AN IMPROVED MEANS OR METHOD OF ILLUMINATING THE SHADOWS AND HARMO-
Year: 1867

page_text: LETTERS PATENT to Franklin Benjamin Gage, of St. Johnsbury, in the
State of Vermont, United States of America, for the Invention of "AN
IMPROVED MEANS OR METHOD OF ILLUMINATING THE SHADOWS AND HARMO-
COMPLETE SPECIFICATION filed by the said Franklin Benjamin Gage
at the Office of the Commissioners of Patents,, with his Petition and
Declaration, on the 29th May 1867, pursuant to the 9th Section of the
Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANKLIN
BENJAMIN GAGE, of St. Johnsbury, in the State of Vermont, United States
of America, send greeting.
WHEREAS, I am in possession of an Invention for "AN IMPROVED MEANS
OR METHOD OF ILLUMINATING THE SHADOWS AND HARMONIZING THE LIGHTS AND
SHADES IN PHOTOGRAPHIC IMPRESSIONS," and have petitioned Her Majesty to
grant unto me, my executors, administrators, aud assigns, Her Royal Letters
Patent for the same, and bave made-solemn declaration that I am the true
and first Inventor thereof.

page_text: NOW KNOW YE, that I, the said Franklin Benjamin Gage, do hereby
declare that the following Complete Specification, under my hand and seal,
fully describes and ascertains the nature of the said Invention, and in what
manner the same is to be performed, in and by the following statement :-
By the usual manner of producing photographic impressions when the
invisible impression is formed in the camera it is removed into a dark room
and at once developed or rendered visible by means of solutions or analogous
ponderable agents. I employ, on the contrary, what may be termed a partial
developement in the camera by the aid of diffused light. The developement is
afterwards completed in the usual way, taking the precaution to reduce the
strength of the developing fluid with water.
I will now proceed to describe what I consider the best manner of pro-
ceeding so that those skilled in the art may be able to understand and use
my Invention with success. I proceed to take a photographic impression in
the manner usually employed; then I place some plain dark dead surface in
front of the camera, the sensitive surface still remaining in the camera; I
then remove the covering from the lens tube and expose the sensitive' surface
on which the impression has been formed to the light reflected from the dark
surface, while the dark surface is kept in gentle motion so as to prevent the
sensitive surface from taking an impression of any wrinkles or other variations
on the surface from which the light is reflected. The time of this exposure
must be varied according to the amount of light reflected and the effect it is
desirable to produce. The usual amount of time occupied in this exposure
will be from one-fourth to double the time employed in taking the invisible
impression; but in some cases it can be extended much beyond this time.
For a dark dead surface I usually use a piece of thick black woollen cloth
about eighteen (18) inches square attached by one edge to a stick about two
(2) feet long, which I hold horizontally and gently move in front of the
camera with the left hand while I uncover the lens tube with the right hand.
It s not absolutely essential that this dark surface be kept in motion, but it
is safer. This exposure of the sensitive surface to the light reflected from a
dark dead surface apparently leaves the lightest portions of the impression
but little changed, while it effects a much greater change in the darkest
: portions of the same, and thus harmonizes and properly blends the two, giving
to the whole an atmospheric effect never before realized in photographic
impressions; it also renders it less difficult to obtain the necessary intensity
in negatives.
It will be understood that my Invention applies equally well and is operated
in the same manner in taking positives or negatives in the camera. I believe

page_text: that it may be used without further instructions in producing any style of
photographic pictures. It is necessary that the dead surface be suitably
lighted, and the time of exposure proportioned to the result desired to be
produced. I believe that the best results are produced when the dead surface
is as strongly lighted as possible without sunlight, using a diaphragm to reduce
the aperture of the lens to prevent the development being so rapid as to
become unmanageable. I have produced excellent results with a silver bath
of twenty grains of nitrate of silver to the ounce of water, being about one
half the usual strength in use, the sensitizing of the collodion being propor-
tionally reduced; I believe it will effect a great saving of expense for this
reason. I believe my Invention also removes the most important obstacle to
the production of dry plate impressions by barmonizing the lights and shades,
which have heretofore usually been hard and inartistic. Exposing the sensitive
surface in the manner described before the impression is formed has less
tendency to blend the lights and shades than when done afterwards; but I
believe it gives a different and peculiar tone to the impression, which in some
cases is very desirable, especially in negatives. When the object to be impressed
is strongly lighted, accompanied with deep heavy shadows, it is found advisable
to illuminate in the manner described the sensitive surface both before and
after the impression is formed; this is effected by moving the black cloth
before the camera a short time before as well as after, and operating otherwise
in the same manner as before described. I believe that some good effect may
be produced by admitting transmitted light upon the sensitive surface, or again
light reflected from yellow and even red and other colored surfaces, either
before or after, or both before and after the photographic impression has been
formed; but I believe that the reflection from a dark dead surface is much to
be preferred, and have described a method of operating which I have found
perfectly convenient and practical for use.
Having now fully described my Invention, what I claim as new and desire
to secure by Letters Patent is as follows:-
First, I claim in photography the employment of diffused light under the
conditions herein specified so as to render visible slight gradations of shade
both in the light and dark parts of the pictures, and to unite softness with
strength, as herein explained and set forth.
Second, I claim in connection with partial developement by diffused light in
the camera reflected from a dark surface the employment of a chemical
developing agent correspondingly weakened, all substantially as and for the
purpose herein set forth.
Third, I claim the employment of a moving black cloth, or equivalent

page_text: dead surface in motion, from which diffused light is thrown upon the
sensitive surface in the camera, substantially as and for the purpose herein
specified.
In witness whereof, I, the said Franklin Benjamin Gage, have hereunto
set my hand and seal, on this Second day of May, in the year of our
Lord One thousand eight hundred and sixty-seven.
FRANKLIN BENJAMIN GAGE. (L.S.)