THE MENTOR 1918.08.01, No. 160,
Photography

BY PAUL L. ANDERSON

PHOTOGRAPH FROM A DAGUERREOTYPE

ONE

Louis Jacques Mande Daguerre (born 1789,
died 1851), was a great French scene-painter who
experimented for many years trying to find some
way of rendering permanent the image projected by
a lens. J. Nicéphore Niépce was engaged in the same research,
and from 1829 until the death of Niépce in 1833 the two worked
together, but it was not until some years
after the latter date that Daguerre discovered
the process that bears his name.
This process may be briefly described as
follows: a highly polished and perfectly
clean silver plate is rendered sensitive to
light by the formation of a deposit of silver
iodide on the surface, this being accomplished
by exposing the plate—of course
in the dark—for some minutes to the
vapor of iodine. When the plate has assumed
a uniform golden-brown color it is
placed in the camera and the exposure is
made, the light projected by the lens
causing a chemical change to take place in
the silver iodide. The image thus obtained
is very weak, and in order to strengthen it
the plate is exposed for some minutes to
the vapor of mercury. It is subsequently
fixed, or rendered permanent, by bathing
with a solution of sodium thiosulphate
(ordinarily known to photographers as
“hypo”). This dissolves the silver compounds
that were not affected by light.
In some cases the picture is still further
strengthened by treating it with chloride
of gold. This not only increases the
vigor of the image but at the same time
improves its stability, so that it is less
likely to fade as the result of atmospheric
action or exposure to light. The
effect of the chloride of gold is literally
to gold-plate the image. As the surface of
the completed daguerreotype is very sensitive
to any mechanical action, it must
be protected by glass. A mere touch of
the finger leaves an irremediable scratch.

The daguerreotype was at one time very
popular for portraiture, but the process
has certain drawbacks that have caused it
to be superseded by improved methods.
Among these drawbacks are the following:
The exposures required are rather long; it
is impossible to make duplicates—a separate
exposure must be made for each picture;
the picture must be held at a certain
angle to make it visible, and the
process is rather expensive and laborious
to work. Nevertheless, exquisite effects
may be obtained in daguerreotype; the
writer has seen pictures of this kind which
for sheer beauty yield to none of the modern
printing mediums.

The decadence of the daguerreotype is
to be regretted for at least one reason,—the
man who elected to work in that medium
was necessarily at least a craftsman,
whereas at the present time many photographers
are neither artists nor craftsmen,
but merely mechanics of only fair skill.
Photography has been brought to such a
state of perfection that good technical
results may be obtained by persons that
work by rote and know absolutely nothing
of the principles underlying the craft.
This lack of training and enthusiasm for
the work must evidently be reflected in
the results obtained.

There are few forms of portraiture art
that equal in beauty choice early examples
of daguerreotype photography. They
have the exquisite delicacy, softness and
individual charm of the best miniature
portraits. Good old daguerreotypes are
treasured possessions in the homes of
many families—and rightly so, for they
combine a fine quality of art with a gentle
personal appeal.

WRITTEN FOR THE MENTOR BY PAUL L. ANDERSON
ILLUSTRATION FOR THE MENTOR. VOL. 6, No. 12, SERIAL No. 160
COPYRIGHT, 1918, BY THE MENTOR ASSOCIATION, INC.

FROM A PRINT BY ALVIN LANGDON COBURN

SELF-PORTRAIT PHOTOGRAPH—By D. O. Hill

TWO

David Octavius Hill (born 1802, died 1870),
was a Scotch painter who conceived the idea of
producing a great historical picture representing
the Disruption of the Church of Scotland. This
work involved painting some four or five hundred portraits,
and Hill, despairing of obtaining satisfactory sittings from
so many persons, turned to the newly discovered
art of photography to furnish the
portraits he needed, with the idea of using
the photographs as a guide in painting.
Hill used the calotype process, invented
by Fox Talbot, which rendered a piece
of paper sensitive to light by coating it
with iodide of silver. When it was exposed
in the camera and developed, a negative
resulted, and positive prints were made
from this negative in the same medium.

Hill became so much interested in photography
that he worked with it for several
years, to the neglect of his painting.
During those years he produced photographic
portraits which have certainly
never been surpassed, and which some
people think have never been equalled.
The exposures necessary were very long—four
or five minutes in bright sunlight.
This fact lends a great deal of beauty
to the results, for there is no doubt that
full sunlight gives effects that cannot be
obtained in any other way, and these
may be of surpassing beauty, provided
the photographer is skilful enough to
manage his apparatus and pose the sitter
properly. It is regrettable that so many
photographers of the present day shun
out-door portraiture, for there is unquestionably
a great opportunity in that class
of work. The claim of some photographers
that out-door light is not satisfactory for
portraiture is refuted by Hill’s results.

Hill was not a great painter. His
works in that medium are well-nigh forgotten,
but he was unquestionably a man
of great sensitiveness, who possessed the
quality of psychic insight so necessary to
a portrait worker. It is the estimate of
an authority that, though he could never
be compared with the great masters of
portraiture, Rembrandt and Velasquez,
nevertheless his works are entitled to a
place in the second rank.

Hill was especially fortunate in his sitters,
for the men and women that he
photographed were persons whom it would
be difficult to render commonplace in
appearance, among them being Christopher
North (Professor John Wilson), J. G.
Lockhart, Lady Ruthven, Robert Haldane,
William Henning, Mrs. Anna Brownell
Jameson, and others of equal note in
Great Britain.

The paper negatives made by Hill are
carefully preserved. The writer is fortunate
in the possession of prints from
two of these negatives. The reproduction
shown herewith, a gum-platinum plate
made and given to him by Alvin
Langdon Coburn, is from one of them.
Much of the beauty of this example of
Hill’s work is due to modern printing
methods, but the quality in this negative,
brought out in the print, proves undeniably
that Hill merits recognition as a
master of portraiture.

WRITTEN FOR THE MENTOR BY PAUL L. ANDERSON
ILLUSTRATION FOR THE MENTOR. VOL. 6, No. 12, SERIAL No. 160
COPYRIGHT, 1918, BY THE MENTOR ASSOCIATION, INC.

THREE

Photography has made possible many discoveries
of tremendous importance in the realm of astronomy
by revealing the existence of stars too faint—because
of their small size or great distance—to be
seen by the eye. This is one of the most conspicuous ways
in which the sensitive plate has been an aid to the
scientist. A device for carrying a photographic
plate is attached to a telescope
and the plate exposed to the image projected
by the telescope for a prolonged
period. This may, in fact, amount to
several hours; exposures are sometimes
partly completed one night and finished
the next, a comparatively small area of
the heavens being chosen for investigation
at one time. On development of the plate
the stars are counted and compared with
existing charts of the area in question.
Of course this method requires that the
telescope move with the same angular velocity
as that of the earth’s rotation, so
that the image of each star may remain in
precisely the same position on the plate
during the entire time of exposure. Otherwise
the star would be represented as a
trail of light, the slightest variation in the
speed of rotation being sufficient to cause
blurring of the image. It is apparent
that the clockwork employed for driving
the telescope must be a marvel of accuracy.

The power which this method possesses
of revealing hitherto undiscovered stars
depends on a curious fact. If an observer
looks into the eye-piece of a telescope he
can discern only those heavenly bodies
that send to the earth a certain minimum
of light; but when a photographic plate is
exposed for long periods there is a cumulative
effect of light on the sensitive emulsion.
That is, the long-continued impact
of the light rays causes, little by little, a
gradual change in the constitution of the
sensitive silver salt. The action thus piles
up, so to speak, and records light that is
far below the visible minimum.

The photographic plate has not only
aided discoveries in the vast realms
of interstellar space, but has also revealed
to us things so exceedingly minute
that no other method of observation could
bring them within the range of our perceptions.

WRITTEN FOR THE MENTOR BY PAUL L. ANDERSON
ILLUSTRATION FOR THE MENTOR. VOL. 6, No. 12, SERIAL No. 160
COPYRIGHT, 1918, BY THE MENTOR ASSOCIATION, INC.

BY PAUL L. ANDERSON

PORTRAIT—By the Bromoil Process

FOUR

In the bromoil process, the first step is to make a
bromide enlargement. The negative from which a
print is to be made is placed in an apparatus resembling
the familiar stereopticon and an enlarged image
is projected on a piece of bromide paper, or paper that has
been coated with an emulsion similar to that used for plates.
After the paper has been exposed to the
image it is developed, fixed and washed,
the result being a large positive print of
the original small negative. Often this
print is allowed to remain as it is, and it is
then known as a bromide enlargement, or,
simply, an enlargement; sometimes the
worker converts it into a bromoil.

The image in an enlargement consists of
metallic silver in a film of gelatine, the
gradations of the picture resulting from the
varying thicknesses of the silver image.
The first step toward changing this to a
bromoil is to treat it with certain chemicals
that bleach out the silver image and
at the same time harden the gelatine in
proportion to the amount of silver present.
The bleached print is then soaked in warm
water, and the high-lights of the picture,
where the gelatine is least hardened, absorb
the water freely, the half-tones less
so, and the shadows least of all. An oily
ink, then dabbed on the print with a
brush, adheres freely in the shadows,
less freely in the half-tones, and least of
all in the lights, being repelled by the
water in the film. The final result is a
print in which the image is formed by
varying thickness of ink, which, of course,
may be of any color.

The advantages of bromoil over bromide
are numerous. In the first place, a bromide
print cannot be regarded as absolutely
permanent, but a bromoil may be.
Next, the color of a bromide print is
limited to black and varying shades of
brown, unless chemical toning is resorted
to, which still further reduces the stability
of the image. But a bromoil may be of
almost any color, and, indeed, of different
colors in different portions of the picture.
The greatest advantage of the bromoil
process, however, lies in the fact that as
much or as little ink as may be desired can
be put on any given area. By varying
the consistency of the ink it can be made
to adhere more or less freely. By modifying
the brush action it can be placed on the
print or omitted from it, and can even,
at times, be removed after being deposited
on the paper. It will be seen that the
artist has complete control over the gradations,
and to some extent, also, over the
outlines of the picture. He can therefore
make the process respond to his desire for
artistic expression to an extent not possible
with any other photographic printing
medium, even the superficial texture of the
image being largely under the worker’s
control.

A variant of bromoil is the oil process,
though it would be more correct to put it
the other way about, the latter process
being the older of the two. A sheet of paper
is coated with gelatine alone, this being
rendered sensitive to light by means of
certain chemicals and then printed under
a negative. The effect is to render the
gelatine hard in proportion to the amount
of light-action, that is, hardest in the
shadows, less so in the half-tones, and least
of all in the lights. The print is then
washed to remove the excess of sensitizer,
and soaked in warm water; the subsequent
operations are the same as in bromoil.
Oil is superior to bromoil in being slightly
easier to manipulate and in not requiring
a dark-room, but it is inferior in that it
demands either daylight or a powerful artificial
light for printing. Furthermore, a
negative the size of the finished print is
necessary, whereas with bromoil, large
prints can be made from small negatives.

Oil and bromoil have the drawback of
not being very rapid to work, three or
four 11×14 bromoils representing a good
day’s work for a careful manipulator, but
they are by far the most satisfactory of
all photographic printing mediums when
the desire is for artistic expression.

WRITTEN FOR THE MENTOR BY PAUL L. ANDERSON
ILLUSTRATION FOR THE MENTOR. VOL. 6, No. 12, SERIAL No. 160
COPYRIGHT, 1918, BY THE MENTOR ASSOCIATION, INC.

PHOTOGRAPH BY PAUL L. ANDERSON

THE LAKE, WINTER—Nature Photography

FIVE

The accompanying photograph entitled “The Lake,
Winter,” illustrates admirably the use of the soft-focus
lens. It is also of interest as showing the
advantages sometimes to be gained from the intentional
use of defects. The normal human eye is unsurpassed
for the purpose for which it is designed; it is difficult to
imagine an organ more perfect in this
respect. The eye automatically, and almost
instantaneously, adjusts itself for
near or distant objects and for varying
intensities of light, and has, moreover, a
field of view of nearly 180 degrees—almost
a complete half-circle. Nevertheless, it
has two defects that tend to impair the
accuracy of vision, namely, chromatic and
spherical aberration. Chromatic aberration
is the inability to focus simultaneously on
two or more of the primary colors (it is this
defect in the eye that causes red letters to
seem to stand out from a blue or green
background, a trick sometimes used in poster
work). Spherical aberration is the inability
to bring to a focus the rays of light
that pass through the lens near the margins
at the same time as those that pass through
near the center. For these reasons—and, in
lesser degree, some others—the eye cannot
see sharp lines, and a lens that gives
sharp definition to the edges of objects
produces results that are esthetically unpleasing,
because foreign to our experience.
The soft-focus lens—of which there are
numerous makes—is so designed that it
possesses the errors that are normal to
the eye, and therefore—if the characteristic
softness of definition is not over-done
by a too enthusiastic worker—gives results
having an agreeable vagueness of
outline. At one time the qualities of this
type of lens were over-worked, the results
being so excessively diffused that, as one
writer said of a print, “it was impossible to
tell whether it was a ‘Portrait of a Lady’ or
a ‘Water-Spout in the Gulf Stream.’” But
for some years past the pendulum has been
swinging the other way, and photographers
in general (it must be understood that this
refers only to artistic workers, not scientists)
are now using the unconnected lens so as
to secure as nearly as possible the quality
characteristic of the normal eye with, perhaps,
a slight exaggeration for the sake of
suggestion, and as a stimulus to the imagination.

WRITTEN FOR THE MENTOR BY PAUL L. ANDERSON
ILLUSTRATION FOR THE MENTOR. VOL. 6, No. 12, SERIAL No. 160
COPYRIGHT, 1918, BY THE MENTOR ASSOCIATION, INC.

PHOTOGRAPH BY KARL STRUSS, BY COURTESY OF HARPER’S BAZAAR.

PHOTOGRAPH ILLUSTRATION FOR A STORY

SIX

A phase of photography that has a very broad scope is
motion-picture work, the mechanics of which depend
on this fact: If an object is looked at for a time and is
suddenly removed from before the eye, the eye continues
to see it for an appreciable time after its removal. This
phenomenon is called “persistence of vision.” A motion-picture
camera is so arranged that a long strip of
film can be drawn past the lens in a series
of jerks, the shutter being opened to permit
the image projected by the lens to fall
on the film during the period that the latter
is at rest; the film is drawn on to the
next position while the shutter is closed.
Naturally, an object moving before the
lens will move slightly during the interval
between exposures, so the film, when
developed, shows a consecutive series of
photographs of the object in slightly different
positions. A positive print is made
from this series of negatives on a similar
strip of film. This is projected by means
of an apparatus something like the familiar
magic lantern or stereopticon, but so arranged
that this film may be drawn along
in jerks. Each photograph is shown for
a fraction of a second, and is replaced,
during the time that the shutter is closed,
by one showing a slightly later phase of
the motion. Because of the persistence of
vision the eye blends these successive photographs
into one apparently continuous
motion. It will be seen that the term
“moving pictures” is really a misnomer,
since the pictures on the screen do not
move, but remain perfectly stationary
during the time that they are seen. By
taking the pictures rapidly and projecting
them slowly the apparent motion
may be slowed down, so that a rifle bullet
may take three or four minutes to travel
across a screen space of as many feet.
By taking them at wide intervals and
projecting rapidly the motion may be
speeded up, and a plant may seem to grow
from a seedling to maturity in a few minutes.
The ordinary taking and projecting
speed is sixteen pictures per second, experiment
having shown that this is the
least number that the eye will blend satisfactorily.
Since each picture is one inch
wide by three-quarters of an inch high—in
the film—it is evident that each second of
time represents one foot of film. The
writer has seen a rather elaborately staged
photo-play that required an hour and
forty minutes for projection; a simple
calculation shows that this involved 6,000
feet of positive film—a little over a mile.
The length of the negative film was undoubtedly
more, on account of retakes,
cuts, and so on. An expenditure of five or
six hundred dollars for film, however, is
but a small item in the cost of producing
an elaborate photo-play, for the actors receive
large salaries—though not so large
as the press-agents would have us believe—and
the cost of scenery is great. The
production of photo-plays is nevertheless a
profitable industry, as may be understood
from the fact that the average daily attendance
in this country is estimated at
about twelve million. Assuming that each
spectator pays only ten cents, this represents
an intake of $1,200,000 daily and,
as is well known, the prices of admission
in many theatres range from 25 cents up
to $1.00 and more. The artistic possibilities
of the motion-picture play are obviously
limited—it can never hope to rise to the
emotional heights of the legitimate drama—but
they are none the less considerable.
It is to be regretted that the motion
picture industry is at present so much in
the hands of producers who pander to the
coarser instincts of the public, through sensationalism
and slap-stick farce; who are
often indifferent to detail—the writer has
seen a cow-puncher represented as wearing
his six-shooter butt-foremost; who treat
the author’s work according to their own
ideas. A well-known author remarked, on
seeing the screen version of one of her
books: “If I hadn’t been fairly familiar
with the story I wouldn’t have known
what it was all about.” In general, firms
seem to be more concerned with getting
the public’s money than with producing
really artistic results. The writer once
saw a photo-play version of a fairly well-known
book, in which the producer had
changed an elderly, gray-haired, quiet,
experienced cattleman into a cheap imitation
of a Bret Harte gambler of thirty
years of age, the purpose of this metamorphosis
being to transform a noble and self-sacrificing
affection into a piece of gaudy
sensationalism. Such tactics cannot fail to
displease thinking people, but there are,
fortunately, producers to whom these remarks
do not apply—really conscientious
men of high ideals, and signs are not wanting
of an improvement in this regard. The
motion picture, in worthy hands, can be
made an educational medium of great
value, not only in the dramatic art but in
many other ways. Films frequently show
scenes of historical interest, life in foreign
lands, industries. Scientific subjects are
treated, such as the peristaltic movements
of the intestines and the action of the
heart, photographed by means of the
X-ray; also the life cycle of micro-organisms,
the microscope being used in this
case—and many other activities of life.
Among the most interesting of these films
are those produced by the Williamson
brothers, showing sea life, though mechanical
difficulties have so far prevented the
photographing of the most interesting phase
of marine life, that of the extreme depths.

WRITTEN FOR THE MENTOR BY PAUL L. ANDERSON
ILLUSTRATION FOR THE MENTOR. VOL. 6, No. 12, SERIAL No. 160
COPYRIGHT, 1918, BY THE MENTOR ASSOCIATION, INC.

THE STORY OF
PHOTOGRAPHY

By PAUL L. ANDERSON

Artist Photographer, Author of “Pictorial Photography”

A DAGUERREOTYPE

Entered as second-class matter March 10, 1913, at the postoffice at New York, N. Y., under the act of March 3, 1879. Copyright,
1918, by The Mentor Association, Inc.

Numerous investigators, Daguerre, Niépce, Fox Talbot,
and others, have been credited with the discovery of photography,
but the fact seems to be that these, and many more,
merely contributed, each in his turn, some portion of the total
that goes to make up the art as it now stands. Photography
means, literally, “light-writing,” the name being derived from
two Greek words, phos, light, and graphein, to write. The practice of
photography depends primarily on the fact that certain chemical compounds
are changed into other compounds by the action of light. Another
fact is closely allied with this, namely, that a suitably constructed lens of
glass or other transparent material, or a fine needle-hole used instead of
a lens, will project the image of objects placed in front of it. A camera,
then, consists of a light-tight box having at one end an arrangement for
holding a lens or a card with a needle-hole in it, and at the other end a
device for holding some light-sensitive chemical to receive the image
projected by the lens. In modern practice this light-sensitive chemical
is almost always bromide of silver or a mixture of the bromide with
other silver compounds, these chemicals being held in an emulsion of
gelatine. When the gelatine emulsion is coated in a thin film on a sheet
of glass the result is known as a dry-plate, or, simply, a plate. When it is
coated on a strip of celluloid wound on rollers
so that successive portions may be exposed
to light, it is called a roll film, and when it
is coated on separate sheets of celluloid,
arranged like a pad, to be exposed successively,
it is called a film pack. A similar
emulsion coated on paper gives bromide or
gas-light paper, which, as will be seen later,
is used for making prints. At one time wet
collodion plates were generally used, a sheet
of glass being coated with collodion and sensitized
by bathing it with iodide of silver.
The exposure was made before the plate
dried; but these plates were inconvenient
to handle and have been almost entirely
superseded by the gelatine dry plate. The
prepared plate, of whatever type it may
be, is placed in the camera and exposed
for a longer or shorter time, depending on
circumstances, to the light projected by the
lens, but no image is visible after exposure, (unless, indeed, the exposure
has been tremendously excessive,) and the plate must be developed.

From a platinum print by Gertrude Käsebier

“BLESSED ART THOU AMONG WOMEN”

Portrait Photograph

From a photograph by Paul L. Anderson

A COUNTRY STATION MASTER

Portrait Photograph

There are about fifty different reducing agents on the market; most of
them are derived from coal-tar, though
some are made from nut-galls, lichens,
and other substances. The developer
consists of a solution in water of one
or more of these reducing agents, with
other chemicals to control the action,
the exposed plate being bathed in this
solution, either in the dark or in a
light to which the plate is not sensitive.
Wherever light has acted on the
silver salts the developer causes metallic
silver to be deposited in proportion
to the amount of light-action, so that
on holding the developed plate up to
the light a dense deposit is seen in
those parts representing the brightest
portions of the subject, while the shadows
of the original are represented
by thin areas, and the half-tones by
deposits of intermediate density. For
this reason the developed plate is
called a negative. The plate is then bathed in a solution of sodium
thiosulphate (generally called “hypo”), which dissolves the unaffected
silver salt but does not affect the metallic silver—or at least does so only
very slowly. Next, the plate is washed in water to remove all unnecessary
chemicals, and is dried. The ordinary plate is sensitive only to
ultra-violet (invisible) and violet light, so it cannot render truthfully
any subject having color, but by the addition of certain aniline dyes to
the emulsion it may be rendered sensitive to green in addition to violet
and ultra-violet; it is then described as orthochromatic (“right-colored”)
or isochromatic (“equally-colored”).
Still other dyes extend the sensitiveness
to include not only ultra-violet
but also the entire visible
spectrum; such a plate is called pan-chromatic
(“all-colored”).

From a photograph by Paul L. Anderson

A PORTRAIT PHOTOGRAPH

Printing the Photograph

The finished negative, when dry,
must of course be printed, and there
are many printing mediums available.
The carbon process gives an image in
lamp-black or some earth pigment,
bound up in a film of gelatine; the
gum-pigment process gives an image
similar to that of carbon, the binder
in this case being gum arabic; the
platinum process gives an image of
black metallic platinum direct on the
paper support. Other processes give
different effects, one of the most
valuable to the pictorial worker being
gum-platinum, in which a completed
platinum print is coated with a gum-pigment film and printed under the
negative a second time, the final result being a gum-pigment image superposed
on the platinum image. Of all printing mediums the one that has
most intrinsic beauty, and is at the same time most capable of rendering
satisfactorily the gradations of the negative, is probably platinum, so this
is most used by pictorial workers. But, since it is expensive and requires
daylight or strong artificial light for printing, nearly all commercial
workers prefer the somewhat less beautiful and less permanent, but
more convenient, gas-light paper, so-called because it can be manipulated
entirely by gas-light, neither daylight nor a dark-room being required.
This medium consists of paper that has been coated with an emulsion
somewhat similar to that used for plates, but requiring much longer
exposure. The negative is placed in an appliance that holds it in close
contact with the paper,
then a sheet of paper is
put in, and an exposure
of a few seconds is
given. Obviously, the
paper receives most
light under the thin parts
of the negative and less
under the denser portions,
so that when the
print is developed, fixed,
washed and dried the
resulting picture is light
where the original subject
was light, dark
where that was dark,
and show intermediate gradations where these existed in the original.

Photograph by Karl Struss

CAPRI, ITALY

From a bromoil transfer by Charles Kendall

THE SHADOW OF A SIGN

For purposes of reproduction two processes depending on photography
have almost entirely superseded the older methods of etching and wood
engraving. These photo-mechanical processes, as they are called, are
far more rapid and much cheaper, and are, in addition, more accurate.
In photo-gravure the photographic image—copied by photographing the
original—is transferred to a copper plate and the plate is automatically
etched in an acid bath to varying depths, depending on the depth of shadow
in the original. This plate is then inked all over, the ink being worked
into the depressions in the copper, and the surface ink wiped off. A
sheet of paper is brought into contact with the plate under heavy
pressure, and, being forced into the hollows of the copper and taking up
the ink from them, a print results.
In the less beautiful
but cheaper and more rapid
half-tone process the copy is
made through a cross-ruled
glass screen, the image being
thus broken up into a series
of dots. The image so obtained
is transferred to a zinc
plate, which is etched in an
acid bath or with an acid
spray. The dots serve to protect
the zinc from the action
of the acid.[A] The finished plate
shows an image consisting of
dots with hollows between
them, the dots being large and near together in the shadows, small and
far apart in the lights. This plate is inked with a roller, and a sheet of
paper, lightly pressed against it, takes up the ink to form a print.
Thus it will be seen that photo-gravure is an intaglio (cut-in)
process, and half-tone a surface-printing process.

Photographic Illustrations

From a platinum print by W. E. Macnaughton

SCENE ON THE CONNECTICUT RIVER

Photography has not only superseded manual processes for reproduction,
but has also largely replaced them for purposes of illustration.
Practically all news illustrations are now made by photography, which is
also extensively used for advertising work. To a less extent it is employed
for fiction illustration, admirable
work having been done
in this field by Clarence H.
White, Karl Struss, and Lejaren
à Hiller. It does not,
however, seem probable that
photography will ever entirely
replace draughtsmanship for
the illustration of fiction, since
the very strength of the
camera,—that is, its surpassing
power of rendering accurately
the outlines and
gradations of natural objects,—operates
as a severe limitation
in the case of original,
imaginative work. It is
difficult to conceive of
“The Fall of the House
of Usher” or “The
Rime of the Ancient
Mariner” being satisfactorily
illustrated by
photography, and if, for
instance, “Le Morte d’Arthur” were made a
photographic subject,
the cost of models, costumes
and scenery
would probably be excessive.

From a carbon print by H. Y. Sümmons

“THE STYGIAN SHORE”

Despite the limitations
of the camera as
regards imaginative
work there is a small
but devoted band of photographers who
use the camera as a means of artistic expression,
and these men and women have
produced some wonderfully fine results that
fulfil the definition of art: “A means of
arousing an emotion in the spectator.” In
the last analysis, however, it will be found
that such results are due to one of two
methods of approach: either the careful
selection of an unusual natural effect, or the
use of one of the so-called “control processes”—that
is, printing mediums that
allow the worker to modify at will either
the outlines or the gradations of the negative,
or both. In the former case, however,
the photographer cannot be regarded as
more than an exceptionally sensitive and
perceptive craftsman, and in the latter instance the camera user, of
course, ceases to be a photographer and becomes a creative artist, using
photography merely as a basis on which to construct an imaginative
result. The possibilities of this second method of work have not yet
been fully explored; they appear to be limitless.

The Precision of Photography

Photograph by Struss

AFTERNOON SUN

The Biltmore, New York

Photograph by Struss

A MISTY DAY

Chatham Square, New York

Photograph by Struss

SUNSHINE AND SHADOW

Park Row, New York

Photograph by Struss

SUNLIGHT ON SURF

The literalness of photography, which prevents its ever competing
with etching or painting in imaginative art, makes it of inestimable value
in certain realms, and scientists of all sorts, astronomers, physicists, physicians,
pathologists,
as well as
architects, building
contractors,
business men,
who wish a precise
and accurate
record of
any object, recognize
the value
of the camera.
Photographs are
often admitted
as legal evidence
in court. It is
impossible to
overstate the
value of the
dry-plate to the surgeon, since the X-ray, generated
by passing an electric discharge through
a glass tube from which most of the air has
been exhausted, penetrates many objects
that are opaque to ordinary light, and,
though invisible to the eye, nevertheless
affect a photographic plate, thus making
possible a precise diagnosis of fractured
bones, gun-shot wounds, digestive disturbances,
and many other pathological conditions
in which diagnosis without a radiograph
would be mere guesswork.

In portraiture, photography is superior
to any other graphic art, since the camera
worker can, by judicious selection of lighting,
pose and facial expression, render the
character of the sitter quite as well as the
draughtsman, this being the final test in portrait work, though it must
be admitted that few portrait photographers meet this requirement.

Microphotography

By Paul L. Anderson

PHOTOGRAPH TAKEN IN A SNOWSTORM

New York

The human eye and mind are, from a mechanical point of view, but
imperfect instruments. Admirably as they serve the purpose for which
they are designed, it is nevertheless impossible for them to observe with
absolute accuracy. The camera, however, has no such limitations; its
observations are accurate and its records
unquestionable, so long as no definite
effort is made to impair their exactness.
For this reason photography is used not
only in astronomy but in many other
branches of science, among its most important
uses being the making of records
of microscopic objects.

A device carrying a photographic
plate is attached to the eye-piece of a
microscope; the plate being exposed
affords, on development, a precise record
of the subject under observation. It may
be noted that in this case, as in astronomical
photography, no camera lens is
required; the microscope, like the telescope,
projects an aërial image which is
impressed on the plate. It thus becomes
possible for the microscopist to study at
leisure a photograph of the object that
was in the field of the microscope,
and thereby eliminate
eye-strain and minimize the
likelihood of overlooking any
feature of interest. It is further
possible to make lantern-slides
from the negative so
obtained. A lecturer by this
means is enabled to show the
photograph to a large group of
individuals simultaneously.

Photograph by Struss

By courtesy of Cleveland Metal Products Co.

ADVERTISING ILLUSTRATION

An example of commercial photography

THUMB-PRINT ON DARK WOOD

Finger-prints are made visible by dusting
with a fine powder, and are photographed
with a special detective camera

Though the photographic
plate thus extends the usefulness
of the microscope, this is
not the limit of its value in this
respect. Light is transmitted
by waves, similar in some ways
to waves in water, the light
waves being disturbances of the light-bearing ether, an invisible, imponderable
substance of zero density and infinite elasticity, which pervades
all matter. (It must be understood that the ether has never been observed
nor its actual existence proven; it is, however, a necessary assumption
for the satisfactory explanation of the observed phenomena of light, so
far as our present knowledge extends.) The distance from the crest of
one wave to the crest of the next is known as the wave length, the lengths
of the various light waves having actually been measured. The human
eye is sensitive only to waves between about four-ten-thousandths and
seven-ten-thousandths of a millimeter in length, a millimeter being about
one-twenty-fifth of an inch, and an object is invisible in the microscope
if its diameter is less than half the wave length
of the light by which it is illuminated, since in
that case the light waves bend around the
object and meet on the other side. We cannot,
therefore, see objects whose diameter is less than
about two-ten-thousandths of a millimeter. But
the photographic plate is sensitive to shorter
waves than the eye; these waves are known as
the ultra-violet. By illuminating the microscope
stage with ultra-violet light it therefore becomes
possible to photograph objects so small
that they must forever remain invisible to the
naked eye, unless, indeed, the progress of human
evolution brings with it increased sensitiveness
to the shorter wave lengths. In this connection
it is interesting to note that there are organisms
so small that they cannot be made apparent to
us even by photography, though we are made aware of their existence
by inductive reasoning from their observed effects.

NEWSPAPER ILLUSTRATION

Enlarged to show half-tone screen

In the case of some objects, a fuller knowledge of their character is
gained if they are examined in a manner somewhat different from that
usually adopted. One of the photographs given herewith shows the effect
obtained by what is known as “dark ground illumination.” Ordinarily,
the light by which a microscopic object is examined passes through the
slide, so that an opaque object is really seen only as a silhouette, but in
dark ground illumination an opaque background is placed behind the
object, and the light is allowed to fall on it from the sides. The object
is thus made visible by the light that is
refracted (that is, bent) into the lens of
the microscope. In the present instance
the effect seen by looking into the eye-piece
was wonderfully beautiful, the
crystals glowing with a brilliant yellow
light against an intensely black ground.

Radiography

Some persons object to the inclusion
of radiography as a branch of photography,
since no camera or lens is used,
but “photography” means, literally,
“light-writing,” and radiography is precisely
this.

If the air be nearly exhausted from a
glass tube, so that a high vacuum exists
therein, and it be then sealed up, a current
of electricity may be sent through
the remaining air, setting up ether
vibrations that pass out from the tube.
These ether waves have the power of passing through many substances
that are opaque to visible light, the X-rays, as they are termed, being
totally invisible, though light waves to which the eye is sensitive are set
up at the same time within the tube. Many persons confuse the greenish
light from an X-ray tube with the X-rays, but the two are actually entirely
different manifestations. The X-rays, though invisible to the eye, are
nevertheless able to affect a photographic plate strongly, so that photographs
may be made through solid objects. For example, if a sensitive
plate be laid on a table and the arm or the hand placed on it, and an
X-ray tube is brought near the arm, a photograph results in which the
bone is represented as a dark area and the flesh around it as lighter, this
being, of course, simply a shadow picture. This affords an intensely valuable
aid to diagnosis, and a good surgeon will, if possible, first radiograph
a fractured bone before setting it, unless the circumstances are very
exceptional. The value of
radiography is not, however,
confined to fractures,
but extends to wounds (it
is of great help in locating
metallic fragments or other
foreign bodies in a wound),
to many intestinal disorders,
and to the diagnosis
of other diseased conditions.

STRIP OF MOTION-PICTURE FILM

Actual size. The photography consumed
five-eighths of a second, or
just long enough for the subject
to turn her head

By courtesy of W. Faitoute Munn

MICROPHOTOGRAPH OF CRYSTALS
OF BRUCINE SULPHATE

(A) By transmitted light

(B) With dark-ground illumination

Though not strictly bearing
on photography, it is interesting
to note that the X-rays,
like the “gamma rays”
(γ-rays) of radium, are in
reality ether vibrations of
very short wave length, and
like the shorter waves (the
ultra-violet) in sunlight,
possess curative powers in
some skin disorders and
also the power of causing
terrible burns. Sunburn
does not result from exposure either to visible
sunlight or to the heat of the sun, but to the
ultra-violet rays; and an X-ray burn is identical
with sunburn. In extreme cases the X-rays
may cause complete destruction of the skin and
even cancer, and before the properties of the
X-rays were so well known as at present many
operators lost hands, and some their lives, as a
result of excessive exposure to the rays. At present,
X-ray workers shield themselves, and, when
necessary, the patient, with lead screens, that
metal being practically opaque to the rays.

Color Photography

Many workers have tried, with varying
success to devise a means whereby photography
could be made to reproduce not only the outlines
and gradations of natural objects but the
colors as well, and there is now available a
method of great worth for this purpose. In
brief, it consists in making, by one exposure in
an ordinary camera, a set of three-color negatives,
each of which represents that portion of one of the primary
colors—violet, green and red—which was reflected from the subject. That
is, one negative represents the violet “sensation,” the second the green, and
the third the red. Prints are made from these negatives in suitable
dyes on transparent films, which are cemented together, one over the
other, thus giving a true color photograph, in which the secondary and
tertiary colors—blue, yellow, orange, purple, brown, etc.—are obtained,
as in painting, by the mixture in proper proportions of two or more of
the primaries. This is the first method of color photography to possess
the great advantage of producing prints—not transparencies, so that any
number of duplicates may be made. No special camera is required, and
the process is within the reach of any careful amateur. The writer believes
the artistic value of color photography is relatively slight—a black and
white art is capable of the fullest intellectual expression, and color is
merely sensuous in its appeal. After much experiment with different
color processes, he finds his own monochrome (single tone) prints more
satisfying than the color work. However,
the value of color to the scientific
worker is incalculable, as will be realized
at once on considering only one
of the possible applications—namely,
the study of skin affections. It is interesting
to note that several methods
have been devised for the reproduction
of natural colors in motion-picture
work—the familiar method of coloring
the positive film by hand being only an
approximation to truth. But none of
those presented up to this time is fully
satisfactory, though the prospects of
future development are good.

When we consider the manifold
and widespread uses of photography
and the pleasurable diversion that it
affords, it seems safe to say that there
is no other form of industry not an
actual necessity that is of such importance
to the welfare and happiness
of the human race.

By courtesy of Dr. T. W. Harvey

RADIOGRAPH OF NORMAL HAND

SUPPLEMENTARY READING

⁂ Information concerning the above books may be had on application to the Editor of The Mentor.

One summer afternoon, some years ago,
I went into a front room of my home and
drew down the window shades to shut out
the glare and heat. The room became quite
dark, but, in one of the shades, there was
a small hole, through which the sunlight
penetrated—casting on the white wall opposite,
vivid images of all the objects
in the street outside. I had before me
a full-color, moving picture of the panorama
of life that was passing the window.

Here was the original “camera obscura”
(“dark chamber”). If one placed in the
small hole in the shade a glass lens to give a
sharp image, and substituted for the wall
a movable screen, on which the projected
objects could be focussed, one would
have the essential elements of a modern
camera. Through just such simple experiences
as this important scientific discoveries
are sometimes made.

For many years photography was
largely confined to portraiture and the
faithful reproduction of objects and
scenes. All that was expected of a camera
was to “make a picture” of a thing. Within
the last forty years, however, as reproductive
processes have been invented, photography
has come to be one of the most
useful of arts. Beginning about 1883, the
quality and character of the illustrations
in our magazines and books changed
radically. Where, previously, there had
been nothing but hand engravings of one
sort or another, photo-engraving appeared,
and, with that, the horizon of magazine
illustration extended far beyond the
reach of the liveliest imagination. Who
could have foreseen, then, in the first
photo-engraving processes, such possibilities
as photographic printing in full colors,
or moving picture films? Today, pictorial
illustration depends on photography, and
there is apparently little or nothing in life
beyond the reach of photographic art. It
discloses the internal arrangements of
human anatomy; it makes a record of the
affairs of the heavenly bodies; it pictures
things that the human eye cannot see; it
is even potent in the realm of mystery, for
have we not seen photographs of ghosts(?)
reproduced from spirit seances? When
objects and situations in life that do not
exist are wanted, the camera can, by some
trick or device, create them for us.
There seems to be no limit to the possibilities.
Each wonder displayed in
photographic reproduction gives way to
some new effect more wonderful still.

Consider briefly a few of the wonders of
modern photography. First and foremost,
and most spectacular of all, is the moving-picture
film. Then, in the world of practical
things, we have the telephoto-lens—a
combination of the telescope and camera—that
takes pictures of objects far
beyond the reach of the naked eye. This
enables one to photograph the head of a
gargoyle on a distant cathedral, or the
fledglings in an eagle’s nest, or a mountain
goat on a crag high up a mountain side.
Then there is the swinging camera, by
means of which a wide sweep of view can
be included in one plate. A device of
great practical value is photo-telegraphy,
by which portraits for purposes of identification
can be sent by cable and by wireless.
In modern warfare the uses of the
camera are many and varied. They include
panoramic photography, photographing
by moonlight, photographing of
projectiles in the air, even photographing
the noise of a gun by recording the vibrations
due to the displacement of the air,
photo map-making, photo surveying from
the air, and the aviation gun camera.
Radiography, too, must be mentioned—the
X-ray and its use in surgery.

While all these wonders have come to
pass in practical service, photography
has likewise grown and expanded in
the field of fine art. There are photographic
art schools, and clubs and exhibitions—all
for the purpose of cultivating
and developing the camera to the finest
forms of expression. We have highly cultivated
and skilled photographers who are
true artists, and who are engaged in employing
photography as a means to fine
art achievement. Among such artist
photographers in this country mention
should be made of Mr. Paul L. Anderson—the
author of the present article; Arnold
Genthe, who, besides his wonderful portraits,
has, by his art, preserved for future
generations the scenes of old San
Francisco—especially Chinatown—that
have now passed away; Gertrude Käebier,
Baron de Meyer and Jan de Strelecki,
Stieglitz, Eyckmeyer, Steichen, Sümons
and so many others
that the list would fill
this page.

W. D. Moffat
EDITOR

THE MENTOR

The Wealth of The Mentor

• 1 Beautiful Children in Art, by Gustav Kobbé.
• 2 Makers of American Poetry, by Hamilton Mabie
• 3 Washington the Capital, by Dwight Elmendorf.
• 4 Beautiful Women in Art, by Willing.
• 5 Romantic Ireland, by Elmendorf.
• 6 Masters of Music, by Henderson.
• 7 Natural Wonders of America, by Elmendorf.
• 8 Pictures We Love to Live With, by Huneker.
• 9 The Conquest of the Peaks, by Fay.
• 10 Scotland, the Land of Song and Scenery, by Elmendorf.
• 11 Cherubs in Art, by Kobbé.
• 12 Statues with a Story, by Lorado Taft.
• 13 The Discoverers, by Albert Bushnell Hart.
• 14 London, by Elmendorf.
• 15 The Story of Panama, by Bonsal.
• 16 American Birds of Beauty, by E. H. Forbush.
• 17 Dutch Masterpieces, by Van Dyke.
• 18 Paris, the Incomparable, by Elmendorf.
• 19 Flowers of Decoration, by H. S. Adams.
• 20 Makers of American Humor, by Burges Johnson.
• 21 American Sea Painters, by Arthur Hoeber.
• 22 The Explorers, by Albert Bushnell Hart.
• 23 Sporting Vacations, by Dan Beard.
• 24 Switzerland, the Land of Scenic Splendors, by Elmendorf.
• 25 American Novelists, by Hamilton Mabie.
• 26 American Landscape Painters, by Samuel Isham.
• 27 Venice, the Island City, by Elmendorf.
• 28 The Wife in Art, by Kobbé.
• 29 Great American Inventors, by Bruce.
• 30 Furniture and Its Makers, by Richards.
• 31 Spain and Gibraltar, by Elmendorf.
• 32 Historic Spots of America, by McElroy.
• 33 Beautiful Buildings of the World, by Ward.
• 34 Game Birds of America, by E. H. Forbush.
• 35 The Contest for North America, by A. B. Hart.
• 36 Famous American Sculptors, by Lorado Taft.
• 37 The Conquest of the Poles, by Rear Admiral Peary.
• 38 Napoleon, by Ida M. Tarbell.
• 39 The Mediterranean, by Elmendorf.
• 40 Angels in Art, by Van Dyke.
• 41 Famous Composers, by Henry T. Finck.
• 42 Egypt, the Land of Mystery, by Elmendorf.
• 43 The Revolution, by Albert Bushnell Hart.
• 44 Famous English Poets, by Mabie.
• 45 Makers of American Art, by J. T. Willing.
• 46 The Ruins of Rome, by Botsford.
• 47 Makers of Modern Opera, by H. E. Krehbiel.
• 48 Two Early German Painters—Dürer and Holbein, by F. J. Mather, Jr.
• 49 Vienna, the Queen City, by Elmendorf.
• 50 Ancient Athens, by Botsford.
• 51 The Barbizon School, by Hoeber.
• 52 Abraham Lincoln, by A. B. Hart.
• 53 George Washington, by McElroy.
• 54 Mexico, by Frederick Palmer.
• 55 Famous American Women Painters, by Arthur Hoeber.
• 56 The Conquest of the Air, by Woodhouse.
• 57 Court Painters of France, by Coffin, N. A.
• 58 Holland, by Elmendorf.
• 59 Our Feathered Friends, by E. H. Forbush.
• 60 Glacier National Park, by Hornaday.
• 61 Michelangelo, by Cox.
• 62 American Colonial Furniture, by Esther Singleton.
• 63 American Wild Flowers, by Eaton.
• 64 Gothic Architecture, by Ward.
• 65 The Story of the Rhine, by Elmendorf.
• 66 Shakespeare, by Mabie.
• 67 American Mural Painters, by Hoeber.
• 68 Celebrated Animal Characters, by Hornaday.
• 69 Japan, by Elmendorf.
• 70 The Story of the French Revolution, by Albert Bushnell Hart.
• 71 Rugs and Rug Making, by Mumford.
• 72 Alaska, by Browne.
• 73 Charles Dickens, by Mabie.
• 74 Grecian Masterpieces, by Lorado Taft.
• 75 Fathers of the Constitution, by Albert Bushnell Hart.
• 76 Masters of the Piano, by Finck.
• 77 American Historic Homes, by Singleton.
• 78 Beauty Spots of India, by Elmendorf.
• 79 Etchers and Etching, by Weitenkampf.
• 80 Oliver Cromwell, by Albert Bushnell Hart.
• 81 China, by Elmendorf.
• 82 Favorite Trees, by Hornaday.
• 83 Yellowstone National Park, by Elmendorf.
• 84 Famous Women Writers of England, by Mabie.
• 85 Painters of Western Life, by Hoeber.
• 86 China and Pottery of Our Forefathers, by Esther Singleton.
• 87 The Story of The American Railroad, by Albert Bushnell Hart.
• 88 Butterflies, by Holland.
• 89 The Philippine Islands, by Worcester.
• 90 Great Galleries of the World—the Louvre, by Van Dyke.
• 91 William M. Thackeray, by Mabie.
• 92 The Grand Canyon, by Elmendorf.
• 93 Architecture in American Country Homes, by Aymar Embury.
• 94 The Story of the Danube, by Albert Bushnell Hart.
• 95 Animals in Art, by Kobbé.
• 96 The Holy Land, by Elmendorf.
• 97 John Milton, by Mabie.
• 98 Joan of Arc, by Ida M. Tarbell.
• 99 Furniture of the Revolutionary Period, by Esther Singleton.
• 100 The Ring of the Nibelung, by Finck.
• 101 The Golden Age of Greece, by Botsford.
• 102 Chinese Rugs, by Mumford.
• 103 The War of 1812, by Albert Bushnell Hart.
• 104 Great Galleries of the World—The National Gallery, London, by Van Dyke.
• 105 Masters of the Violin, by Finck.
• 106 American Pioneer Prose Writers, by Mabie.
• 107 Old Silver, by Esther Singleton.
• 108 Shakespeare’s Country, by William Winter.
• 109 Historic Gardens of New England, by Mary H. Northend.
• 110 The Weather, by C. F. Talman.
• 111 American Poets of the Soil, by Johnson.
• 112 Argentina, Newman.
• 113 Game Animals of America, by Hornaday.
• 114 Raphael, by Van Dyke.
• 115 Walter Scott, by Mabie.
• 116 The Yosemite Valley, by Elmendorf.
• 117 John Paul Jones, by Albert Bushnell Hart.
• 118 Russian Music, by Finck.
• 119 Chile, by Newman.
• 120 Rembrandt, by Van Dyke.
• 121 Southern California, by C. F. Lummis.
• 122 Keeping Time, by Talman.
• 123 American Miniature Painting, by Mrs. Elizabeth Lounsbery.
• 124 Gems, by Esther Singleton.
• 125 The Orchestra, by Henderson.
• 126 Brazil, by E. M. Newman.
• 127 The American Triumvirate, by A. B. Hart.
• 128 The Madonna and Child in Art, by Van Dyke.
• 129 The Story of the American Navy, by Barnes.
• 130 Lace and Lace Making, by Esther Singleton.
• 131 American Water Color Painters, by Kobbé.
• 132 Peru, by E. M. Newman.
• 133 The Story of the American Army, by Hart.
• 134 Our Planet Neighbors, by Harold Jacoby.
• 135 The Story of Russia, by Leo Pasvolsky.
• 136 The Story of the Hudson, by A. B. Hart.
• 137 Prehistoric Animal Life, by Dr. Matthew.
• 138 Hawaii, by E. M. Newman.
• 139 Earthquakes and Volcanoes, by Talman.
• 140 The Canadian Rockies, by Ruth Kedzie Wood.
• 141 Corot, by Elliott Daingerfield.
• 142 Bolivia, by E. M. Newman.
• 143 Russian Art, by William A. Coffin.
• 144 The American Government, by A. B. Hart.
• 145 Christmas in Picture and Story, by Singleton.
• 146 The Picture on the Wall, by Weitenkampf.
• 147 Lafayette, by Albert Bushnell Hart.
• 148 American Composers, by Henry T. Finck.
• 149 The Luxembourg Gallery, by Wm. A. Coffin.
• 150 Julius Caesar, by Prof. George W. Botsford.
• 151 The Incas, by Osgood Hardy.
• 152 Rodin, by Emile Villemin.
• 153 The Columbia River, by Ruth Kedzie Wood.
• 154 The Story of Coal, by C. F. Talman.
• 155 Benjamin Franklin, by A. B. Hart.
• 156 The Forest, by Henry S. Graves.
• 157 Metropolitan Museum of Art, by S. P. Noe.
• 158 The Cradle of Liberty, by A. B. Hart.
• 159 Rainier National Park, by Belmore Browne.

You need only mail a post card—listing ten or more of the numbers opposite the
titles—and we will send the selections of your choice, all charges paid. Ten copies,
at 20 cents each, may be paid for on easy installments of but $1.00 a month for
two months. We urge you to mail the card to us today.

THE MENTOR ASSOCIATION, 114-116 East 16th Street, New York City

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