LEWIS'S PATENT VICES FOR HOLDING THE GLASS--CLEANING AND DRYING
THE GLASS--COATING--EXPOSURE IN THE CAMERA--DEVELOPING--FIXING OR
BRIGHTENING--BACKING UP, &C.
Manipulations.
[Sidenote: MANIPULATIONS.]
Under the head of manipulations I give the method I employ, and avoid
confusion by omitting all comments upon the thousand suggestions of others.
The glass is to have its sharp edges and corners removed, by drawing a
file once or twice over it. The article used for holding the glass is
called a vice. This vice is firmly secured to a bench.
[Since the foregoing pages have been in type there has been introduced
into market a new patent vice, adopted both for glass and plate blocks. I
find it, although a little more expensive, an article better suited to the
wants of the operator or amateur. It is called Lewis's Patent Glass Vice.]
Clasp the glass firmly in the vice, and pour or _spurt_ upon it a little
alcohol and rotten stone, previously formed into a paste, and then, with
a piece of cotton flannel, the same as used in the daguerreotype, rub the
glass until it is perfectly cleansed from all foreign substances, which
will soon be known by experience. The rotten stone paste should not be
allowed to dry while rubbing, as it is more liable to scratch the glass. I
use another small bottle containing clear alcohol, which I spurt upon the
glass, to obviate the drying.
When the glass has been sufficiently cleaned, it should, while wet, be put
in a vessel of water for future rinsing. Clean, as before, as many plates
of glass as may be required, and when enough are ready, rinse them off in
the water, and then in a quantity of clean water, or a running current,
give them a second thorough rinsing, and set them aside to drain.
A convenient method of doing this, is to drive two nails horizontally
into the wall or partition, a sufficient distance apart (say about 2-1/2
inches) for the glass to rest on: the upper corner of the glass should
be placed against the wall, and the extreme lower diagonal corner left
hanging between the nails--which will probably be found the best position
for draining yet suggested.
After drying, they may be put into a box for safe and clean keeping.
Particular caution is necessary to avoid handling the glass during the
operation. I never take the glass between my fingers, so that they come in
contact with _both sides_ of it, except at one particular corner, as at
Figs. A and B. A quantity of glass prepared as above, may be kept on hand
for use two or three days, and when wanted they should be again put into
the vice[C] and cleaned, first with cotton flannel wet with alcohol, and
then with dry flannel; and then, at a temperature slightly above that of
the surrounding atmosphere, except in cases where the thermometer stands
above 70°, it is ready for the brush,[D] which should be carefully applied
to each surface, to free it from all particles of dust, and then it is
ready for the film of collodion.
[Footnote C: The vice should be thoroughly cleansed, and no particles of
rotten stone, or other matter, be allowed to come in contact with the
glass, as it might adhere to the edges and wash off into the silvering
bath, and ultimately cause specks. Always remember that cleanliness is an
indispensable requisite in order to produce a good picture.]
[Footnote D: One of the most desirable articles I have found for this
purpose is the wide (3 inch) flat camel's-hair brush often called a
blender.]
[Illustration: Fig. A. Fig. B.]
The glass is held between the thumb and forefinger of the left hand by the
corner 1, Fig. A., 3 and 4 towards and nearest the body, and as nearly
level as possible. I find this the best position to hold the glass; as, in
the case of the larger ones, they can be rested on the end of the little
finger, which should be placed as near the edge as possible. Then, from
the collodion vial, pour on the collodion, commencing a little beyond
the centre and towards 1, continuing pouring in the same place until the
collodion nearly reaches the thumb--the glass slightly inclined that way;
then let the glass incline towards 4, and continue to pour towards 2.
As soon as enough has been put on to liberally flow the glass, rapidly and
steadily raise corner 1, and hold it directly over 3, where the excess
will flow oil into the mouth of the vial, which should be placed there to
receive it. In case of a speck of dust falling at the time of coating, it
can often be prevented from injuring the surface by changing the direction
of the flowing collodion, so as to stop it in some place where it will
not be seen when the picture is finished. Now, with the thumb and finger
of the right hand, I wipe off any drops or lines of collodion that may be
found upon the _outer_ edge or side of the glass, being careful not to
disturb that connected with the face.
When the coating has become sufficiently dry, so that when I put my finger
against it, it does not break the film, but only leaves a print, I put
it into the silvering bath [_see_ Fig. p. 34]. I generally try corners 2
and 3. The time, from the first commencement of pouring on collodion to
its being put into the bath, should not exceed about half a minute, at a
temperature of 60°. The finger test is the best I have found. The glass
is to be rested on a dipper [_see_ Fig. p. 34], and placed steadily and
firmly into the nitrate of silver bath--this in a dark room. It should not
be allowed to rest for an instant as it is entering the solution, or it
would cause a line. The time for the glass to remain in the bath depends
upon the age and amount of silver the bath contains; for a new solution,
from _two_ to _three_ minutes will be sufficient to give the proper
action. If it be old, three to five minutes will be better. When it is
properly coated, it can be raised up and taken by the corner, and allowed
to drain for a few seconds, and then should be placed in the tablet, and
is ready for the camera. The time of exposure will depend upon the amount
of light present. If the bath is newly mixed, and the collodion recently
iodized, it should produce a sufficiently strong impression by an exposure
of about one-third of the time required for a daguerreotype. If the
collodion has been iodized some time, and the bath is old, about one-half
of the time necessary to produce a daguerreian image will be required.
The plate should in no case be allowed to become dry from the time it
is taken from the bath up to the time of pouring on the developer. At a
temperature of about 70°, I have had the glass out of the bath ten minutes
without drying. After exposure, the glass should be taken again into the
dark room, and removed from the tablet and held over a sink, pail, or
basin and the developing solution poured on it as follows: hold the glass
between the thumb and finger of the left hand, by the opposite end corner
from that in coating with collodion, _i. e._, 2, and let 3 and 4 be from
you.
[Sidenote: MANIPULATIONS OF THE POSITIVE PROCESS.]
Commence pouring on the developing solution at the end by the thumb, and
let it flow quickly and evenly over the entire surface, the first flooding
washing off any excess of nitrate of silver there may be about the edges
or corners of the glass (if this silver is not washed off, it flows over
the edges and on the surface of the impression, producing white wavy
clouds of scum), and then hold the glass as nearly level as possible,
it having upon its surface a thin covering of solution (care should be
observed not to pour the developing solution on the plate in _one place_,
as it would remove all the nitrate of silver and prevent the development
of the image, leaving only a dark or black spot where it is poured on).
Put down the bottle containing the developing solution, and take up a
quart pitcher previously filled with water, and as soon as the outline of
the image can be plainly seen by the weak or subdued light of an oil or
fluid lamp or candle, pour the water over copiously and rapidly. Continue
this until all the iron solution has been removed. If this is not done,
the plate will be covered with blue scum on the application of the washing
solution. Then the glass can be taken into a light room, and the iodide
of silver coating washed off with the cyanide solution, and then rinsed
with clear pure water, and stood in a position to drain and dry. I place
a little blotting paper under them: it aids in absorbing the water, and
facilitates the operation.
Place the face of the glass against the wall, in order to prevent dust
from falling upon it. I have often dried the coating by holding or
standing the glass adjacent to a stove. A steady heat is advisable, as it
leaves the surface in a more perfect state, and free from any scum. After
the coating is perfectly dry, it is ready for the preserving process. It
should be warmed evenly, and when about milk warm, "Humphrey's Collodion
Gilding" is poured on the image in precisely the same manner as the
collodion. In a few seconds the coating sets, and after three-quarters
of a minute, if it has not become dry, the blaze of a spirit lamp
may be applied to the back and it will immediately become _perfectly
transparent_, and nearly as hard as the glass itself: the effect is
fully equal, if not superior, to that of chloride of gold in gilding the
daguerreotype image. The surface becomes brilliant and permanent. The back
of the glass can now be wiped and cleaned with paper or cloth, and gently
warmed, and then with a common small brush one coat of black varnish can
be applied. This brush should be drawn from side to side across the
glass, and on the side opposite to that which has received the image.
This is in order not to make streaks in the coating of varnish, but to
have uniform lines across the entire length or breadth of the glass. If
the varnish is of the proper consistency, it will flow into a smooth,
even coating. After this first coating is dry, apply a second in the same
manner, only in an opposite direction, so as to cross the lines of the
first, uniting at right angles; when this last coating is very nearly dry,
a piece of paper, glazed black on one side, and cut to the proper size,
can be put next the varnish; it gives it a clean finish, at the same time
that it aids towards a dense blackening.
I sometimes apply the black varnish by flowing, in the same manner as in
putting on the collodion.
This picture is to be colored and put up in the same manner as the
daguerreotype image, with a mat and glass. The last glass may be dispensed
with by first using the collodion gilding, and then upon its surface apply
the black varnish, as before. In this case the image is seen through the
same glass it is on, and without being reversed: in this case the mat goes
on the outside of the glass.
When the image is seen through the glass upon which it is taken, it
cannot be colored with very great success, as it cannot be seen through
the reduced silver forming it. This forms a more or less opaque surface;
but in point of economy the single glass is preferable. Yet I would not
recommend such economy, for I consider that a good impression ought to
be well put up, and the welfare of the art fully substantiates that
consideration.
Many ways have been devised for putting up pictures I have produced
pleasing effects upon colored glasses: for instance, a picture on a light
purple glass has a very pleasing effect; also in some other colors. I have
also used patent leather for backing the image.
I have produced curious and interesting results by placing a piece of
white paper, or coloring white the back of the _whites_ of the image,
and then blackening over or around this. By this means the whites are
preserved very clear.
_Positives for Pins, Lockets, etc._--I employ mica for floating the
collodion on, as it can be as easily cut and fitted as the metallic plate
in the daguerreotype; and positives taken upon fine, clear, transparent
mica, are fully equal to those taken upon glass, and yet they are
ambrotypes.
Mica is an article familiar to every one, as being used in stoves,
gratings, etc.
The method of using it, is to take the impression on a thick piece, and
then split it off, which can readily be done in the most perfect, thin,
transparent plates; it is equally as thin as tissue paper, and can be cut
as easily. The thickness of the piece upon which the impression is taken
is of no moment, since it can be reduced at pleasure and is more easily
handled while thick.
Observations on the Positive Collodion Process.
Fogging.--There are numerous causes which will produce fogging: the
principal ones will be mentioned. One is the admission of light upon the
collodion. This maybe from a want of closeness of the dark room, the
tablet,[E] the camera, or by accidental exposure. The method to locate
the particular cause is to, _first_, when the glass is taken from the
nitrate bath, let it stand for sufficient time to drain, then pour on the
developer, and if the coating assumes a mistiness, or light-grey color,
the fault is in the dark room; again, if the plate, after it has been
treated with the developer and fixed, is clear, then also the fault is
there. Now try the tablet in the same manner, and if not there, try the
camera, and the proper location will be found.
[Footnote E: Since the foregoing pages have been in type an entirely new
feature in the line of apparatus has been introduced; this is W. & W.
H. Lewis's Patent Plate-holder with solid glass corners. These Holders
have every requisite for excluding the light from the sensitive surface;
they are accompanied with a "shut off," so that when the slide is drawn
no light can reach the glass. This, in connection with the unequalled
advantage of the solid corners, makes them the most desirable article for
the Operator. _Humphrey's Journal_, in referring to these Holders, says:--
"We are always glad to note every step which our mechanics make
towards improvement on the apparatus used by our practical
photographic operators, and make the present announcement of one
which has only to be known to be readily understood, and to be seen
to be appreciated. A patent has recently been granted for making
solid glass corners, which are to be attached to plate-holders,
and form the most perfect article that has ever been introduced.
Heretofore the operator has had the corners of his plate-holders
made with separate pieces of glass, cut so as to fit the corners of
his frames; these are only glued or grooved in, and are constantly
coming apart, falling out, and annoying in many ways; for our part,
we never have considered them as fit for use in any manner. We look
upon the present improvement as destined to entirely supersede all
the methods heretofore introduced. In this case the collodionized
or albumenized plate can come in contact with no other substance
than a single piece of glass, and consequently there is far less
liability of accident from either the staining of the plate or
breaking of the holder. The rapid favor this improvement has gained
already shows its great advantage over all other methods heretofore
employed."
]
"Decomposition by exposure to light or by long keeping, even in the dark.
The author conceives that it is possible for organic matter alone to
produce, after a time, a partial decomposition of solution of nitrate of
silver, sufficient to prevent it from being employed chemically neutral,
but probably not much interfering with its properties in other respects.
"Use of rain water or of water containing carbonate of silver being
perfectly neutral and from nitric acid. This difficulty is not a
theoretical one only, but has actually been experienced. Rain water
usually contains ammonia, and has a faint alkaline reaction. Pump water
often abounds with carbonate of lime, much of which, but not the whole, is
deposited on boiling. To remove the alkaline condition, add acetic acid,
one drop to half a pint of the solution.
"Partial decomposition of the bath, by contact with metallic iron,
with hyposulphite of soda, or with any developing agent, even in small
quantity. Also by the use of accelerators, which injure the bath by
degrees, and eventually prevent its employment in an accurately neutral
state.
"Vapor of ammonia, or hydrosulphate of ammonia, escaping into the
developing room."
Spots.--One principal cause of spots is _dust_. The operating room
should be kept as free from this as possible, and instead of its being
dusted, it should be wiped with a damp cloth. Specks or flakes of iodide
of silver are often found in the nitrate bath. These sometimes occur by
an ever-iodized collodion, and sometimes by collodion falling off while
being silvered. When this occurs, the nitrate of silver solution should
be filtered. A new sponge or a tuft of cotton is a good article to filter
nitrate of silver solution through. A small particle of light finding its
way upon the plate, will produce a spot. Another and very frequent cause
is, putting the slide of the tablet down rapidly, causing it to spatter
upon the plate the solution which has drained off from it. This paper
will be opaque when viewed by reflected light, and dark when viewed by
transmitted light. Occasionally a sort of transparent spot will appear:
this may be traced to a want of sensibility of the iodide of silver.
Large transparent spots frequently appear by the operator's pouring the
developing solution upon one place, and washing off the small quantity of
nitrate of silver necessary to develope the image. This will be easily
detected, and can be obviated by _flooding_ the most of the surface of the
glass with a steady stream of the developer.
Stains and Lines.--If the glass be allowed to rest for an instant with one
portion of its surface in the silvering solution and the other out of it,
it would cause a streak across; hence the necessity of totally immersing
it with one firm, steady motion removing the glass before it has been
thoroughly wetted, and the ether and alcohol allowed a uniform action over
the entire surface. A plate should not be disturbed in the bath until it
has been in a full minute at least.
_Irregular Lines_ are often caused by using the developing solution too
strong, or by not pouring it evenly over the plate at once. Should it be
allowed to rest in its progress, if but for an instant, it will leave its
line. Sometimes spangles of metallic silver appear: these are caused by
the presence of too much nitric acid in the developer for the proportion
of iodide in the film and the strength of the bath.
There are other phases connected with the practice of the positive
process, which it would be almost impossible to commit to paper, and
cannot be so explained as to be perfectly comprehended by the new
experimenter. It is absolutely necessary for all to observe every little
point noticed in the foregoing pages, and at the same time exercise
some good judgment, and no one need hesitate through fear of not being
successful.
PRACTICAL DETAILS
OF THE
=NEGATIVE PROCESS.=