, and the lead is placed on top of the original to be duplicated,
instead of vice-versa, as in the wax-molding process. No "building-up"
nor "black-leading" is necessary.

In all other respects the consecutive steps towards the completion of
the lead mold plate are identical to those used in the Wax Mold
Process.

ALUMINOTYPES

The age long progress in the development and perfection of
typographical printing surfaces, from the period of Xylographic blocks
on through the successive inventions of individual movable cast-metal
type, stereotyping and electrotyping, by both the wax and lead-molding
processes, reaches its culmination in _Aluminotypes_.

Briefly, it is a method of casting printing plates of aluminum alloy
in molds made from a composition of plaster-of-paris. In its essential
points it is a modern adaptation of the process credited to William
Ged of Edinburgh in 1730 and afterwards modified and improved in the
early 19th century by Earl Stanhope of England.

In practice, the original to be duplicated is placed on a
molding-slab. A molding frame is set upon the slab and enclosing the
original. A special kind of oil is then sprayed on the face of the
original. This is to facilitate the release of the plaster mold so
that it will not "tear" when it is ready to be lifted o