Towler, John. The Silver Sunbeam.
Joseph H. Ladd, New York: 1864. Electronic edition prepared from
facsimile edition of Morgan and Morgan, Inc., Hastings-on-Hudson,
New York. Second printing, Feb. 1974. ISBN 871000-005-9
IMPERFECTIONS IN COLLODION NEGATIVES AND POSITIVES, AND THEIR
THE knowledge of an imperfection or an error is half the
correction. We must, therefore, first know what the failures in
collodion negatives and positives are. Their enumeration is as
Fogginess; Spots and Apertures; Ridges and Undulating Lines;
Streaks and Stains; Feebleness of the Image, or Deficiency of
Contrast; Harshness or Excess of Contrast; Imperfect Definition;
Solarization; Tender and Rotten Films.
Fogginess.--This is a mist or veil-like appearance that
covers the whole negative; it gives it a foggy or clouded
appearance. This imperfection may be the result of many and various
causes, as for instance: Diffused light in the camera through holes
or chinks; reflections from white or unblackened surfaces in the
camera; diffused light through apertures or chinks in the door
behind the plate in the plate-holder; direct rays of the sun through
the objective or lens; an alkaline, neutral, impoverished or
contaminated state of the nitrate of silver bath; a similar
condition of the collodion certain iodizers in the collodion and at
certain stages of ripening; diffused light in the dark-room; too
intense artificial light in the dark-room; too intense a
development; fumes of ammonia, of turpentine, of tobacco, of
hydrosulphuric acid, and probably almost of any other volatile
chemical substance in the developing-room; imperfect cleanness of a
glass plate that has been used before; the use of gutta-percha baths
Diffused light in the camera, either in front of the plate or
behind it; Reflections from white or unblackened surfaces in the
camera.--This is a certain cause of fogging, and can easily be
remedied. Examine the camera carefully for all chinks and holes.
Some photographers are very care less; they screw on the flanges of
various-sized tubes on the end of the camera,, and neglect filling
the apertures left by the screws when withdrawn. Chinks occur
invariably in cameras made of green wood; and the bellows part, by
frequent adjustment, sometimes cracks. The plate-holder has also its
imperfections; the slide sometimes allows the entrance of light; the
apertures at the bottom, for the passage of accumulating nitrate of
silver, are frequently left open and not filled with sponge, so that
light penetrates in this way. The door behind may close
inaccurately; and the plate-holder may slide irregularly and not
fill the groove calculated to receive it. All these are errors or
defects of workmanship, which must and can be avoided or remedied.
Look, therefore, to your camera first in the search of chinks,
cracks, and apertures; secondly, if the inside surfaces of the
camera are not of a dead black, cover them with unglazed black
woolen or cotton cloth, or wash them over with a thick solution of
ink or lampblack.
Direct rays of the sun through the axis of the lens. Avoid
this evil; like many other troubles, to know it, is its total
An alkaline, neutral, impoverished or contaminated state of
the nitrate of silver bath.--Immerse a piece of reddened litmus
paper in the bath, and see whether it changes color, after a while,
to a blue--if so, the bath is alkaline.
First remedy.--Make a mixture of six drops of acetic acid
in a drachm of water, if you are taking negatives, and of the same
quantity of nitric acid and water, if you are taking positives; add
ten drops at a time of either solution until the fogging disappears.
Sometimes even more acid may be required.
Second remedy.--Instead of adding acid to the bath, add an
old collodion or tincture of iodine to your collodion in present
use; this frequently is the safest plan of action.
If the bath is impoverished, it will at the same time be
contaminated. The remedy is to boil it some time in a glass
flask in order to get rid of the ether, alcohol, and the volatile
substances produced by decomposition, as also to coagulate organic
matter; then allow the bath to cool, and filter. To the filtrate add
more nitrate of silver if required. Placing an old bath in
the sun for several days is also of great assistance, but it is far
from being equal to boiling or distilling.
Certain iodizers in the collodion and at certain stages of
ripening.--Iodide of cadmium alone frequently produces fogginess;
almost any new and limpid collodion has the same effect. Add iodide
of ammonium in the first case, and an old collodion or tincture of
iodine in the second case; the sensitiveness will be thereby
probably diminished, whilst the condition to fog will be
Diffused light in the dark--room, or too intense an artificial
light.--Place the artificial light behind a piece of ground glass,
and do not bring it near the negative until the latter is thoroughly
fixed. Diffused light must be locked out of the room.
Too intense a developer.--In summer less of the developer,
whether of iron or pyrogallic acid, or more of the acid is required
than in winter, otherwise fogging will be the consequence--the
property of acid is to restrain the action of the developer; use
your judgment, therefore, and do not always keep to the same amount
of protosulphate of iron, or pyrogallic acid to the ounce of water
in all seasons; nor restrict yourself unconditionally to the same
amount of acid in the developer.
Fumes of ammonia, etc.--Keep your dark-room solely for its
legitimate purposes. Keep it rigidly clean; perform no chemical
experiments in it; abjure smoking in this sanctum; do not sensitize
your papers or fuminate with ammonia in this room; make no manner of
Imperfect cleanness of the plate, etc.--Wash the old plates with
a solution of salts of tartar and water; if this does not remove the
adhering dirt, wash it with dilute nitric acid, and afterward with
salts of tartar, and finally clean and polish the plate with
rotten-stone and alcohol. Some old plates that have lain long in
water in which the old developing solutions have been thrown I have
never succeeded in cleaning so as to prevent fogging; they are
contaminated to the backbone.
The use of gutta-percha baths, etc.--Instead of these, use glass,
porcelain or photographic ware baths--the latter are very highly
recommended; I prefer glass to every other material.
Spots and Apertures.
Opaque and transparent specks are the most troublesome annoyances
in the collodion negative process, and occur to every photographer
more or less. These can be attributed to various causes, but seldom
for the time being to the right cause; that is, we know in general
what will cause them, but seldom what did cause them.
The opaque spots may be caused in the first place by
dust on the surface of the glass before the collodion is
poured on. The remedy is simple: brush off the dust with a broad,
flat camel's hair pencil just before the collodion is applied.
Secondly.--Opaque spots may be caused by dust on
the surface of the collodion; this dust may be deposited either from
the bath itself, previous to immersion in the bath, or in the camera
during exposure. That which is deposited either before or after
immersion, are the organic substances in a state of very minute
division floating about in the atmosphere or set in motion within
the camera by the agitation produced with the plate-holder. This is
perhaps the most fruitful source of trouble, which is of two kinds,
opaque and transparent spots. The particles of dust
attach themselves to the collodion with different degrees of
tenacity; where the tenacity is small, the dust is washed off; in
the different manipulations of developing and fixing, and the
consequence is the production of transparent specks; on the
contrary, where the tenacity is great, opaque spots are the
result; for the particles remain imbedded after the final washing.
If the dust be deposited from the bath itself, it may arise either
from organic materials, in the atmosphere or from an excess of
iodide of silver in the bath, in the form of the violet-colored
deposit found at the bottom or on the walls of the bath. The remedy
is, in the first case, to keep your room-floors moist, and your
camera perfectly free from this enemy by dusting and sponging. In
the second place, the insoluble deposit in the bath is separated by
filtration; the bath, too, is thoroughly cleaned by a sponge tied to
the end of a rod, which can be made to enter into the angular spaces
in which the dust is deposited.
Thirdly.--Another source of this trouble with opaque spots
is to be found in the collodion, which contains sometimes
undissolved pyroxyline in the form both of dust and fibres, or in
fine organic dust from impure sources of manipulation. To remedy the
evil, allow the collodion to settle thoroughly and use only the
clear supernatant part.
These are of much more frequent occurrence than opaque spots.
They may arise, in the first place, from undissolved particles of
the iodides in the ether and alcohol of the collodion; this is
particularly the case with iodide of potassium in anhydrous alcohol;
these afterward become dissolved in the subsequent operations. The
remedy is a drop or two of water, or of diluted alcohol, or of
bromide of ammonium.
As remarked in reference to opaque spots, particles of dust in
the camera or of the insoluble iodide of silver in the bath,
adhering to the surface of the collodion, produce specks, both
opaque and transparent. The transparent ones result from the fact
that, during exposure, and the dust particles being opaque, they
prevent the rays of light from acting actinically on the collodion
film beneath, and then, being washed off in the subsequent
manipulations of development, fixing, intensifying, and washing,
they leave the collodion in those parts to the mercy of the fixing
solutions, which render them quite transparent. The remedy is to
keep the camera and the room free from dust, and the bath from
insoluble particles of the iodide of silver or organic materials. If
the bath is the cause, the trouble may be avoided by keeping the
plate in motion during sensitization.
Another cause of transparent spots, and probably a very frequent
one, is to be attributed to a crystalline deposit of iodo-nitrate of
silver, which, as the bath becomes weaker, is precipitated in a
crystalline form on the surface of the collodion film. This form of
deposit occurs with an old bath. Its remedy is to precipitate it out
of the bath by adding water, and then by filtration. Then for every
ounce of water thus added pour in after filtration the same amount
of a nitrate of silver solution to take its place.
When the bath is the cause of transparent spots, a small quantity
of a solution of chloride of sodium (common salt) thrown in is found
to be of great benefit. Chloride of silver and nitrate of soda are
formed by double decomposition; the insoluble chloride probably
carries down with it the dust or particles which are the cause of
the trouble, or the nitrate of soda dissolves them. I am not able to
say what is the true explanation. After filtration the bath is
raised to the proper strength, when it will be found to be free from
Ridges and Undulating Lines.
These are caused by the too great consistency of the collodion,
and are found in the direction of the current of the collodion. The
remedy is to add sufficient ether to cause the collodion to flow
smoothly, easily, and uniformly over the plate. The mottled
appearance sometimes apparent on a collodion film, as if covered
with flocks of wool, is owing also to the thickness of the
collodion, and the evil is remedied in the same manner as the
Streaks and Stains.
Streaks may arise from an irregularity in the immersion of
the plate in the silver bath, or in withdrawing it; the plate has to
be immersed or withdrawn without any stopping. Streaks and stains
are produced, too, by the film of dust swimming on the surface of
the vertical bath, which is carried down on the collodion when the
plate is immersed.
They arise, secondly, from the irregular flowing of the
developing solution; the remedy is to use the gutta-percha
developing dish already recommended for such purposes. Another
remedy may be a proper quantity of alcohol added to the developer,
if there happen to be a sort of greasiness or repulsion in the
collodion film to the developing solution as it flows along.
The part upon which the developer first comes in contact with the
collodion film almost invariably exhibits a streak around a denuded
part, as if the developer had swept off the latent image in that
part. The remedy is the developing dish, by which the developer acts
with little or no momentum greater at one part than at another.
A sort of fortification system of stains and streaks arises from
the want of cleanness of the corners of the plate-shield, from an
inferior quality of collodion, from the unequal dryness of the film
before immersion in the silver bath, as well as from a too great and
irregular dryness of the film after exposure and before development.
The remedies are self-apparent; avoid the causes.
Stains of a blue color arise from imperfect washing between
developing and fixing.
Feebleness of the Image, or de
deficiency of Contrast.
A new collodion will very frequently be one cause of this
trouble--the materials are not yet ripe. As a remedy, add old
collodion, or wait for a few days, until the collodion is
Over-exposure is another and very frequent cause of a
feeble contrast in the picture. All the parts are developed
simultaneously, and too much deposit of reduced silver is the result
all over the picture. A shorter exposure is the remedy.
Too intense a developer, or a developer continued too
long, fogs the picture and weakens the contrast.
Imperfect lighting, is a third cause, in which the light
is either small in quantity, or diminished in intensity bar reason
of peculiarities in the atmosphere.
Harshness, or Excess of Contrast.
Under-exposure, a too acid bath, a too acid developer,
underdevelopment, an old and insensitive collodion: all these
will produce pictures of mere black and white; the intermediate
tones are totally wanting. The remedy is apparent; use it as the
case may be.
This may be caused by the want of coincidence in the
chemical and luminous focus. See that the surface of the ground
glass and that of the inserted plate have exactly the same distance
from the back lens, and correct this evil according to rules already
The want of sharpness may arise from careless focussing,
from the mobility of the sitter during exposure, from a
change of position in the camera when inserting the
sensitized plate, or, in fine, from a bad lens. The remedy in
everyone of these cases is obvious, excepting perhaps in the last;
for the photographer may not always be in a condition to get a
better lens. The only and most advisable remedy in this case is to
close his gallery and feign sickness, until the return of the
Express from the city, rather than lose his reputation or gain a bad
one. In many cases a microscope is employed in very refined
focussing, especially in copying.
This trouble does not occur very frequently; it is made manifest
by the redness which the high-lights are wont to assume during
development, when the exposure has been either too long or the light
too brilliant, as in the copying process by the direct rays of the
sun. This evil can be remedied by avoiding the causes, or by the use
of a bromo-iodized collodion, or of citric acid in the
Tender and Rotten Films
These occur generally in collodion of a certain make, owing to
the peculiar nature of the pyroxyline, or the relative quantity of
alcohol and ether. The defect may arise, however, by immersing the
plate too quickly into the silver bath before the film has set; also
by immersing the plate when the film is too dry, in which case it
cracks and splits up in the development.
There is no remedy for a rotten film; but a tender or
structureless film can be retained on the glass by first filing the
edges as recommended, and then by careful manipulations in the
various operations of developing, fixing, and washing.
Imperfections in Paper Prints.
These are to be attributed to defects in the paper; to
Imperfect albumenizing and salting; to defective sensitizing; to
defects in the printing or in the negative; to imperfect washing
previous to toning; to defective toning; to defective fixing; to
stains of various kinds; meatiness on the print.
Defects in the Paper.
A defective piece of paper must always be rejected at once. By
regarding the paper by transmitted light, very frequently
imperfections in the substance of the material can be descried,
which otherwise would escape observation. Particles of inorganic
matter, such as lime, the oxide of iron, etc., may be found in the
substance, which in the various stages of the printing operation
become manifest by decomposition. In choosing paper, where you can
make the selection, examine each sheet separately for mechanical
defects both of structure and of contamination, and reject whatever
is in any way defective.
Imperfect Albumenizing and
The albumenizing and salting require careful and neat management.
If the albumen is not very thoroughly broken up, it will assuredly
produce irregularities in the albumenizing. The salting materials
must be mixed up at the same time with the albumen, but after
solution in a small quantity of water; otherwise particles of
the salt will remain undissolved and give a spotted
appearance in the printing. Use the albumen while fresh. See that
the surface is not composed of bubbles; where these exist you will
have a marbled or oölitic appearance on your
print. If the paper exhibits such minute bubbles when removed from
the salting solution, break these bubbles all up with a clean
feather or soft sponge, and goat the paper again until the film is
uniform. The amount of salting ought to bear a relation of
equivalents with the silver solution used subsequently.
Filter the silver solution before use, or at least remove all
particles of dust or oxide from its surface, otherwise your prints
will be spotted and frequently covered with
fortifications. A marbled appearance is caused by a
weak silver solution, or too short a time of floating. It may arise
from defects in the albumenizing, as just referred to. In quick
floating the solution must be very strong. In some cases the
solution seems to be rejected from the surface of the albumen; rub
over the solution with a tuft of cotton; float again, and the
trouble will be overcome.
Defects in the Printing or in the
A weak negative will inevitably produce a weak
print. Weak prints, too, are the result of too dilute a silver
solution. Bronzing arises frequently from a want of true
relation between the lights and shades in the negative. An
intensified ambrotype used as a negative will produce a bronzed
picture. Thus under-exposure and over-development are
the causes of bronzing.
A harsh print proceeds also from under-exposure and
over- development in the negative; there is a want of
middle-tone--the picture is all black and white.
Many prints are spoiled in the act of printing by extreme
carelessness. Watch the operation; the two guides of success are:
Print as long as the high-lights are perfectly white, and
bronzing has not yet commenced. The impression of a perspiring
finger on the sensitive film, as well as many other similar organic
contaminations, also give rise to bronzing.
Imperfect Washing previous to
The print, when removed from the printing-frame, contains nitrate
of silver and nitrate of the alkalies used in the salting solutions,
albuminate of silver, chloride of silver; the latter salt has been
partly acted upon by fight so as to form the picture, and another
part has not been changed. The nitrates must all be removed by
careful washing in several waters before the toning is commenced,
otherwise the toning will be slow and imperfect.
The operation of washing must take place soon after printing
and immediately before towing, in order to secure a good and
This imperfection may arise from contaminations introduced into
the toning solution by imperfectly washed prints; the gold solution
becomes thereby decomposed and incapable of toning the printed film.
The defect may arise from impure chloride of gold; from an acid
condition of the toning solution; from bad paper; from the lowness
of the temperature; from an excess of elevation of temperature. The
imperfections of toning are
A red tone after fixing; this is owing to an insufficiency
A blue tone after fixing; this is owing to an excess of
toning; or to an acid toning solution.
A yellow tone in the whites after fixing; this may be
owing to imperfect washing, imperfect toning, imperfect fixing,
dirty fingers, introduction of hyposulphite of soda into the toning
solution, or upon the prints. The defect in question may arise also
from the decomposition of the gold in patches, for want of uniform
mixture before the prints are introduced.
A dark mottled appearance in the body of the paper
indicates imperfect fixing combined with the action of the light on
the unaltered chloride during fixing. An exhausted
hyposulphite bath may also give rise to this defect. A bath
containing hydrosulphuric acid, or a free acid, which will produce
the former, gives rise to this dark-gray mottled defect.
A yellow tone in the whites arises very frequently from
sulphurized hyposulphite stains of various kinds.
These are owing to irregular and careless manipulations. The
introduction of the fingers into the various baths, and
indiscriminately from one bath into another, is the cause of a
number of stains on the prints, as well as of abnormal action of the
Make rules for yourself, such as the following, and observe them
- Print just to bronzing, or until the whites begin to be
- Wash soon after printing in clean water and clean pails.
- Move the prints about in the washing; repeat the washing three
times; two or three minutes' duration for each is enough. Long
washing is injurious.
- The chloride of gold must be pure; the solution must be
neutralized with alkalies or lime.
- The toning solution must be warm--about 100°--and well
- Wash after toning quickly--in warm or hot water preferable--take
care to introduce no gold solution into the fixing solution, and
- Move the prints about in all the solutions, so as to avoid
bubbles and uneven action.
- Tone to purple or incipient violet.
- Use fresh toiling for a fresh batch of prints.
- Add fresh hyposulphite every time to the old bath, or use a
fresh fixing-bath every time; let the bath be warm.
- Alcohol is an advantage in all the solutions beginning with the
nitrate of silver to the hyposulphite of soda.
- Wash very thoroughly after fixing.
Mealiness on the Print.
Some authors speak of this defect in albumen prints. It is said
to proceed from paper that has been long albumenized, or from the
paper itself. The remedy is to immerse the prints in a solution of
two ounces of water and eighteen grains of acetate of soda, and to
keep them in this liquid for about ten minutes.
Prints frequently appear as if covered with snow, but the
surface is quite smooth and the whites clear; this defect is
attributable to the negative, which has been strengthened by
pyrogallic acid containing too much nitrate of silver. The surface
of the negative becomes thereby covered with a pulverulent deposit.
There is no remedy for such a negative; there is a remedy, however,
to such a mode of intensifying. In the first place, the negative
must contain the middle tones before you begin to intensify;
secondly, intensify slowly, which is effected by adding only three
or four drops of silver at a time to the pyrogallic acid, and
shaking well before use.