THE CARBORUNDUM P H :! T
A circular describing a new process
for print makers suitable for black
and white or color, with instructions
on the preparation of the ground and
method of printing.
WPA Technical Series
Art"^rcular Ho. 5
September 10, 19<0
FEDERAL WORKS AGENCY
WQRK PROJECTS ADMINISTRATION
Division oT Professional and Service Projects
Washington, D. C.
A1510
A1510
THE GAEBQOTIKjM PHI NT
A1510
FOEBSTORD
The Carborundum print owes its name and its
char net ex to abrasive Carborundum, the commercial
designation of the crystals or carbide of silicon
with which the copper plate is grained. 1' m the
completion of the graining the design is trans¬
ferred through carbon paper to the plate, and its
values developed by scraping and burnishing, end
by the use of abrasives. Wiping-out of ink creates
a further variation of tone.
T'o Carborundum etching is prepared in the same
manner as the Corborundum print, up 'to the stage of
developing the design. In this process the design
is applied with acid-resist stopping-out varnish or
lithographic crayon, and bitten into the -plate by a
nitric acid bath. Control of inking may be employed
as in the Carborundum print.
Specific information regarding tools, materials
and techniques is incorporated in the article which
follows.
F. C, Harrington
Commissioner of
Work Projects
THE CAREORUITPUM PRINT
When the Federal Art Project first introduced the
Carborundum print as a feature of its Print Exliihition
at the Rational Museum on October 7, 1938, artists and
the public expressed immediate interest in the technique
of this medium, which had been developed by a group of
artists in the Department of Fine Prints of the Penn¬
sylvania Federal Art Project.*
In response to this interest, and aware of the range
of possibilities in this medium, the Magazine of Art,
publication of the American Federation of Art, presented
in its issue of November, 1938, a technical account
(Carborundum Tint - A Now Print-Maker's Process).
Since 1938 experiments with this new medium have
been continued and its range of possibilities explored.
This booklet seeks to make available the technical .
information thus developed, in the hope that it will
stimulate creative activity and public appreciation.
The Carborundum print derives its unique tonal
character from the groining of the copper plate with
*The artists who collaborated in- developing the process
are: Dox Thrash, Michael J. Gallagher, and Hubert
Mesibov.
A1510
2.
the minute, diamond-hard crystals of carbide of silicon,
for which the trade name is Carborundum* Yet the lumin¬
ous quality for which Carborundum.prints are noted is
also enhanced by the manipulation of inking, therefore,
the complete-process will be described, even though much
of the information will be familiar.
PREPARATION OP THE PLATE
Polled etching copper, #16 or #18 gauge, with a
highly-"burnishod, mirror-like surface, best serves the
purpose of the artist; but the back of an old etching
plate can also be used. If the copper is purchased
ovcr-sise it may bo- prepared for reduction to desired
dimensions by placing it polished surface upwards, upon
a flat table, the area to be removed extending over the
edge. A metal straight-edge, its under-side covered
with a strip of felt or soft paper, to protect the
copper surface, may then be laid along -the line to be
cut, in alignment with the edge of the table. The
straight-edge should be clamped firmly to the table,,
beyond the edge of the copper, to prevent slipping.
Then, with a knife or other sharp instrument, the copper
should be scored several times along the straight-edge.
Ale 10
3
'The copper should "be reversed, polished side downwards,
again protecting the polished surface, and then again
scored along the same line. Bending the extended area
"bach and forth will separate it. The rough edges and
sharp corners must "be smoothed and rounded, first with
a file, and then with any hard metal tool, in order to
prevent cutting the paper when printing from the plato.
ERAWING...
Table with
plate, knife, FIG. 1
clamps, etc.
The plate should now "bo placed on a perfectly flat
base several inches larger in each direction than the
plate itself. This base should be three or four inches
thick. A block of wood, an old lithographic stone, or
a solid piece of metal will serve the purpose. It is
important that the surface of the supporting base be
quite flat, as any variation of surface v/ill interfere
with an even treatment with the Carborundum grains.
The base, with the plate upon it, should then be set
into a tray deep enough to catch the excess water and
carborundum which will drop from the plate during the
process of preparing its surface. A cloth should be
placed under the base, extending generously around it,
to hold the grains. An old sink is preferable to a tray
if continuous work is contemplated. The sini £~cuid not
he connected to the plumbing, hut should have a. pail
beneath it to catch the water and carborundum grains.*
DEAWIHG- ...
Sink, stand
with plate in it, TIG. 2
ready for graining
Carborundum, used for many commercial purposes, is
obtainable in various grades of fineness. A size which
has been found most satisfactory for this work is #80,
which gives a wide range of values, from s. deep, velvety
black to a light gray tint, and possesses a full ink-holding
surface. However, the finer grades of carborundum grains,
such as #li>0, #160, #130, #220, and even #F arain, which
is exceedingly fine, have been experimented with and have
proved helpful in varying the general tone, either used
singly, or in combinations on the same plate.
The surface of the plate should now be sprinkled freely
with the carborundum grains. When evenly covered, it
should be sprinkled with water until it is well dampened.
However, there should not be any freely flowing water on
the surface.
♦Carborundum clogs ordinary plumbing outlets.
A Irrigator, a flat steel fifteen-pound, disk with a
wooden handle attached vertically to its upper surface,
should now be placed, upon the .plate. If it is not
possible to secure a levi-uator from a lithographic
supply house, a discarded flat iron may be employed as
a legitimate substitute. The levigator should now be
rotated gently over the surface of the plate until the
carborundum is ground into the copper. Actual experience
will teach the time required for this. During this
process, some of the carborundum grains will be displaced,
»)
but they may be collected from the cloth placed beneath
the base and replaced on the plate; or they may be drained
off into the pail and later salvaged. When the graining
process seoms to be developing properly, the plate should
be flushed with water to clean it, and' examined in a
strong light. There may be portions not ovonly grained,
in which caso the pla.te should be returned to its position
on the base, and again covered with carborundum grains.
Repetition of the graining process will effect complete
distribution of the graining. Because the surface of the
copper is not always flat and may have depressed areas
in it, certain spots may scorn difficult to surface.
Crumpled wads of heavy cardboard, placed beneath the plate
A1510
6.
"below the spots to "be worked on, will aid in correcting
these depressions during the graining T>rocess.
Aft- r initial experience, the graining process should
not require more than fifteen minutes. When it is com¬
pleted, it is essential that the plate be washed clean
and free of all loose carborundum particles.
DRAWIHG- ...
Levigator on plate FIG-. 3
showing Carborundum
The plate is now surfaced, and ready for the application
of the design. If it were inked and run through the press
at this stage, it should produce a proof of an all-over
deep, rich, even black. The prepared design should be
transferred to the plate through a piece of carbon paper.
The sketch and the carbon paper may be fastened to the
plate by means of Scotch tope. The tracing should be
made with hard pencil. Since the carbon paper's film
adheres with considerable tenacity to the roughened surfa.ee
of the sketch as in drawing on a plate prepared for etching.
The "present tone of the plate represents its darkest value,
and all lighter values are obtained by reducing the ink-
holding quality of the plate. This may be described as
lowering the "hills" toward the level of the "valleys."
This may "be done with an etcher's scraper or "burnisher,
by lowering the points produced on the plate by the
abrasive. The more the scraping or burnishing, the
less ink will the worked-cn area hold. This process,
when practised sufficiently, will produce the desired
variation in values. The following drawing shows a
greatly enlarged cross-section of the plate and more
fully illustrates the nature of its "hills" and "valleys."
DRAWING- ...
G-reatly enlarged cross-scction
of plato showing area PIG-.. 4
reduced by scraping and
burnishing; also tools used
After the main elements of the design have been
developed through the processes described, a proof should
be pulled for analysis. This proof is usually quite dark
but it affords an opportunity for correction.
PRINTING-
The method of printing a Carborundum print is a simpli¬
fication of the method employed with etchings. The plate
is not heated, for heat would soften the ink. The plate
should be inked richly with etcher's ink, well rubbed in.
Some old tarlatan may be used to wipe away the ink that
the plate will not readily hold. The wipings should he
continued until the design begins to appear. At this
stage a new and fresh piece of tarlatan should be used to
bring out the design more clearly. Another fresh piece
should then be wrapped about the index finger and applied
to wipe out the lighter areas. High lights may be develop¬
ed by working with a charcoal stump of paper dipped in
whiting. The paper for printing should be prepared by
dipping it in water and allowing it to lie between damp-
blotters for some hours or overnight. After the first
print has been taken, the plate should be cleaned with
turpentine. The scraping and burnishing should continue,
until all additional variations of tone are secured.
Emery cloth, wrapped about the index finger, or steel
wool, may be used for variety of effect. Frequent
proofs should be pulled for careful study.
CARBORUNDUM ETCHING
The plate for a Carborundum etching is prepared in the
same manner as for the Carborundum print, and the design
transferred upon it through carbon paper. The design is
then drawn upon the plate with acid-resistant stopping-out
varnish or with lithographic crayon. When the drawing is
completed the plate is immersed in a nitric acid bath.
composed of 60$ acid and 40$ water. The stopping-out with
varnish or crayon is similar to that involved in making an
aquatint. Twenty-five to thirty minutes is usually suffi¬
cient time for biting the plate. It may be printed in the
same manner as a wood-cut, by rolling the ink-roller over
the plate very lightly; or the plate may be wiped with tar¬
latan as for a Carborundum print.
DRAWIIiG ...
Etching Press PIG. 5
COLOR PP.IilTIl'TG
Successful experiments have been undertaken in the use
of color in Carborundum etchings and prints.* It has been
demonstrated that the method of double printing, used by
some printmakers for colored aquatints, could be applied to
the color carborundum etching with very satisfactory results.
The preparation of the plate remains the same for the double
print method and the color (consisting of etching ink thinned
with turpentine to the consistency of thick cream) is broadly
applied to the bitten portions of the plate as before, using
a soft brush. In larger areas where a softening or blending
*The carborundum etching color process was developed by
I&ibert Kesibov, assisted by Michael J. Gallagher.
A1510
10.
of color is wanted, as for clouds in a sky, the color nay he
allowed to settle for a few minutes before being wiped with
a soft rag or the finger to obtain the desired effect. After
a proof is pulled and stored in a damp blotter, the color is
removed from the depressed areas with turpentine and the un-
bitten areas are rolled up in some key color, such as black.
The advantage of this printing method becomes plain at this
point for, if in this rolling up process the ink does happen
to get into the depressed areas, it may be easily removed
without fear of destroying the clarity of color or composition.
The print which has just been pulled is placed ,over the plate
and printed a second time, with great care being taken to main¬
tain an absolutely perfect register. With this second printing
the print is now complete.
Color has also been applied to the regular carborundum print
through using this double print method. All colors for a color
carborundum print must.be somewhat more intense than the final
result desired so as to counteract the fact that the general dis¬
tribution of the key color,over the plate in the second printing
destroys some of .the intensity of the pigments.
When the artist desires to make a number of prints at one
printing and obtain a uniform color throughout his edition,
color prints may be pulled and kept in damp blotters, provided
great care is taken so that the wet colors will not bo trans-
A1510
11.
ferred from one to the other. A more perfect register is
possible because all the printing is done cn one plate.
With these developments of the carborundum printmaking
process, a contribution has been made to art which not only-
pro vide s a greater range than black and white, but opens
another field to the growing number of printmakers who are
becoming increasingly interested in the possibilities of
color prints. The discovery and development of the carborun¬
dum process has provided, an experimental stimulus to all
artists working in this popular field of art expression.
KOQ
P-«09
PITCHER,PAIL AND SINK WITH PLATE READY TO BE GRAINED
FIGURE 2
>409
FIGURE 3
CROSS SECTION OF PLATE
FIGURE 4
CARBORUNDUM
GROUND
SURFACE