camera with a movable holder. This camera and the original negative to
be reduced are fastened to the opposite ends of a long, heavy board,
similar to the arrangement in use for the making of lantern slides.
The camera must be movable in the direction of the objective axis, and
the negative must be fastened to a vertically stationary stand. It is
then uniformly lighted from the reversed side by either daylight or
artificial light. Some difficulty is experienced in getting a sharp
focus of the picture. The ordinary ground glass cannot be used, not
{551} being fine enough, and the best medium for this purpose is a
perfectly plain piece of glass, coated with pretty strongly iodized
collodion, and sensitized in the silver bath, the same way as in the
wet process. The focusing is done with a small lens or even with a
microscope. The plate intended for the picture has, of course, to
lie in exactly the same plane as the plate used for focusing. To be
certain on this point, it is best to focus upon the picture plate,
inserting for this purpose a yellow glass between objective and plate.
If satisfactory sharpness has been obtained, the apparatus is once for
all in order for these distances. Bromide of silver gelatin plates, on
account of their comparatively coarse grain, are not suitable for these
small pictures, and the collodion process has to come to the rescue.
Dagron, in Paris, a prominent specialist in this branch, gives the
following directions: A glass plate is well rubbed on both sides
with a mixture of 1,000 parts of water, 50 parts powdered chalk, and
200 parts of alcohol, applied with a cotton tuft, after which it is
gone over with a dry cotton tuft, and thereafter cleaned with a fine
chamois leather. The side used for taking the picture is then finally
cleaned with old collodion. The collodion must be a little thinner than
ordinarily used for wet plates. Dissolve
Ether 400 parts
Alcohol 100 parts
Collodion cotton 3 parts
Iodide ammonia 4 parts
Bromide ammonia 1 part
The plate coated herewith is silvered in a silver bath of 7 or 8 per
cent. From 12 to 15 seconds are sufficient for this.
The plate is then washed in a tray or under a faucet with distilled
water, to liberate it from the free nitrate of silver and is afterwards
placed upon blotting paper to drip off. The still moist plate is then
coated with the albumen mixture:
Albumen 150 cubic centimeters
Add
Water 15 cubic centimeters
Iodide potassium 3 grams
Ammonia 5 grams
White sugar 2 grams
Iodine, a small cake.
With a wooden quirl this is beaten to snow (foam) for about 10 minutes,
after which it must stand for 14 hours to settle. The albumen is
poured on to the plate the same as collodion, and the surplus filtered
back. After drying, the plate is laid for 15 seconds in a silver bath,
consisting of 100 parts of water, 10 parts nitrate of silver, and 10
cubic centimeters of acetic acid. The plate is then carefully washed
and left to dry. If carefully kept, it will retain its properties for
years. To the second silver bath, when it assumes a dirty coloration,
is added 25 parts kaolin to each 100 parts, by shaking the same well,
and the bath is then filtered, after which a little nitrate of silver
and acetic acid is added.
After each exposure the plate holder is moved a certain length, so that
10 or more reproductions are obtained upon one and the same plate. The
time of exposure depends upon the density of the negative and differs
according to light. It varies between a second and a minute.
The developer is composed as follows:
Water 100 parts
Gallic acid 0.3 parts
Pyro 0.1 part
Alcohol 2.5 parts
The exposed plate is immersed in this bath, and after 10 to 20
seconds, from 1 to 2 drops of a 2 per cent nitrate of silver solution
are added to each 100 cubic centimeters of the solution, whereby the
picture becomes visible. To follow the process exactly, the plate has
to be laid—in yellow light—under a weakly enlarging microscope, and
only a few drops of the developer are put upon the same. As soon as
the picture has reached the desired strength, it is rinsed and fixed
in a fixing soda solution, 1 to 5. Ten to 15 seconds are sufficient
generally. Finally it is washed well.
After the drying of the plate, the several small pictures are cut
with a diamond and fastened to the small enlarging lenses. For this
purpose, the latter are laid upon a metal plate heated from underneath,
a drop of Canada balsam is put to one end of the same, and, after it
has become soft, the small diapositive is taken up with a pair of
fine pincers, and is gradually put in contact with the fastener. Both
glasses are then allowed to lie until the fastener has become hard. If
bubbles appear, the whole method of fastening the picture has to be
repeated.
«Photographs on Brooches.»—These may be produced by means of a paper
(celuidin paper) whose upper layer after exposure by means of ordinary
negative can be detached in lukewarm water. The picture copied on this
paper is first laid in tepid water. After a few minutes it is taken
out and placed on the article in question, naturally with the face
upon it. The enamel surface upon which the {552} picture is laid is
previously coated with gelatin solution to insure a safe adhesion. When
dry, the article is placed in water in which the paper is loosened and
the photographic image now adheres firmly to the object. It may now be
colored further and finally is coated with a good varnish.
«FLASHLIGHT POWDERS AND APPARATUS.»
Flash powders to be ignited by simply applying the flame of a match
or laying on an oiled paper and igniting that, may be made by the
following formulas:
I.—Magnesium 6 parts
Potassium chlorate 12 parts
II.—Aluminum 4 parts
Potassium chlorate 10 parts
Sugar 1 part
The ingredients in each case are to be powdered separately, and then
lightly mixed with a wooden spatula, as the compound may be ignited by
friction and burn with explosive violence.
It is best to make only such quantity as may be needed for use at the
time, which is 10 or 15 grains.
«To Prevent Smoke from Flashlight.»—Support over the point where the
ignition is to take place a large flat pad of damp wool lint. This may
be done by tacking the lint to the underside of a board supported on
legs. When ignition takes place the products of combustion for the most
part will become absorbed by the wool.
«A Flashlight Apparatus with Smoke Trap.»—A light box, not too large
to be conveniently carried out into the open air, is the first
essential, and to the open front of this grooves must be fitted, in
which grooves a lid will slide very easily, a large sheet of millboard
being convenient as a sliding lid. The box being so placed that the
sliding lid can be drawn out upward, a thread is attached to the lower
edge of the lid, after which the thread is passed over a pulley fixed
inside the box near the top, when the end is attached to the bottom
of the box, so that the thread holds the sliding lid up. The lid will
then slide down the grooves quickly, and close the box, if the thread
is severed, the thread being cut at the right instant by placing the
lower part across the spot where the flash is to be produced. So small
is the cloud of smoke at the first instant that practically the whole
of it can be caught in a drop trap of the above-mentioned kind. If
the apparatus is not required again for immediate use, the smoke may
be allowed to settle down in the box; but in other cases the box may
be taken out into the open air, and the smoke buffeted out with a
cloth. In the event of several exposures being required in immediate
succession, the required number of apparatus might be set up, as each
need not cost much to construct.
«INTENSIFIERS AND REDUCERS:»
«Intensifier (Mercuric) with Sodium Sulphite, for Gelatin Dry
Plates.»—Whiten the negative in the saturated solution of mercuric
chloride, wash and blacken with a solution of sulphite of sodium, 1 in
5. Wash well.
The reduction is perfect, with a positive black tone.
«Intensifier with Iodide of Mercury.»—Dissolve 1 drachm of bichloride
of mercury in 7 ounces of water and 3 drachms of iodide of potassium in
3 ounces of water, and pour the iodide solution into the mercury till
the red precipitate formed is completely dissolved.
For use, dilute with water, flow over the negative till the proper
density is reached, and wash, when the deposit will turn yellow. Remove
the yellow color by flowing a 5 per cent solution of hypo over the
plate, and give it the final washing.
«Agfa Intensifier.»—One part of agfa solution in 9 parts water (10 per
cent solution). Immerse negative from 4 to 6 minutes.
«Intensifying Negatives Without Mercury.»—Dissolve 1 part of iodine
and 2 parts of potassium iodide in 10 parts of water. When required
for use, dilute 1 part of this solution with 100 parts of water. Wash
the negative well and place in this bath, allowing it to remain until
it has become entirely yellow, and the image appears purely dark
yellow on a light-yellow ground. The negative should then be washed in
water until the latter runs off clearly, when it is floated with the
following solution until the whole of the image has become uniformly
brown:
Schlippe’s salt 60 grains
Water 1 ounce
Caustic soda solution, 10 per cent 6 drops
Finally the negative is again thoroughly washed and dried. The
addition of the small quantity of caustic soda is to prevent surface
crystallization. It is claimed that with this intensifier the operation
may be carried out to a greater {553} extent than with bichloride
of mercury; that it gives clear shadows, and that it possesses the
special advantage of removing entirely any yellow stain the negative
may have acquired during development and fixing. Furthermore, with this
intensifying method it is not necessary to wash the negative, even
after fixing, as carefully as in the case of the intensifying processes
with mercury, because small traces of hypo which may have been left
in the film will be rendered innocuous by the free iodine. The iodine
solution may be employed repeatedly if its strength is kept up by the
addition of concentrated stock solution.
«Uranium Intensifier.»—
Potassium ferricyanide (washed) 48 grains
Uranium nitrate 48 grains
Sodium acetate 48 grains
Glacial acetic acid 1 ounce
Distilled water to 10 ounces.
Label: Poison. Immerse the well-washed negative till the desired
intensification is reached, rinse for 5 minutes and dry. This
intensifier acts very strongly and should not therefore be allowed to
act too long.
«MISCELLANEOUS FORMULAS:»
«Renovating a Camera.»—The following formula should be applied to the
mahogany of the camera by means of a soft rag, rubbing it well in,
finally polishing lightly with a clean soft cloth:
Raw linseed oil 6 ounces
White wine vinegar 3 ounces
Methylated spirit 3 ounces
Butter of antimony 1/2 ounce
Mix the oil with vinegar by degrees, shaking well to prevent separation
after each addition, then add the spirit and antimony, and mix
thoroughly. Shake before using.
«Exclusion of Air from Solutions.»—Water is free from air only when
it has been maintained for several minutes in bubbling ebullition. In
order to keep out the air from the bottle, when using the contents, the
air-pressure contrivances are very convenient; one glass tube reaching
through the rubber stopper into the bottle to the bottom, while the
second tube, provided with a rubber pressing-ball, only runs into
the flask above. If the long bent tube is fitted with a rubber tube,
a single pressure suffices to draw off the desired quantity of the
developer. It is still more convenient to pour a thin layer of good
sweet oil on top of the developer besides. The developer is not injured
thereby, and the exclusion of air is perfect.
«Bottle Wax.»—Many ready-prepared solutions, such as developers and
other preparations from which light has to be excluded, should be
packed in bottles whose neck, after complete drying of the stopper,
is dipped in a pot with molten sealing wax. A good recipe is the
following, pigments being added if desired: For black take: Colophony,
6 parts; paraffine, 3 parts. Melt together and add 20 parts of black.
For yellow, only 7 parts of chrome yellow. For blue, 7 parts of
ultramarine.
«Bleaching Photographic Prints White.»—To make a salt print, ink over
it with waterproof ink, then bleach out white all but the black lines.
Sensitize Clemon’s mat surface paper on a 40-grain bath of nitrate of
silver. After fuming and printing, the print is thoroughly fixed in
hyposulphite of soda solution, and washed in running water until every
trace of the hypo is out of the print. On this the permanency of the
bleaching operation depends. The bleaching bath is:
Bichloride of mercury 1 ounce
Water 5 ounces
Alcohol 1 ounce
Hydrochloric acid 1 drachm
If the drawing has been made with non-waterproof ink, then alcohol is
substituted for the water in the formula. For safety, use an alcoholic
solution of mercury. The bleaching solution is poured on and off the
drawing, and, when the print is bleached white, the mercury is washed
off the drawing by holding it for a few moments under running water.
Photographs bleached in this way will keep white for years.
«To Render Negatives Permanent.»—A fine negative, one that we would
like to preserve, may be rendered permanent by placing it, after it has
been fixed, in a 10 per cent solution of alum, and letting it remain
a few minutes. This makes the plate wonderfully clear and clean, and
absolutely unalterable. The alum acts upon the gelatin, rendering it
insoluble.
«Stripping Photograph Films.»—This is generally done by immersing
the plate in formaldehyde solution until the film has become almost
insoluble and impermeable. Then it is placed in a solution of sodium
carbonate until the gelatin has absorbed a sufficient quantity of
it. When the negative is immersed in weak hydrochloric acid, carbon
{554} dioxide is liberated, and the little bubbles of gas which lodge
themselves between the film and the glass cause a separation of the
two, so that the film may be stripped off. After having hardened the
film with formaldehyde, it is a lengthy process to get it saturated
with sodium carbonate. It is advisable to use a combined bath of 1
part of carbonate, 3 of 40 per cent formaldehyde, and 20 of water; its
tanning action is enhanced by the alkaline reaction, and two operations
are superseded by one. After 10 minutes’ soaking, the surface of the
film must be wiped and the plate dried. A sharp knife is then used to
cut all around the film a slight distance from the edge, and when this
is done the negative is put into a 5 per cent solution of hydrochloric
acid, when the film will probably float off unaided; but, if necessary,
may be assisted by gently raising one corner.
«Phosphorescent Photographs.»—The necessary chemicals belong to the
class of phosphorescent bodies, among others, calcium sulphite,
strontium sulphite, barium sulphide, calcareous spar, fluorspar. These
placed in the magnesium light or sunlight, acquire the property of
giving forth, for a shorter or longer time, a light of their own. The
best examples of these substances are the well-known “Balmains light
colors,” which yield a very clear and strong light after exposure. They
consist of calcium sulphide, 10,000 parts; bismuth oxide, 13 parts;
sodium hyposulphite, 1,000 parts.
According to Professor Schnauss, plates for phosphorographs are
prepared as follows: Dissolve 10 parts of pure gelatin in 50 parts of
hot water, add and dissolve 30 parts of “light” color (as above), and
1 part of glycerine.
If a plate or a paper, prepared as above detailed, be placed under
a diapositive, in a copying apparatus, and submitted to the action
of sunlight for a few minutes, when taken out in a dark room a
phosphorescent picture of the diapositive will be found. It is also a
known fact that duplicate negatives or positives may be made with this
phosphorograph by simply bringing the latter in contact in a copying
apparatus, with the ordinary silver bromide plate for 30 seconds, in
the dark room, and then developing the same.
«Printing Names on Photographs.»—The name or other matter to be printed
on the photograph is set up in type, and printed on cardboard; from
this make an exposure on a transparency plate, developing it strongly.
After the print has been made from the regular printing negative, it
is placed under the dense transparency of the regular negative, and
the name printed in. The only precaution necessary is to time the
transparency negative properly, and develop strongly, so as to get good
contrast. Photographers will find this a much easier and quicker method
than the old one of printing on tissue paper and fastening the paper to
the negative by means of varnish; moreover, the result is black instead
of white, usually much more pleasing.
«Spots on Photographic Plates.»—Spots on photographic plates may be
caused by dust or by minute bubbles in the emulsion, both of which
are easily preventable, but some spots cannot be ascribed to either
of these causes. On investigating this trouble, Mumford found that it
is due to the presence on the surface of the film of small colonies
of microorganisms which, under conditions favorable to their growth,
are capable of producing large mold colonies, from which the organisms
can easily be separated. Experiments were instituted in order to find
whether these growths can be produced on the plate by artificial
means, by inoculating the surface with a fluid culture of one of these
organisms, with affirmative results, but with one slight difference,
namely, that in the inoculated film, on microscopic examination,
no dust particle was visible in the center of each spot, which had
formerly been the case. As these microorganisms do not exist in the
air as isolated units, but travel upon small or large dust particles
in the case under consideration, the carrying medium most probably is
the fine impalpable dust from which it is practically impossible to
free the air of a building. In order that these organisms may grow
into colonies of sufficient size to cause spots, they must be able to
grow rapidly, there being only about 12 hours before the plate is dry
in which they can grow; and they must also be capable of growing at
the rather high temperature of 70° F. On testing some of the organisms
causing the spots it was found that they grew best under exactly such
conditions. A bacteriological examination of some of the gelatin used
in the manufacture of plates, both in the raw state and in the form of
emulsion, also revealed the fact that there were numerous organisms
present. No means for the prevention of this troublesome defect is
suggested; {555} most dry-plate manufacturers use the precaution to add
a small quantity of a chemical antiseptic to the emulsion, but it is
not possible to employ a sufficient quantity to destroy any organisms
that may be present without damaging the plate for photographic
purposes.
«To Remove Pyro Stains from the Fingers.»—Make a strong solution of
chlorinated lime; dip the fingers which are stained in this, and rub
the stains with a large crystal of citric acid. Apply the lime solution
and acid alternately until the stain is removed; then rinse with water.
«To Remove Pyro Stain from Negatives.»—Immerse in a clearing bath as
follows:
Protosulphate of iron 3 ounces
Alum 1 ounce
Citric acid 1 ounce
Water 20 ounces
Prevention is better than cure, however; therefore immerse the
negatives in the above directly they are taken from the fixing bath.
After clearing the negatives, they should be well washed.
PHOTOGRAPHY WITHOUT LIGHT: See Catatypy.
PIANO POLISHES: See Polishes.
PICKLE FOR BRASS: See Brass and Plating.
PICKLE FOR BRONZE: See Bronze Coloring.
PICKLE FOR COPPER: See Copper and Plating.
PICKLE VINEGAR: See Vinegar.
PICKLING OF GERMAN-SILVER ARTICLES: See Plating.
PICKLING IRON SCRAP BEFORE ENAMELING: See Enameling.
PICRIC ACID STAINS, TO REMOVE: See Cleaning Preparations and Methods.
PICTURE COPYING: See Copying.
PICTURE FRAMES, REPAIRING: See Adhesives and Lutes.
PICTURE POSTAL CARDS: See Photography.
«Pigments»
(See also Paints.)
«Nature, Source, and Manufacture of Pigments.»—A pigment is a dry
earthy or clayey substance that, when mixed with oil, water, etc.,
forms a paint. Most pigments are of mineral origin, but there are
vegetable pigments, as logwood, and animal pigments, as cochineal.
In modern practice the colors are produced mainly by dyeing certain
clays, which excel in a large percentage of silicic acid, with aniline
dyestuffs. The coloring matters best adapted for this purpose are those
of a basic character. The colors obtained in this manner excel in a
vivid hue, and fastness to light and water.
Following is a general outline of their manufacture: One hundred parts,
by weight, of washed clay in paste form are finely suspended in 6 to 8
times the volume of water and acidulated with about 1 1/2 parts, by
volume, of 5 per cent hydrochloric or acetic acid, and heated by means
of steam almost to the boiling temperature. There is next introduced,
according to the shade desired, 1 to 2 parts, by weight, of the
dyestuff, such as auramin, diamond green, Victoria blue, etc., with
simultaneous stirring and heating, for 1 to 2 hours, or until a sample
filtered off from the liquor shows no dyestuff. Next the clay dyed in
this manner is isolated by filtration and washed with hot water and
dried. The colors thus obtained may be used as substitutes for mineral
colors of all description.
The method of manufacture varies greatly. According to the Bennett and
Mastin English patent the procedure is as follows: Grind together to
a paste in water, substances of a clayey, stony, earthy, or vitreous
nature, and certain metallic oxides, or “prepared oxides,” such as are
commonly used in the pottery trades; dry and powder the paste, and
subject the powder to the heat of a furnace, of such a temperature
that the requisite color is obtained, and for such length of time
that the color strikes through the whole substance. For example, 8
parts of black oxide of cobalt, 12 parts of oxide of zinc, and 36
parts of alumina, when incorporated with 20 times their combined bulk
of clay and treated as described, yield a rich blue pigment in the
case of a white clay, and a rich green in the case of a yellow clay.
Long-continued firing in this case improves the color.
Many minerals included in formulas for pigments have little or no
coloring power in themselves; nevertheless they {556} are required in
producing the most beautiful shades of color when blended one with
another, the color being brought out by calcination.
«Mixing Oil Colors and Tints.»—It must not be expected that the
formulas given will produce the exact effect desired, because the
strength of the various brands of colors vary to a great extent, and
therefore the painter must exercise his own judgment. The table simply
gives an idea of what can be produced by following the formulas given,
when chemically pure material is employed in the mixing. It is also
recommended that the parts mentioned be weighed out in paste form,
and the white or black and each color separately thinned and strained
before mixing them together, because the arriving at the proper hue
of color or depth and tone of tint will be simplified by using that
precaution. By thinning it is not meant that they should be quite
ready for application, but of such consistency that they will pass an
ordinary strainer with the aid of a brush.
Unless otherwise indicated, the materials are understood to be ground
fine in paste form.
NOTE.—The majority of the following are by Joseph Griggs, in the
_Painters’ Magazine_:
«GROUNDS FOR GRAINING COLORS:»
Ash Ground.—Four hundred parts white lead; 4 parts French ocher; 1 part
raw Turkey umber.
Ash.—Raw umber; raw sienna; and a little black or Vandyke brown.
Hungarian Ash.—Raw sienna and raw and burnt umber.
Bun Ash.—Raw sienna; burnt umber; and Vandyke brown.
Cherry Ground.—One hundred parts white lead; 5 parts burnt sienna; 1
part raw sienna.
Natural Cherry.—Raw and burnt sienna and raw umber.
Stained Cherry.—Burnt sienna; burnt umber; and Vandyke brown.
Chestnut.—Raw sienna; burnt umber; Vandyke brown; and a little burnt
sienna.
Maple.—Raw sienna and raw umber.
Silver Maple.—Ivory black over a nearly white ground.
Light Maple Ground.—One hundred parts white lead; 1 part French ocher.
Dark Maple Ground.—One hundred parts white lead; 1 part dark golden
ocher.
Oak.—Raw sienna; burnt umber; a little black.
Pollard Oak.—Raw and burnt sienna, or burnt umber and Vandyke brown.
Light Oak Ground.—Fifty parts white lead; 1 part French ocher.
Dark Oak Ground.—Fifty parts white lead; 1 part dark golden ocher.
Satinwood.—Add a little ivory black to maple color.
Mahogany.—Burnt sienna; burnt umber; and Vandyke brown.
Mahogany Ground.—Ten parts white lead; 5 parts orange chrome; and 1
part burnt sienna.
Rosewood.—Vandyke brown and a little ivory black.
Rosewood Ground.—Drop black.