The Project Gutenberg EBook of A Practical Manual of the Collodion Process, Giving in Detail a Method For Producing Positive and Negative Pictures on Glass and Paper., by Samuel Dwight Humphrey This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.org/license Title: A Practical Manual of the Collodion Process, Giving in Detail a Method For Producing Positive and Negative Pictures on Glass and Paper. Author: Samuel Dwight Humphrey Release Date: October 21, 2020 [EBook #63517] Language: English Character set encoding: ISO-8859-1 *** START OF THIS PROJECT GUTENBERG EBOOK A PRACTICAL MANUAL OF THE *** Produced by Tom Cosmas produced from files generously provided on The Internet Archive. All resultant materials are placed in the Public Domain. HUMPHREY'S JOURNAL OF THE DAGUERREOTYPE AND PHOTOGRAPHIC ARTS. The above-named Publication is well known as the best and most valuable one devoted to the Photographic Science in this country. Humphrey's Journal made its first appearance Nov. 1st, 1850, and consequently is the first and oldest serial offered to the Photographic world. The art of producing Portraits and Landscapes by means of Light has recently taken a new and enlivening impulse, which will in all probability lead to important and interesting results. No practical Daguerreotypist, Photographer, or amateur should be without the means at hand for securing all of the information upon this subject. Each should be ready to receive and apply the improvements as they may be developed. In order to accomplish this, it is a matter of great importance to the Practitioner or Experimenter that he should have a reliable medium through which he can obtain information. In what source can the inquirer better place his confidence than in a regular Journal, whose editor is literally a practical person, and familiar with the manipulations necessary for producing Portraits upon "Daguerreotype Plates," and upon glass and paper? Such is the conductor of Humphrey's Journal. This Journal is published once every two weeks, and contains all the improvements relating to the Art, and is the only American Journal whose editor is practically acquainted with the process for producing Daguerreotypes. Ambrotypes, and Photographs The first No. of Vol. VIII is dated May 1st, 1856. The terms (Two Dollars per annum) are trifling compared with the vast amount of information furnished. There are several societies recently established in Europe composed of learned and scientific men, who are in every way engaged in investigating the Science, and we may look for improvement from that quarter, as well as from our numerous resources at home. In the former case our facilities for early and reliable information cannot well be surpassed. Ambrotypes.—Humphrey's Journal contains everything novel which appears upon this subject, and has already presented more new, important; and original matter than can be found in any other place. Many are the letters we have received during the term of the last volume, in which the writer has stated that a single number of Humphrey's Journal has contained information of more value to him than "several times the amount paid for the entire volume." Our resources have grown up around us, and our facilities for procuring, as well as distributing, all such facts and improvements as will benefit as well as instruct all who have the progress of the Art at heart, are as ample as they can well be made. The future volumes will be abundantly furnished with original writings from persons of standing in the scientific world; and the practical Photographer will here find a full account of such improvements as may from time to time develope themselves. [-i-] [-ii-] From the Editor's long practical experience in the Heliographic Science, he will be enabled to present the subject in a plain, clear and concise manner. Read what the Editors say of Humphrey's Journal:— "We have received a copy of a valuable Journal (Humphrey's) published in New York, which has reached the 18th number of Vol. VI. ... We now have the pleasure of quoting from our transatlantic coadjutor."—Liverpool Photographic Jour. "Humphrey's Journal is practical as Well as scientific in character."—American Journal of Science and Arts. "It treats the subject knowingly, and with force."—New York Tribune. "It is both a popular and interesting publication."—Mechanics' Magazine. "It is highly useful to all who practice 'shadow catching.'"—Ohio State Journal. "The work is neatly gotten up, and contains many interesting varieties in this new field of science."—Times. "It should be hailed and encouraged, not only by Daguerreotypists themselves, but by every lover of Science and Art."—The Democrat. "We cannot too strongly urge all artists, and those persons who feel an interest in the Heliographic Arts and Sciences, to take a copy of the work."—Sentinel. "It is indicative of talent worthy of the important Art it is designed to elevate."—American. "This Art is entitled to its own organ, which could not have fallen into better hands than those of the editor of Humphrey's Journal."—Transcript. "It is a scientific work of interest and usefulness."—Star of the North. "This Journal answers many points heretofore regarded as inexplicable."—Hudson River Chronicle. "It is rich with interest."—North American. "It contains all the 'Improvements.'"—Delta. "It teaches us how to take our own portraits."—Bee. "It will cultivate a taste for Daguerreotypes."—Commercial Advertiser. "It should be in the hands of all."—Reveille. "It is the Daguerreotypist's friend."—London News. "It should be found in every library."—Evening Journal. From some of our old subscribers. "Humphrey's Journal has been the means of saving much time and money, for by its instruction I have been enabled to produce some of the finest Paper Pictures I have ever seen." W. P. "Don't fail to send me the Journal, for I would not be without it for five times the amount of subscription. It is the only publication I can depend upon." A. G. R. "Your treatment of the humbugs and humbugging members of the profession, is of the most valuable importance to us practical Daguerreians. Go on. God speed! Here is the amount for the renewal of my subscription." E. F. S. "How can any Operator afford to be without it?" L. L. H. "Here is five dollars: send me Humphrey's Journal to this amount. I will not be without it." M. S. "It is my best friend." J. E. W. We might quote like commendatory extracts enough to more than ten times fill this page. Humphrey's Journal contains 16 octavo pages of reading matter. TERMS. One copy per annum,in advance$2 00 Three copies,do. do. 5 00 Six copies, do. do. 9 00 The thousands who read it cannot be induced to remain without it. All who desire to keep up with the improvements should subscribe for a copy. Subscription price Two Dollars per year. Don't fail to become a subscriber. Address S. D, HUMPHREY, NEW YORK. [Office, 37 Lispenard Street] A PRACTICAL MANUAL OF THE C O L L O D I O N P R O C E S S , GIVING IN DETAIL A METHOD FOR PRODUCING POSITIVE AND NEGATIVE P i c t u r e s o n G l a s s a n d P a p e r . [-iii-] [-iv-] [-v-] [-vi-] [-vii-] A M B R O T Y P E S . P R I N T I N G P R O C E S S . ALSO, PATENTS FOR THE COLLODION PROCESSES; MELAINOTYPES—PHOTOGRAPHS IN OIL—ALBUMENIZED COLLODION—CUTTING'S PATENTS AND CORRESPONDENCE.—SPECIFICATION'S OF ALL THE FOREGOING, GIVING EACH PROCESS ENTIRE. THIRD EDITION, REVISED AND GREATLY ENLARGED. By S. D. HUMPHREY. NEW YORK: HUMPHREY'S JOURNAL PRINT, 37 LISPENARD STREET. 1857. Entered according to Act of Congress, in the year 1857, by S. D. HUMPHREY, In the Clerk's Office of the District Court of the United States for the Southern District of New York. PREFACE TO THE THIRD EDITION. The rapid and unexpected sale of the entire second edition of this Manual has induced the author to lay the Third Edition before the Public. Although but little time has elapsed since the second, yet there have been some new developments which it has been thought best to give, as conducive to the interests of the practitioner. The manipulations have been given somewhat more in detail than in the Second Edition. All that would have a tendency to confuse the reader has been carefully avoided, and only the plain methods for operating laid down. The work is intended for the beginner in the glass process of producing Heliographic pictures. S. D. H. New York, February 1st, 1857. PREFACE TO THE FIRST EDITION. The object of this little Manual is to present, in as plain, clear and concise a manner as possible, the practice of a Collodion Process. This beautiful acquisition to a "sun-pencilling" was first given to the public by Mr. Frederick Scott Archer, an English gentleman, who alone is entitled to the credit, and deserves the esteem of every lover and practitioner of the Art, for his liberality in giving it to the world. The Process here presented has never before appeared in print, and has been practised with the most eminent success by those who have been enabled to adopt it. All reference to the various systems or methods of manipulation, by the thousands of practitioners, has been excluded, and one Process given. I conceived that this was the better plan to adopt, thus leaving the mind of the learner free from confusion, and pointing out one course, which, if carefully followed, will produce good and pleasing results. I have also presented a list of all Patents upon the Collodion Process; this will give all an opportunity of choosing their own course in regard to the respect they may conceive to be due to such Patent Rights. S. D. H. CONTENTS. PART I. CHAPTER I. Introduction—Light—Solar Spectrum—Decomposition of Light—Light—Heat and Actinism—Blue Paper and Color for the Walls of the Operating Room— Proportions of Light, Heat and Actinism composing a Sunbeam—Refraction—Reflection—Lenses—Copying—Spherical Aberration—Chromatic Aberration 13 CHAPTER II. Camera—Arrangement of Lenses—Camera Tubes—Camera Boxes, Bellows, and Copying—Camera Stands—Head Rests—Cleaning Vice—Nitrate Bath— Leveling Stands—Printing Frames—Collodion Vials 26 PART II. Practical Hints on Photographic Chemistry. CHAPTER III. [-viii-] [-ix-] [-x-] [-xi-] PRISM, SOLAR SPECTRUM. LIGHT, HEAT, AND ACTINISM. Soluble Cotton—Manipulation—Plain Collodion—Bromo-Iodized Collodion for Positives—Ditto for Negatives—Solution of Bromide and Iodide of Potassium and Silver—Double Iodide of Potassium and Silver—Developing Solution—Fixing the Solution—Brightening and Finishing the Image—Photographic Chemicals 41 PART III. Practical Details of the Positive or Ambrotype Process. CHAPTER IV. Lewis's Patent Vices for Holding the Glass—Cleaning and Drying the Glass—Coating—Exposure in the Camera—Developing—Fixing or Brightening—Backing up, &c. 129 PART IV. Practical Details of the Negative Process. CHAPTER V. Negative Process—Soluble Cotton—Plain Collodion—Developing Solution—Re-Developing Solution—Fixing the Image—Finishing the Image—Nitrate of Silver Bath 143 PART V. Practical Details of the Printing Process. CHAPTER VI. Printing Process—Salting Paper—Silvering Paper—Printing the Positive—Fixing and Coloring Bath—Mounting the Positive—Facts worth Knowing 151 CHAPTER VII. Helio Process.—An Entire Process for Producing Collodion Positives and Negatives with one Bath, and in much less time than by any other known Process: by Helio—Photographic Patents 164 CHAPTER VIII. The Collodio-Albumen Process in Detail 190 CHAPTER IX. On a Mode of Printing Enlarged and Reduced Positives, Transparencies, &c., from Collodion Negatives—On the Use of Alcohol for Sensitizing Paper—Recovery of Silver from Waste Solutions,—from the Black Deposit of Hypo Baths, &c.—The Salting and Albumenizing Paper—On the Use of Test Papers— Comparison of British and French Weights and Measures 191 PART I CHAPTER I. LIGHT—SOLAR SPECTRUM—DECOMPOSITION OF LIGHT—LIGHT, HEAT AND ACTINISM—BLUE PAPER AND COLOR FOR THE WALLS OF THE OPERATING ROOM—PROPORTIONS OF LIGHT, HEAT AND ACTINISM, COMPOSING A SUN-BEAM—REFRACTION— REFLECTION—LENSES—COPYING—SPHERICAL ABERRATION—CHROMATIC ABERRATION. It has been well observed by an able writer, that it is Impossible to trace the path of a sunbeam through our atmosphere without feeling a desire to know its nature, by what power it traverses the immensity of space, and the Various modifications it undergoes at the surfaces and the interior of terrestrial substances. Light is white and colorless, as long as it does not come in contact with matter. When in apposition with anybody it suffers variable degrees of decomposition, resulting in color, as, by reflection, dispersion, refraction and unequal absorption. To Sir I. Newton the world is indebted for proving the compound nature of a ray of white light emitted from the sun. The object of this work is not to engage in an extended theory upon the subject of light, but to recur only to some points-of more particular interest to the photographic operator. The decomposition of a beam of light can be noticed by exposing it to a prism. If, in a dark room, a beam of light be admitted through a small hole in a shutter 7 it will form a white round spot upon the place where it falls. If a triangular prism of glass be placed on the inside of the dark room, so that the beam of light falls upon it, it no longer has the same direction, nor does it form a round spot, but an oblong painted image of seven colors— red, orange, yellow, green, blue, indigo, and violet. This is called the solar spectrum, and will be readily understood by reference to the accompanying diagram, Fig. 1. Fig. 1. To those who are unacquainted with the theory of light (and for their benefit this chapter is given), it may be a matter of wonder how a beam of light can be divided. This can be understood when I say, that white light is a bundle of colored rays united together, and when so incorporated, they are colorless; but in passing through the prism the bond of union is severed, and the colored rays come out singly and separately, because each ray has a certain amount of refracting (bending) power, peculiar to itself. These rays always hold the same relation to each other, as may be seen by comparing every spectrum or rainbow; there is never any confusion or misplacement. There are various other means of decomposing white light besides the prism, of which one of the principal and most interesting to the photographer, is by reflection from colored bodies. If a beam of white light falls upon a white surface, it is reflected without change; but if it falls upon a red surface, only the red ray is reflected: so also with yellow and other colors; the ray which is reflected corresponds with the color of the object. It is this reflected decomposed light which presents the beautifully colored image we see upon the ground glass in our cameras. A sunbeam may be capable of three divisions—light, heat, and actinism; the last causes all the chemical changes, and is the acting power upon surfaces prepared to receive the photographic image. The accompanying illustration, Fig. 2, will readily bring to the minds of the reader the relation of these one to another, and their intensities in the different parts of a decomposed sunbeam. [-xii-] [-13-] [-14-] [-15-] COLORING WALLS BLUE. LIGHT, HEAT, AND CHEMICAL POWER. REFRACTION. REFRACTION, LENSES, FOCUS. Fig. 2. The various points of the solar spectrum are represented in the order in which they occur between A and B, this exhibits the limits of the Newtonian spectrum, corresponding with Fig. 1. Sir John Herschel and Seebeck have shown that there exists, beyond the violet, a faint violet light, or rather a lavender, to b, which gradually becomes colorless; similarly, red light exists beyond the assigned limits of the red ray to a. The greatest amount of actinic power is shown at E opposite the violet; hence this color "exerts" the greatest amount of influence in the formation of the photographic image. (Blue paper and blue color have been somewhat extensively used by our operators in their operating rooms and skylights, in order to facilitate the operation in the camera. I fancy, however, that this plan cannot be productive of as much good as thought by some, from the fact, that the light falling upon the subject, and then reflected into the camera, is, coming through colorless glass, not affected by such rays as may be reflected from the walls of the operating room; and even if it were so, I conceive that it would be injurious, by destroying the harmony of Shadows which might otherwise occur.) The greatest amount of white light is at C; the yellow contains less of the chemical power than any Other portion of the solar Spectrum. It has been found that the most intense heat is at the Extreme Red, b. Artificial lights differ in their color; the white light of turning charcoal, which is the principal light from candles, oil and gas, contains three fays—red, yellow and blue. The dazzling light emitted from lime intensely heated, known as the Drummond light, gives the color of the prism almost as bright as the solar spectrum. If we expose a prepared collodionized plate or sensitive paper to the solar spectrum, it will be observed that the luminous power (the yellow) occupies but a small space compared with the influence of heat and chemical power. R. Hunt, in his Researches on Light, has presented the following remarks upon the accompanying illustration:— Fig. 3. "If the linear measure, or the diameter of a circle which shall include the luminous rays, is 25, that of the calorific spectrum will be 42·10, and of the chemical spectrum 55·10. Such a series of circles may well be used to represent a beam from the sun, which may be regarded as an atom of Light surrounded with an invisible atmosphere of Heat, and another still more extended, which possesses the remarkable property of producing chemical and molecular change." A ray of light, in passing obliquely through any medium of uniform density, does not change its course; but if it should pass into a denser body, it would turn from a straight line, pursue a less oblique direction, and in a line nearer to a perpendicular to the surface of that body. Water exerts a stronger refracting power than air; and if a ray of light fall upon a body of this fluid its course is changed, as may be seen by reference to Fig. 4. It is observed that it proceeds in a less oblique direction (towards the dotted line), and, on passing on through, leaves the liquid, proceeding in a line parallel to that which it entered. It should be observed, that at the surface of bodies the refractive power is exerted, and that the light proceeds in a straight line until leaving the body. The refraction is more or less, and in all cases in proportion as the rays fall more or less obliquely on the refracting surface. It is this law of optics which has given rise to the lenses in our camera tubes, by which means we are enabled to secure a well-delineated representation of any object we choose to picture. Fig. 4. When a ray of light passes from one medium to another, and through that into the first again, if the two refractions be equal, and in opposite directions, no sensible effect will be produced. The reader may readily comprehend the phenomena of refraction, by means of light passing through lenses of different curves, by reference to the following diagrams:— [-16-] [-17-] [-18-] [-19-] ENLARGING OR REDUCING IN COPYING. LENSES. SPHERICAL ABERRATION. Fig. 5. Fig. 6. Fig. 7. Fig. 5 representing a double-convex lens, Fig. 6 a double-concave, and Fig. 7 a concavo-convex or meniscus. By these it is seen that a double-convex lens tends to condense the rays of light to a focus, a double-concave to scatter them, and a concavo-convex combines both powers. Fig. 8. Fig. 9. If parallel rays of light fall upon a double-convex lens, D D, Fig. 8, they will be refracted (excepting such as pass directly through the centre) to a point termed the principal focus. The lines A B C represent parallel rays which pass through the lens D D, and meet at F; this point being the principal focus, its distance from the lens is called the focal length. Those rays of light which are traversing a parallel course, when they enter the lens are brought to a focus nearer the lens than others. Hence the difficulty the operator sometimes experiences by not being able to "obtain a focus," when he wishes to secure a picture of some very distant objects; he does not get his ground glass near enough to the lenses. Again, the rays from an object near by may be termed diverging rays. This will be better comprehended by reference to Fig. 9, where it will be seen that the dotted lines, representing parallel rays meet nearer the lenses than those from the point A. The closer the object is to the lenses, the greater will be the divergence. This rule is applicable to copying, Did we wish to copy a 1/6 size daguerreotype on a 1/16 size plate, we would place it in such a position to the lenses at A, that the focus would be at F, where the image would be represented at about the proper size. Now, if we should wish to copy the 1/6 size picture, and produce another of exactly the same dimensions, we have only to bring it nearer to the lenses, so that the lens D E shall be equi- distant from the picture and the focus, i. e. from A to B. The reason of this is, that the distance of the picture from the lens, in the last copy, is less than the other, and the divergence has increased, throwing the focus further from the lens. These remarks have been introduced here as being important for those who may not understand the principles of enlarging or reducing pictures in copying. I would remark that the points F and A, in Fig. 9, are termed "conjugate foci." If we hold a double-convex lens opposite any object, we find that an inverted image of that object will be formed on a paper held behind it. To illustrate this more clearly, I will refer to the following wood-cut:— Fig. 10. "If A B C is an object placed before a convex lens, L L, every point of it will send forth rays in all directions; but, for the sake of simplicity, suppose only three points to give out rays, one at the top, one at the middle, and one at the bottom; the whole of the rays then that proceed from the point A, and fall on the lens L L, will be refracted and form an image somewhere on the line A G E, which is drawn direct through the centre of the lens; consequently the focus E, produced by the convergence of the rays proceeding from A, must form an image of A, only in a different relative position; the middle point of C, being in a direct line with the axis of the lens, will have its image formed on the axis F, and the rays proceeding from the point B will form an image at D; so that by imagining luminous objects to be made up of an infinite number of radiating points, and the rays from each individual point, although falling on the whole surface of the lens, to converge again and form a focus or representation of that point from which the rays first emerged, it will be very easy to comprehend how images are formed, and the cause of those images being reversed. "It must also be evident, that in the two triangles A G B and D G E, that E D, the length of the image, must be to A B, the length of the object, as G D, the distance of the image, is to G B, the distance of the object from the lens." It will be observed, that in the last cut the image produced by the lens is curved. Now, it would be impossible to produce a well-defined image from the centre to the edge upon a plain surface; the outer edges would be misty, indistinct, or crayon-like. The centre of the image might be represented clear and sharp on the ground glass, yet this would be far from the case in regard to the outer portions. This is called spherical aberration, and to it is due the want of distinctness which is frequently noticed around the edges of pictures taken in the camera. To secure a camera with a flat, sharp field, should be the object of every Operator; and, in a measure, this constitutes the great difference in cameras manufactured in this country. Spherical aberration is overcome by proper care in the formation of the lens:—"It can be shown upon mathematical data that a lens similar to that given in the following diagram—one surface of which is a section of an ellipse, and the other of a circle struck from the furthest of the two foci of that ellipse—produces no aberration. "At the earliest period of the employment of the camera obscura, a double-convex lens was used to produce the image; but this form was soon abandoned, on account of the spherical aberration so caused. Lenses for the photographic camera are now always ground of a concavo-convex form, or meniscus, which corresponds more nearly to the accompanying diagram." [-20-] [-21-] [-22-] [-23-] CHROMATIC ABERRATION. CAMERA TUBES AND LENSES. POSITION OF LENSES IN THE TUBE. Fig. 11. Chromatic Aberration is another difficulty that opticians have to contend with in the manufacturing of lenses. It will be remembered, that in a former page (14) a beam of light is decomposed by passing through a glass prism giving seven distinct colors—red, orange, yellow, green, blue, indigo and violet. Now, as has been said before, the dissimilar rays having an unequal degree of refrangibility, it will be impossible to obtain a focus by the light passing through a double-convex lens without its being fringed with color. Its effect will be readily understood by reference to the accompanying cut. Fig. 12. If L L be a double convex-lens, and R R R parallel rays of white light, composed of the seven colored rays, each having a different index of refraction, they cannot be refracted to one and the same point; the red rays, being the least refrangible, will be bent to r, and the violet rays, being the most refrangible, to v: the distance v r constitutes the chromatic aberration, and the circle, of which the diameter is a l, the place or point of mean refraction, and is called the circle of least aberration. If the rays of the sun are refracted by means of a lens, and the image received on a screen placed between C and o, so as to cut the cone L a l L, a luminous circle will be formed on the paper, only surrounded by a red border, because it is produced by a section of the cone L a l L, of which the external rays L a L l, are red; if the screen be moved to the other side of o, the luminous circle will be bordered with violet, because it will be a section of the cone M a M l, of which the exterior rays are violet. To avoid the influence of spherical aberration, and to render the phenomena of coloration more evident, let an opaque disc be placed over the central portion of the lens, so as to allow the rays only to pass which are at the edge of the glass; a violet image of the sun will then be seen at v, red at r, and, finally, images of all the colors of the spectrum in the intermediate space; consequently, the general image will not only be confused, but clothed with prismatic colors. To overcome the difficulty arising from the chromatic aberration, the optician has only to employ a combination of lenses of opposite focal length, and cut from glass possessing different refrangible powers, so that the rays of light passing through the one are strongly refracted, and in the other are bent asunder again, reproducing white light. To the photographer one of the most important features, requiring his particular attention, is, that he be provided with a good lens. By the remarks given in the preceding pages, he will be enabled, in a measure, to judge of some of the difficulties to which he is occasionally subjected. We have in this country but two or three individuals who are giving their attention to the manufacture of lenses, and their construction is such, that they are quite free from the spherical or chromatic aberration. CHAPTER II. CAMERA—ARRANGEMENT OF LENSES—CAMERA TUBES—CAMERA-BOXES, BELLOWS, AND COPYING—CAMERA STANDS—HEAD RESTS—CLEANING VICE—NITRATE BATH—LEVELING STANDS—PRINTING FRAMES—COLLODION VIALS. Babtista Porta, when he saw for the first time, on the walls of his dark chamber, the images of external nature, pictured by a sunbeam which found its way through only a small hole, little thought of the importance which would be attached to the instrument he was, from this cause, led to invent. The camera obscura of this Italian philosopher remained as a mere scientific toy for years, and it was not until Daguerre's discovery that its true value was estimated. It now plays a very important part in giving employment to at least ten thousand persons in this country alone. It is of the utmost importance, in selecting a set of apparatus, to secure a good camera; for without such no one can obtain fine pictures. In testing it, see that it gives the pupil of the eye and lineaments of the features sharp and distinct; and that the whole image on the ground glass has a fine pearly hue. Look also to the field, and observe that the focus is good at the centre and extreme edges of the ground glass, at the same time. A poor camera generally gives a misty image, with the lights and shades apparently running together. The best American cameras are fully equal to those imported, while they cost much less; but there are great numbers sold which are not worth using. If a lens gives a well defined image on the ground glass, it should do the same on the plate. Many a valuable lens has been condemned for failing in this, merely in consequence of the plate-holder not being in focus with the ground-glass. In case of deficiency in this, put a glass into the holder, lay a rule across the face, and measure the distance between them very exactly; measure the ground-glass in the same way, and make the distance agree perfectly, by moving the ground-glass either back or forward in the frame, as the case may be, so that the surface of the glass plate shall occupy precisely the same position as the face of the ground-glass when in the camera. Fig. 13. Fig. 14. It is very desirable that the operator should understand the arrangement of the lenses in the tube; it not unfrequently happens, that in taking out the "glasses" to clean them, he does not return them to their proper places, and the result is that his "camera is spoiled." A couple of illustrations and a few remarks will be sufficient to enable any one to replace the lenses in them properly. Fig. 13 represents the tube for holding the lens, and Fig. 14 shows their arrangement. It will be seen that the two back lenses have a small space between them; this separation is kept by a small tube or ring of the same circumference as the lens. The two front lenses are nearest together. It will be observed that the two thick lenses are towards each other; these are made of flint glass containing much oxide of lead. The other two are double convex, and are made of crown glass. By noting the fact that the two cemented lenses go in the front of the tube, the glass having the thickest edge goes inside, and that the thickest lens of the other two goes in first, from the back of the tube, it will not be easy for the operator to make a mistake in returning the "glasses." "I will remark that a diaphragm diminishes both chromatic and spherical aberration, by cutting off the outside portion of the lens. It lessens the brilliancy of the image, but improves the distinctness by preventing various rays from interfering with and confusing each other; it also causes a variety of objects at different distances to be in focus at the same time." [-24-] [-25-] [-26-] [-27-] [-28-] CAMERA BOXES. Fig. 15. The tube containing the lenses is to be mounted on a box (camera-box) as in Fig. 15. For this purpose there are several patterns of boxes, from among which I have made two selections of the most approved, and represent them by cuts, Figs. 16, 17, 18. Fig. 16. Fig. 17. Figs. 16 and 17 represent a bellows-box which is probably more in use than all the other patterns together. They serve both for copying and taking portraits from life. A is the base; B is the back and sliding-box; C, bellows, which admits of extension or contraction; D is the opening to receive the carriage A, Fig. 17; E is a thumb screw to hold the sliding-box at any required distance. Fig. 17 represents the plate-holder and ground glass frame. A, carriage to pass through D, Fig. 16; B, frame for ground-glass, which may be turned in a horizontal or perpendicular position; C, a movable plate-holder held in place by means of springs; D, reducing holder, with bottom and plate to hold the glass plate: any size of reducing frame can be put in frame C; E E, spring bottom to keep frame D in place; F, slide; G, thumb-screw, when the carriage is to be put in or taken out of the box, Fig 16; H H, spring bottom to hold B in place. Bellows-boxes can be obtained which receive the plate-holder from the top, the same as in the copying-box, Figs. 15 and 18. The common wood, or "copying-box," is represented by Fig. 18. Fig 18. A, being the main or outside box, is made of wood veneered with rosewood; B is another box which fits into A, sliding in and out as required. The ground glass and plate-holders fit grooves made in the inside box. In regard to plate-holders or tablets for holding the glass plates, it need only be said that the camera-boxes are accompanied with a complete set, so arranged that the light is wholly excluded from the plate while drawing out or pushing in the slide, for shutting off the light while the holder is out of the box. Should any one be desirous of using the same camera, for taking both glass and daguerreotype pictures, it will be necessary for him to be provided with two sets of tablets for his box, one for each process. Fig. 19. [-29-] [-30-] [-31-] CAMERA STANDS, ARM STANDS. HEAD RESTS. PLATE-HOLDERS, BATH, DIPPING RODS. Camera Stands. There are several patterns of these; almost every dealer has some particular style, which, if not for beauty, for his interest, suits his purposes best. Among the assortment, I will present only two illustrations. The first, Fig. 19, represents one which has an advantage over many others; it is made of cast iron, and of an ornamental pattern:—A, base on castors; B, fluted hollow column, which admits the iron tube C, which has on one side a hollow tooth rack to receive a spiral thread on the inner face of wheel D; this wheel, when turned, elevates or lowers the tube C to any desired height; E, thumb wheel attached to a screw which sets against tube C, to hold it in position, F, a pinion by which the camera can be directed; G G, thumb screws to hold the two plates together when in position. It is quite heavy, stands firm and solid, and is not liable to be moved by the jar from walking over the floor. For permanently located operators these are the most desirable; but for those who are moving about from place to place, and those who wish to take views, a lighter article would be more convenient, such as one represented at Fig. 20. This stand is made principally of wood, and can be readily taken apart, so as to be packed in an ordinary sized trunk. Fig. 20. Fig. 21. Fig. 21 represents a small "Jenny Lind Stand," and is a very convenient article for the sitter to lean a hand or arm upon while sitting for a portrait; It is fixed with a rod for raising or lowering the top, and can be adjusted to any required height. Head Rests. There are several patterns of head supports, or, as they are commonly called, head rests, in use by the profession. I give two illustrations (Figs. 22 and 23). The first is an independent iron rest, known as the "Jenny Lind Rest;" and the other is for fastening to the back of a chair, as seen in the cut. For general use, I would recommend the iron independent rest as far more advisable than any other. Fig. 22. Fig. 23. Vices for Holding Glass. The article used for holding the glass, during the process of cleaning, is called a vice; and, of the numerous styles recently introduced, I find none that I would prefer to the old one known in market as "Peck's Vice;" it is simple and easy in operation, and at the same time is effectual. Fig. 24 represents this vice, which is to be firmly secured to a bench; the small piece of wood attached to the bottom is of no use. A A are the grooved for receiving the daguerreotype plate-block; but as they are too deep for the glass, I pin on a small strip of wood, so that the upper edge of the glass will be a little above the projection of the vice. Fig. 24. [-32-] [-33-] [-34-] LEVELING STANDS. PRINTING FRAMES. Fig. 25. Fig. 26. Fig. 27. Nitrate Baths and Dipping Rods. The accompanying illustration, Fig. 25, a, represents a bath for holding the nitrate of silver solution. This shape is of my own suggestion, and the best adapted to the wants of the photographer. It will be seen that the front side is rounding, with a curve extending from side to side. By this shape, the face of the glass is protected from coming in contact with the side of the bath—both edges of it turning so as to prevent injury. There is a small projection on the top, at the opposite side of the oval; this is to allow the solution to flow over and wash off any dust that may have gathered upon the surface of the solution. This wash runs out of a small tube, as is shown in the cut. Any convenient vessel can be placed under it to receive the liquid. This can be filtered and returned as often as required. I am not in the practice of filling my baths full of solution, but always keep them filtered and clean; hence saving an excess of solution. b represents a little support, which is secured at its base Upon the shelf, to hold the bath in a slightly inclined position, which is preferable to having it stand perpendicularly. Fig. 28. Fig. 29. Fig. 30. Leveling Stands. Persons oftentimes require a rest or place to put their glass during development or washing the picture. Either of the stands represented by the annexed cut will answer the purpose. Fig. 30 is known to the daguerreotype operator as a "gilding stand," and is the one best adapted to the wants of operators on glass. It may be so arranged as to give the surface of the glass a water-level; D D are thumb-screws, by means of which, when properly regulated, the frame G may hold glass perfectly level and a large quantity of solution may be poured over the surface. Printing Frames. There are numerous methods and apparatus used for holding the negative and the paper during exposure to the light. The following illustrations represent a convenient and economical frame for this purpose. Fig. 31. Fig. 32. Fig. 31 represents the front of the frame. The negative glass is held upon it by springs attached by screws to the bottom half of the frame, A, so that they can be turned on or off, to suit the different sizes of glass. On the other end of the spring are wooden buttons, which are placed on the edges of the glass negative, holding it in its place, and pressing it firmly against the paper which is placed under it. This frame is made of two pieces of inch board, which are connected by hinges, falling over as seen in Fig. 32, B being the half that is movable. This movable half is secured in position by means of a wooden button, attached to A on the back and under B, as seen in Fig. 32. The separate pieces, A and B, are bevelled where they connect, as seen by Fig. 31. D (in Fig. 32) is one of the springs, which can be seen in Fig. 31. The entire bed or face of the frame, A and B, should be covered with a thick piece of satinet cloth, which may be pasted to the lower half, A, and extended over the entire surface of A and B. This forms a pad for the paper. This printing frame can be easily made by any cabinet-maker or carpenter. The springs may be of sheet iron or brass—either will be found sufficiently stiff for the purpose. Every operator should be provided with from four to ten frames: the saving of time will be found to amply repay the expenditure necessary for a good supply. Fig. 33. Another article called a pressure frame, is represented in the accompanying figure. This is more expensive than the first, and is by some considered preferable. Another cheap, convenient and equally good arrangement for holding the negative and paper, is to take three glasses—say one a full size, being the one having the negative upon it; and then take two glasses, each just half the size of the negative, and have a piece of very thick heavy cloth cut the size of the negative glass, [-35-] [-36-] [-37-] [-38-] COLLODION VIALS. COLOR-BOXES. which can be put between it and the two half glasses, and then they can be held together by means of the common spring clothes pin. The advantage of the two glasses at the back is, that one can be entirely removed while the picture is being examined, and afterwards returned without, in the least, moving the impression. Collodion Vial.—Color-Boxes. This shaped vial is made expressly for collodion, to which purpose it is admirably adapted. It has a wide mouth, and is so constructed that the liquid flows clear and free. It is deep, and with a heavy protruding base, to prevent its falling. There are two sizes made at present, one to contain 2½ ounces—the other, 1½ ounce. I generally use the smaller ones, but always keep on hand, and would not be without, a few of the larger size. Fig. 34. Fig. 35. Fig. 35 represents a color-box. These can be had of any dealer, completely fitted, with color and brushes for use. CHEMISTRY. PRACTICAL HINTS ON PHOTOGRAPHIC CHEMISTRY. CHAPTER III. SOLUBLE COTTON—MANIPULATION—PLAIN COLLODION—BROMO-IODIZED COLLODION FOR POSITIVES—DITTO FOR NEGATIVES —SOLUTION OF BROMIDE AND IODIDE OF POTASSIUM AND SILVER—DOUBLE IODIDE OF POTASSIUM AND SILVER— DEVELOPING SOLUTION—FIXING THE SOLUTION—BRIGHTENING AND FINISHING THE IMAGE—PHOTOGRAPHIC CHEMICALS. The chemistry of Photography requires the attention, in a greater or less degree, of every practitioner. It is of the utmost importance, that those who wish to meet with success in the various processes given, should not only be provided with a good selection of chemicals, but also understand the nature of the agent employed. To give a perfectly complete and full list of every agent used would require more time and space than can be given in this work. I shall confine myself to some of the most important, and to such articles as are of the greatest interest to the practitioner. Soluble Cotton. I have, in my practice and trade, adopted the term soluble cotton as the one most appropriate, making a desirable distinction from the article sold as gun cotton, they being of a somewhat different nature—gun cotton being the most explosive and least soluble, while the other preparation is more soluble and less explosive. There are two methods employed in the preparation of soluble cotton; one being by the use of nitric and sulphuric acids, and the other with sulphuric acid and nitrate of potash. The last of these I would recommend as being the most convenient for those who require only a small quantity of cotton. Persons experimenting in the preparation of this article should exercise much care and judgment. A good cotton is not the result of hap-hazard operation. The operator should be acquainted, as nearly as possible, with the quality of the chemicals employed, and the proper mode of manipulation. Articles necessary.—One quart Wedgewood mortar and pestle, or evaporating dish; one glass rod; one pane of glass, large enough to cover the mortar or dish; one ordinary-sized pail two-thirds full of pure rain or distilled water, and at least ten times that quantity of water at hand; twelve ounces (by weight, avoirdupois) of nitrate of potash (Dupont's refined, pulverized); twelve ounces (by measure) of commercial sulphuric acid; and three hundred and forty grains of clean, pure cotton wool. Remarks.—It is advisable that the mortar or dish be deep and narrow, as the mixture can be better formed in a vessel of this shape. If not convenient to procure a mortar, a common earthen bowl will answer; glass is objectionable, as the heat generated in the combination of the acid and nitre is liable to crack it. A new pail should not be used, especially if it is painted, as the acids attack the paint, and injure the cotton. I prefer one that has been used for some time, and has been frequently cleaned. A common earthen wash-bowl, or any large glass dish, will answer in place of the pail. Metal pails or vessels should not be used. Nitrate of Potash (saltpetre) should be dry and finely-powdered. I use none other than Dupont's refined; this is very nearly, if not absolutely, chemically pure. The commercial Sulphuric Acid (oil of vitriol) of America is of great uniformity of strength, as sold by druggists generally. I use a test-bulb graduated to the proper density, and have been very successful in my experiments. In some twenty different samples of acid, used in different cities in the United States, I found only one that produced a poor cotton, and this might have been influenced by the moisture of the atmosphere, it being a very rainy day when I used it. During my recent and somewhat extensive practice, I have thought that the fine long fibres of cotton wool do not make so desirable a soluble cotton as that which is heavy or common. Four or five very careful experiments upon this point, have had the effect to produce in me a strong belief that my ideas are entitled to some consideration. I should not select the finest cotton for making soluble cotton, but now invariably take that which is thick or coarse. The result of my experience is (other things being equal), that cotton prepared in fine dry weather has a greater degree of solubility than when prepared in a moist atmosphere: hence I would recommend the experimenter to choose fine, clear weather for preparing it. Manipulation. Having at hand every article requisite, proceed as follows:—Put the nitrate of potash into the mortar or dish; be sure it is dry and well powdered, and then add the acid; stir them well with the pestle and glass rod, so that the lumps will be all (or nearly so) out, and a pasty solution formed. This operation should not occupy more than two minutes' time. Then put in the cotton, about one-quarter of the whole bulk at a time: it should be well picked apart, so that it may come immediately [-39-] [-40-] [-41-] [-42-] [-43-] [-44-] in contact with the acids, and should be kneaded, with the pestle and glass rod, into the solution, and as soon as wetted, another quarter should be added and wetted as soon as possible; so continue until all is in: then knead with the pestle and mortar for at least four minutes, or until every fibre of the cotton is saturated with the liquid; then the mortar should be covered over with the pane of glass, and allowed to stand for fifteen or twenty minutes; then the entire contents of the mortar should be thrown into the pail two-thirds full of water, and stirred with the glass rod as rapidly as possible: if this rapid stirring is omitted, the cotton will be injured by the action of the acids in combining with the water. The water should be poured off, and another change put into the pail. After about three changes, the hands may be used in the farther washing. The hands should be perfectly clean, and free from all chemicals. The changes of water and washing should be continued until every trace of acid has disappeared, which can be seen by testing with blue litmus test-paper. After it is thought that the cotton has become free, the water may be squeezed out of a little lump about the size of a pea, and then placed between the fold of the test-paper, and if it reddens the paper, there is acid present, and the washing should be continued until there is no change in the paper. When this is done, the cotton can be put into the folds of a dry towel or cloth (which has been thoroughly rinsed, so that no soap be present), and wrung out as dry as possible, and then it may be picked apart and put aside, exposed to a moderate temperature (say 100° Fahr.) to dry, when it is ready for use. I employ the method (for convenience, nothing more) of displacing the water by the use of alcohol. [Cutting's patent—see patents.] I wring out the water as before, then place the cotton in strong alcohol, stir and press it, and then pour it off; wring it out again, then put it in a change of alcohol, let it soak for about five minutes, then wring it out as dry as possible, pick it apart, and it will dry immediately, and place it in a close stoppered bottle; or, if wanted for use at once, put it into the dissolving solution immediately. I will here remark that, since the first edition, I have had occasion to use large quantities of soluble cotton, and have found that if it be kept in an atmosphere of alcohol and ether, its solubility is somewhat improved: that is, in the case of its not being used immediately after its preparation. This is easily kept, by dropping a few drops of ether or alcohol into the bottle containing it, and then sealing close until wanted for use. In the event of the water being displaced by alcohol, it is not necessary to thoroughly dry it, but put in a perfectly close bottle to keep. Remarks.—There are a...