Chapter I: II III (7)

The instruments used are an objective of very short focus and a small 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.

Walnut Ground.—Fifty parts white lead; 3 parts dark golden ocher; 1 part dark Venetian red; and 1 part drop black.

Black Walnut.—Burnt umber with a little Vandyke brown for dark parts.

French Burl Walnut.—Same as black walnut.

Hard Pine.—Raw and burnt sienna; add a little burnt umber.

Cypress.—Raw and burnt sienna and burnt umber.

Whitewood.—Ground same as for light ash; graining color, yellow ocher, adding raw umber and black for dark streaks.

«POSITIVE COLORS:»

Blue.—Twelve parts borate of lime; 6 parts oxide of zinc; 10 parts litharge; 9 parts feldspar; 4 parts oxide of cobalt.

Blue Black A.—Nine parts lampblack; 1 part Chinese or Prussian blue.

Blue Black B.—Nineteen parts drop black; 1 part Prussian blue.

Bright Mineral.—Nine parts light Venetian red; 1 part red lead.

Brilliant Green.—Nine parts Paris green; 1 part C. C. chrome green, light.

Bronze Green, Light.—Three parts raw Turkey umber; 1 part medium chrome yellow.

Bronze Green, Medium.—Five parts medium chrome yellow; 3 parts burnt Turkey umber; 1 part lampblack.

Bronze Green, Dark.—Twenty parts drop black; 2 parts medium chrome yellow; and 1 part dark orange chrome. {557}

Bottle Green.—Five parts commercial chrome green, medium, and 1 part drop black.

Brown.—Ten parts crude antimony; 12 parts litharge; 2 parts manganese; 1 part oxide of iron.

Brown Stone.—Eighteen parts burnt umber; 2 parts dark golden ocher; and 1 part burnt sienna.

Cherry Red.—Equal parts of best imitation vermilion and No. 40 carmine.

Citron A.—Three parts medium chrome yellow and 2 parts raw umber.

Citron B.—Six parts commercial chrome green, light, and 1 part medium chrome yellow.

Coffee Brown.—Six parts burnt Turkey umber; 2 parts French ocher; and 1 part burnt sienna.

Emerald Green.—Use Paris green.

Green.—Twenty parts litharge; 12 parts flint; 2 parts oxide of copper; 2 1/2 parts ground glass; 2 1/2 parts whiting; 1 1/2 parts oxide of chrome.

Flesh Color.—Nineteen parts French ocher; 1 part deep English vermilion.

Fern Green.—Five parts lemon chrome yellow and 1 part each of light chrome green and drop black.

Foliage Green.—Three parts medium chrome yellow and 1 part of ivory or drop black.

Foliage Brown.—Equal parts of Vandyke brown and orange chrome yellow.

Golden Ocher.—Fourteen parts French yellow ocher and 1 part medium chrome yellow for the light shade, and 9 parts Oxford ocher and 1 part orange chrome yellow for the dark shade.

Gold Russet.—Five parts lemon chrome yellow and 1 part light Venetian red.

Gold Orange.—Equal parts of dry orange mineral and light golden ocher in oil.

Indian Brown.—Equal parts of light Indian red, French ocher, and lamp black

Mahogany, Cheap.—Three parts dark golden ocher and 1 part of dark Venetian red.

Maroon, Light.—Five parts dark Venetian red; 1 part drop black.

Maroon, Dark.—Nine parts dark Indian red; 1 part lampblack.

Olive Green.—Seven parts light golden ocher; 1 part drop black.

Ochrous Olive.—Nine parts French ocher; 1 part raw umber.

Orange-Brown.—Equal parts burnt sienna and orange chrome yellow.

Oriental Red.—Two parts Indian red, light, in oil; 1 part dry red lead.

Purple A.—Eight parts crocus martis; 2 parts red hematite; 1 part oxide of iron.

Purple B.—Two parts rose pink; 1 part ultramarine blue.

Purple Black.—Three parts lampblack and 1 part rose pink, or 9 parts drop black and 1 part rose pink.

Purple Brown.—Five parts Indian red, dark, and 1 part each of ultramarine blue and lampblack.

Roman Ocher.—Twenty-three parts French ocher and 1 part each burnt sienna and burnt umber.

Royal Blue, Dark.—Eighteen parts ultramarine blue and 2 parts Prussian blue. To lighten use as much white lead or zinc white as is required.

Royal Purple.—Two parts ultramarine blue; 1 part No. 40 carmine or carmine lake.

Russet.—Fourteen parts orange chrome yellow and 1 part C. P. chrome green, medium.

Seal Brown.—Ten parts burnt umber; 2 parts golden ocher, light; 1 part burnt sienna.

Snuff Brown.—Equal parts burnt umber and golden ocher, light.

Terra Cotta.—Two parts white lead; 1 part burnt sienna; also 2 parts French ocher to 1 part Venetian red.

Turkey Red.—Strong Venetian red or red oxide.

Tuscan Red. Ordinary.—Nine parts Indian red to 1 part rose pink.

Brilliant.—Four parts Indian red to 1 part red madder lake.

Violet.—Three parts ultramarine blue; 2 parts rose lake; 1 part best ivory black.

Yellow.—Four and one-half parts tin ashes; 1 part crude antimony; 1 part litharge; and 1 part red ocher.

Yellow, Amber.—Ten parts medium chrome yellow; 7 parts burnt umber; 3 parts burnt sienna.

Yellow, Canary.—Five parts white lead; 2 parts permanent yellow; 1 part lemon chrome yellow.

Yellow, Golden.—Ten parts lemon chrome yellow; 3 parts orange chrome, dark; 5 parts white lead.

Yellow, Brimstone.—Three parts white lead; 1 part lemon chrome yellow; 1 part permanent yellow. {558}

Azure Blue.—Fifty parts white lead; 1 part ultramarine blue.

Blue Gray.—One hundred parts white lead; 3 parts Prussian blue; 1 part lampblack.

Bright Blue.—Twenty parts zinc white; 1 part imitation cobalt blue.

Blue Grass.—Seven parts white lead; 2 parts Paris green; 1 part Prussian blue.

Deep Blue.—Fifteen parts white lead; 1 part Prussian blue or Antwerp blue.

French Blue.—Five parts imitation cobalt blue; 2 parts French zinc white.

Green Blue.—One hundred parts white lead; 5 parts lemon chrome yellow; 3 parts ultramarine blue.

Hazy Blue.—Sixty parts white lead; 16 parts ultramarine blue; 1 part burnt sienna.

Mineral Blue.—Five parts white lead; 4 parts imitation cobalt blue; 2 parts red madder lake; 1 part best ivory or drop black.

Orient Blue.—Twenty-five parts white lead; 2 parts Prussian blue; 1 part lemon chrome yellow.

Royal Blue.—Thirty-four parts white lead; 19 parts ultramarine blue; 2 parts Prussian blue; 1 part rose madder or rose lake.

Sapphire Blue.—Two parts French zinc white and 1 part best Chinese blue.

Sky Blue.—One hundred parts white lead; 1 part Prussian blue.

Solid Blue.—Five parts white lead; 1 part ultramarine blue.

Turquoise Blue.—Twenty parts white lead; 3 parts ultramarine blue; 1 part lemon chrome yellow.

«RED TINTS:»

Cardinal Red.—Equal parts of white lead and scarlet lake.

Carnation Red.—Fifteen parts white lead; 1 part scarlet lake.

Claret.—Twenty-one parts oxide of zinc; 4 parts crocus martis; 4 parts oxide of chrome; 3 parts red lead; 3 parts boracic acid.

Coral Pink.—Fifteen parts white lead; 2 parts bright vermilion; 1 part deep orange chrome.

Deep Rose.—Ten parts white lead; 1 part red lake.

Deep Purple.—Five parts white lead; 1 part ultramarine blue; 1 part rose pink.

Deep Scarlet.—Fifteen parts bright vermilion; 2 parts red lake; 5 parts white lead.

Flesh Pink.—One hundred parts white lead; 1 part orange chrome yellow; 1 part red lake.

Indian Pink.—One hundred parts white lead; 1 part light Indian red.

Lavender.—Fifty parts white lead; 2 parts ultramarine blue; 1 part red lake.

Light Pink.—Fifty parts white lead; 1 part bright vermilion.

Lilac.—Fifty parts white lead; 1 part best rose pink.

Mauve.—Fifteen parts white lead; 2 parts ultramarine blue; 1 part carmine lake or red lake.

Orange Pink.—Two parts white lead; 1 part dark orange chrome or American vermilion.

Purple.—Five parts white lead; 2 parts ultramarine blue; 1 part red madder lake.

Royal Pink.—Five parts white lead; 1 part carmine lake or red madder lake.

Royal Rose.—Twenty parts white lead; 1 part rich rose lake.

Red Brick.—Ten parts white lead; 3 parts light Venetian red; 1 part yellow ocher.

Reddish Terra Cotta.—Two parts white lead; 1 part rich burnt sienna.

Salmon.—Fifty parts white lead; 5 parts deep orange chrome.

Shell Pink.—Fifty parts white lead; 2 parts bright vermilion; 1 part orange chrome; 1 part burnt sienna.

Violet.—Fifteen parts white lead; 4 parts ultramarine blue; 3 parts rose lake; 1 part drop black.

«GREEN TINTS:»

Apple Green.—Fifty parts white lead; 1 part chrome green, light or medium shade.

Citrine Green.—One hundred parts white lead; 2 parts medium chrome yellow; 1 part drop black.

Citron Green.—One hundred parts white lead; 3 parts medium chrome yellow; 1 part lampblack.

Emerald Green.—Ten parts white lead; 1 part Paris (emerald) green.

Grass Green A.—Five parts white lead; 7 parts Paris green.

Grass Green B.—Ten parts oxide of chrome; 2 parts tin ashes; 5 parts whiting; 1 part crocus martis; 1 part bichromate potash.

Gray Green.—Five parts white lead; 1 part Verona green. {559}

Marine Green.—Ten parts white lead; 1 part ultramarine green.

Nile Green.—Fifty parts white lead; 6 parts medium chrome green; 1 part Prussian blue.

Olive Green.—Fifty parts white lead; 2 parts medium chrome yellow; 3 parts raw umber; 1 part drop black.

Olive Drab.—Fifty parts white lead; 8 parts raw umber; 5 parts medium chrome green; 1 part drop black.

Pea Green.—Fifty parts white lead; 1 part light chrome green.

Satin Green.—Three parts white lead; 1 part Milori green.

Sage Green.—One hundred parts white lead; 3 parts medium chrome green; 1 part raw umber.

Sea Green.—Fifty parts white lead; 1 part dark chrome green.

Stone Green.—Twenty-five parts white lead; 2 parts dark chrome green; 3 parts raw umber.

Velvet Green.—Twenty parts white lead; 7 parts medium chrome green; 2 parts burnt sienna.

Water Green.—Fifteen parts white lead; 10 parts French ocher; 1 part dark chrome green.

«BROWN TINTS:»

Chocolate.—Twenty-five parts white lead; 3 parts burnt umber.

Cocoanut.—Equal parts white lead and burnt umber.

Cinnamon.—Ten parts white lead; 2 parts burnt sienna; 1 part French ocher.

Dark Drab.—Forty parts white lead; 1 part burnt umber.

Dark Stone.—Twenty parts white lead; 1 part raw umber.

Fawn.—Fifty parts white lead; 3 parts burnt umber; 2 parts French ocher.

Golden Brown.—Twenty-five parts white lead; 4 parts French ocher; 1 part burnt sienna.

Hazel Nut Brown.—Twenty parts white lead; 5 parts burnt umber; 1 part medium chrome yellow.

Mulberry.—Ten parts manganese; 2 parts cobalt blue; 2 parts saltpeter.

Purple Brown.—Fifty parts white lead; 6 parts Indian red; 2 parts ultramarine blue; 1 part lampblack.

Red Brown.—Twelve parts hematite ore; 3 parts manganese; 7 parts litharge; 2 parts yellow ocher.

Seal Brown.—Thirty parts white lead; 5 parts burnt umber; 1 part medium chrome yellow.

Snuff Brown.—Twenty-five parts white lead; 1 part burnt umber; 1 part Oxford ocher.

«GRAY TINTS:»

Ash Gray.—Thirty parts white lead; 2 parts ultramarine blue; 1 part burnt sienna.

Cold Gray.—Five hundred parts white lead; 6 parts lampblack; 1 part Antwerp blue.

Dove Color.—Twelve parts manganese; 5 parts steel filings; 3 parts whiting; 1 part oxide of cobalt.

Dove Gray.—Two hundred parts white lead; 5 parts ultramarine blue; 2 parts drop black.

French Gray.—One hundred and fifty parts white lead; 2 parts lampblack; 1 part orange chrome yellow; 1 part chrome red (American vermilion).

Lead Color.—Fifty parts white lead; 1 part lampblack (increase proportion of white lead for light tints).

Lustrous Gray.—Ten parts white lead; 1 part graphite (plumbago).

Olive Gray.—Two hundred parts white lead; 2 parts lampblack; 1 part medium chrome green.

Pure Gray.—One hundred parts white lead; 1 part drop black.

Pearl Gray.—One hundred parts white lead; 1 part ultramarine blue; 1 part drop black.

Silver Gray.—One hundred and fifty parts white lead; 2 parts lampblack; 3 parts Oxford ocher.

Warm Gray.—One hundred parts white lead; 3 parts drop black; 2 parts French ocher; 1 part light Venetian red.

NOTE.—For inside work and whenever desirable, the white lead may be replaced by zinc white or a mixture of the two white pigments may be used. Be it also remembered that pure colors, as a rule, will produce the cleanest tints and that fineness of grinding is an important factor. It will not be amiss to call attention to the fact that the excessive use of driers, especially of dark japans or liquid driers, with delicate tints is bad practice, and liable to ruin otherwise good effects in tints or delicate solid colors.

«COLOR TESTING.»

Expense and trouble deter many a painter from having a color examined, {560} although such an examination is often very necessary. For the practical man it is less important to know what percentage of foreign matter a paint contains, but whether substances are contained therein, which may act injuriously in some way or other.

If a pigment is to be tested for arsenic, pour purified hydrochloric acid into a test tube or a U-shaped glass vessel which withstands heat, add a little of the pigment or the colored fabric, wall paper, etc. (of pigment take only enough to strongly color the hydrochloric acid simply in the first moment), and finally a small quantity of stannous chloride. Now heat the test tube with its contents moderately over a common spirit lamp. If the liquid or mass has assumed a brown or brownish color after being heated, arsenic is present in the pigment or fabric, etc.

An effective but simple test for the durability of a color is to paint strips of thick paper and nail them on the wall in the strongest light possible. A strip of paper should then be nailed over one-half of the samples of color so as to protect them from the light. On removing this the difference in shade between the exposed and unexposed portions will be very apparent. Some colors, such as the vermilionettes, will show a marked difference after even a few weeks.

«Testing Body Colors for Gritty Admixtures.»—The fineness of the powdered pigment is not a guarantee of the absence of gritty admixtures. The latter differ from the pigment proper in their specific gravity. If consisting of metallic oxides or metallic sulphides the sandy admixtures are lighter than the pigments and rise to the surface upon a systematic shaking of the sample. In the case of other pigments, e. g., aluminas and iron varnish colors, they collect at the bottom. For carrying out the test, a smoothly bored metallic tube about 1/2 to 3/4 inch in diameter and 6 to 7 inches long is used. Both ends are closed with screw caps and at one side of the tube some holes about 1/6 of an inch in diameter are bored, closed by pieces of a rubber hose pushed on. The tube is filled with the pigment powder, screwed up and feebly shaken for some time in a vertical position (the length of time varying according to the fineness of the powder). Samples may now be taken from all parts of the tube. Perhaps glass tubes would be preferable, but lateral apertures cannot be so readily made. After the necessary samples have been collected in this manner, they must be prepared with a standard sample, which is accomplished either by feeling the powder between the fingers or by inspecting it under a microscope, or else by means of the scratching test, which last named is the usual way. The requisites for these scratch tests consist of two soft, well-polished glass plates (2 1/2 x 2 1/4 inches) which are fixed by means of cement in two stronger plates of hard wood suitably hollowed out. The surface of the glass must project about 1/2 inch over the wooden frame. If a sample of the pigment powder is placed on such a glass plate, another plate is laid on top and both are rubbed slowly together; this motion will retain a soft, velvety character in case the pigment is free from gritty admixtures; if otherwise, the glass is injured and a corresponding sound becomes audible. Next the powder is removed from the plate, rubbing the latter with a soft rag, and examining the surface with a microscope. From the nature of the scratches on the plate the kind of gritty ingredients can be readily determined. The human finger is sufficiently sensitive to detect the presence of gritty substances, yet it is not capable of distinguishing whether they consist of imperfectly reduced or badly sifted grains of pigment or real gritty admixtures.

«To Determine the Covering Power of Pigments.»—To determine the covering power of white lead, or any other pigment, take equal quantities of several varieties of white lead and mix them with a darker pigment, black, blue, etc., the latter also in equal proportions. The white lead which retains the lightest color is naturally the most opaque. In a similar manner, on the other hand, the mixing power of the dark pigments can be ascertained. If experiments are made with a variety of white lead or zinc white, by the admixture of dark pigments, the color which tints the white lead or zinc white most, also possesses the greatest covering or mixing power.

«To Detect the Presence of Aniline in a Pigment.»—Lay a little of the color upon letter paper and pour a drop of spirit on it. If it is mixed with aniline the paper is colored right through thereby, while a pure pigment does not alter the shade of the paper and will never penetrate it.

«Vehicle for Oil Colors.»—Petroleum, 20 to 30 pounds; tallow, 3 to 5 pounds; cotton-seed oil, 5 to 7 pounds; colophony, 5 to 7 pounds. The pigments {561} having been ground up with this mixture, the mixed paint can be made still better by adding to it about a sixth of its weight of the following mixture: Vegetable oil, 8 to 20 pounds; saponified rosin, 6 to 16 pounds; turpentine, 4 to 30 ounces.

«Frankfort Black.»—Frankfort black, also known as German black, is a name applied to a superior grade of lampblack. In some districts of Germany it is said to be made by calcining wine lees and tartar. The material is heated in large cylindrical vessels having a vent in the cover for the escape of smoke and vapors that are evolved during the process. When no more smoke is observed, the operation is finished. The residuum in the vessels is then washed several times in boiling water to extract the salts contained therein and finally is reduced to the proper degree of fineness by grinding on a porphyry.

«Paris Green.»—Emerald or Paris green is rather permanent to light, but must not be mixed with pigments containing sulphur, because of the tendency to blacken when so mixed. It will not resist acids, ammonia, and caustics.

PIGMENT PAPER: See Photography.

«PILE OINTMENTS.»

I.—“Extract” witch-hazel 2 fluidounces
Lanum 2 ounces
Petrolatum 6 ounces
Glycerine 4 fluidounces
Tannic acid 1 drachm
Powdered opium 1 drachm

II.—Tannic acid 20 grains
Bismuth subnitrate 1 drachm
Powdered opium 10 grains
Lanum 3 drachms
Petrolatum 5 drachms

PINE SYRUP: See Essences and Extracts.

PINEAPPLE ESSENCE: See Essences and Extracts.

PINEAPPLE LEMONADE: See Beverages.

PING PONG FRAPPÉ: See Beverages, under Lemonades.

PINS OF WATCHES: See Watchmakers’ Formulas.

PINION ALLOY: See Watchmakers’ Formulas.

PINK SALVE: See Ointments.

PINKEYE: See Veterinary Formulas.

PIPE-JOINT CEMENT: See Cement.

PIPE LEAKS: See Leaks.

PIPES, RUST-PREVENTIVE FOR: See Rust Preventives.

PISTACHIO ESSENCE: See Essences and Extracts.

«PLANTS:»

«Temperature of Water for Watering Plants.»—Experiments were made several years ago at the Wisconsin Agricultural Experiment Station to determine whether cold water was detrimental to plants. Plants were grown under glass and in the open field, and in all cases the results were similar. Thus, coleus planted in lots of equal size and vigor were watered with water at 35°, 50°, 65°, and 86° F. At the end of 60 days it was impossible to note any difference, and when the experiment was repeated with water at 32°, 40°, 70°, and 100° F., the result was the same. Beans watered with water at 32°, 40°, 70°, and 100° F., were equally vigorous; in fact, water at 32° and 40° F. gave the best results. Lettuce watered with water at 32° F. yielded slightly more than the other lots. From these experiments it was concluded that for vegetable and flowering plants commonly grown under glass, ordinary well or spring water may be used freely at any time of the year without warming.

PLANT PRESERVATIVES: See Flowers.

«Plaster»

(See also Gypsum.)

«Therapeutic Grouping of Medicinal Plasters.»—The vehicle for medicated plasters requires some other attribute than simply adhesiveness. From a study of the therapy of plasters they may be put in three groups, similarly to the ointments with reference to their general therapeutic uses, which also governs the selection of the respective vehicles.

1.—Epidermatic: Supportive, protective, antiseptic, counter-irritant, vesicant. Vehicle: Rubber or any suitable {562} adhesive. Official plasters: Emp. adhesivum, E. capsici.

2.—Endermatic: Anodyne, astringent, alterative, resolvent, sedative, stimulant. Vehicle: Oleates or lead plaster, sometimes with rosins or gum rosins. Official plasters: Emp. Belladonnæ, E. opii, E. plumbi, E. saponis.

3.—Diadermatic: For constitutional or systemic effects. Vehicle: Lanolin or plaster-mull. Official plasters: Emp. hydrargyri.

«Methods of Preparing Rubber Plasters.—Mechanic Roller Pressure Method.»—This method of incorporating the rubber with certain substances to give it the necessary body to serve as a vehicle is at present the only one employed. But since it requires the use of the heaviest machinery—some of the apparatus weighing many tons—and enormous steam power, its application for pharmaceutical purposes is out of the question.

As is well known, the process consists in: 1. Purification of the rubber by mascerating and pressing it and removing foreign impurities by elutriating it with water. 2. Forming a homogeneous mass of the dried purified rubber by working it on heated revolving rollers and incorporating sufficient quantities of orris powder and oleoresins. 3. Incorporating the medicinal agent, i. e., belladonna extract, with the rubber mass by working it on warmed revolving rollers. 4. Spreading the prepared piaster.

Solution in Volatile Solvents.—This process has been recommended from time to time, the principal objection being the use of so relatively large quantities of inflammable solvents.

«The German Pharmacopœia Method.»—The following is the formula of “Arzneibuch fur das Deutsche Reich,” 1900: Emplastrum adhesivum: Lead plaster, waterfree, 40 parts; petrolatum, 2.5 parts; liquid petrolatum, 2.5 parts, are melted together, and to the mixture add rosin, 35 parts; dammar, 10 parts, previously melted. To the warm mixture is added caoutchouc, 10 parts; dissolved in benzine, 75 parts, and the mixture stirred on the water-bath until all the benzine is lost by evaporation.

The Coleplastrum adhesivum of the Austrian Society is still more complex, the formula containing the following: Rosin oil, empyreumatic, 150 parts; copaiba, 100 parts; rosin, 100 parts; lard, 50 parts; wax, 30 parts; dissolved in ether, 1,200 parts, in which caoutchouc, 250 parts, has been previously dissolved; to this is then added orris powder, 220 parts; sandarac, 50 parts; ether, 400 parts. The mixture, when uniform, is spread on cloth.

«Solution of Rubber in Fixed Solvent: Petrolatum and Incorporation with Lead Acetate.»—India rubber dissolves, though with difficulty, in petrolatum. The heat required to melt the rubber being comparatively high, usually considerably more than 212° F., as stated in the U. S. P., it is necessary to melt the rubber first and then add the petrolatum, in order to avoid subjecting the latter to the higher temperature. The mixture of equal parts of rubber and petrolatum is of a soft jelly consistence, not especially adhesive, but when incorporated with the lead oleate furnishes a very adhesive plaster. While at first 5 per cent of each rubber and petrolatum was used, it has been found that the petrolatum would melt and exude around the edges of the plaster when applied to the skin, and the quantity was therefore reduced to 2 per cent of each. This mass affords a plaster which is readily adhesive to the body, does not run nor become too soft. Plasters spread on cloth have been kept for months exposed to the sun in the summer weather without losing their stability or permanency.

The lead oleate made by the interaction of hot solution of soap and lead acetate, thoroughly washed with hot water, and freed from water by working the precipitated oleate on a hot tile, is much to be preferred to the lead plaster made by the present official process. The time-honored method of boiling litharge, olive oil, and water is for the requirements of the pharmacists most tedious and unsatisfactory. Since in the beginning of the process, at least, a temperature higher than that of 212° F. is required, the water bath cannot be employed, and in the absence of this limiting device the product is usually “scorched.” When the steam bath under pressure can be used this objection does not apply. But the boiling process requires from 3 to 4 hours, with more or less attention, while the precipitation method does not take over half an hour. Besides, true litharge is difficult to obtain, and any other kind will produce unsatisfactory results.

The following is the process employed:

Lead oleate (Emplastrum plumbi):

Soap, granular and dried 100 parts Lead acetate 60 parts Distilled water, a sufficient quantity.

{563}

Dissolve the soap in 350 parts hot distilled water and strain the solution. Dissolve the lead acetate in 250 parts hot distilled water and filter the solution while hot into the warm soap solution, stirring constantly. When the precipitate which has formed has separated, decant the liquid and wash the precipitate thoroughly with hot water. Remove the precipitate, let it drain, free from water completely by kneading it on a warm slab, form it into rolls, wrap in paraffine paper, and preserve in tightly closed containers.

Emplastrum adhesivum:

Rubber, cut in small pieces 20 parts Petrolatum 20 parts Lead plaster 960 parts

Melt the rubber at a temperature not exceeding 302° F., add the petrolatum, and continue the heat until the rubber is dissolved. Add the lead plaster to the hot mixture, continue the heat until it becomes liquid; then let it cool and stir until it stiffens.

«Court Plaster or Sticking Plaster.»—I.—Brush silk over with a solution of isinglass, in spirits or warm water, dry and repeat several times. For the last application apply several coats of balsam of Peru. This is used to close cuts or wounds, by warming and applying it. It does not wash off until the skin partially heals.

II.—Isinglass, 1 part; water, 10 parts; dissolve, strain the solution, and gradually add to it of tincture of benzoin, 2 parts; apply this mixture gently warmed, by means of a camel’s-hair brush, to the surface of silk or sarcenet, stretched on a frame, and allow each coating to dry before applying the next one, the application being repeated as often as necessary; lastly, give the prepared surface a coating of tincture of benzoin or tincture of balsam of Peru. Some manufacturers apply this to the unprepared side of the plaster, and others add to the tincture a few drops of essence of ambergris or essence of musk.

III. (Deschamps).—A piece of fine muslin, linen, or silk is fastened to a flat board, and a thin coating of smooth, strained flour paste is given to it; over this, when dry, two coats of colorless gelatin, made into size with water, quantity sufficient, are applied warm. Said to be superior to the ordinary court plaster.