Towler, John. The Silver Sunbeam. Joseph H. Ladd, New York: 1864. Electronic edition prepared from facsimile edition of Morgan and Morgan, Inc., Hastings-on-Hudson, New York. Second printing, Feb. 1974. ISBN 871000-005-9

Chapter III.
SPECIALTIES IN REFERENCE TO THE ARTICLES IN THE PRECEDING CHAPTER-THE GLASS-HOUSE, ETC.

THE first thing which claims the attention of the photographer, is to secure to himself suitable rooms. In many instances the artist has the privilege of superintending the construction of his glass-house or operating-rooms; in this case he must not only know what is required in such a construction, but he must know what arrangements are the most appropriate. The success of many an artist depends upon the fortuitous advantages of his glass-house; but these fortuitous advantages depend upon fixed laws and principles which the photographer must learn, if he is still ignorant of them. To be brief, contrast between light and shade is agreeable to the eye, whether tutored or untutored; whereas uniformity of light or of shade is very displeasing. It is not known why this is so any more than why harmonious combinations of notes are delightful to the ear, or why noncoincident vibrations produce discord. By means of a happily arranged contrast of light and shade, a stereographic roundness is communicated to pictures which, where this contrast is deficient or quite wanting, are flat and in no way satisfactory; and where the contrast is exaggerated-where the lights are very bright and the shades very deep-where the transition from one to the other is direct, and the line of demarcation between them is almost visible-the roundness becomes a complete distortion of solidity. This distortion, arising from a vulgar contrast, is sometimes so great as to cause the sitter to disclaim his own picture. The qualifications of an artist are very distinct from those of a mere operator; the former, by reason of his qualifications, can associate with gentlemen and the intelligent; the latter can aspire to no higher companionship than with the ignorant and vulgar. But the qualifications in question are attributable, in a great measure, to a thorough knowledge of light in reference to his art, whereby nature becomes natural.

If an object be placed so that the light in one direction, whether brilliant or dull, falls perpendicularly upon its surface, the picture will be flat and disagreeable, because there is no contrast; if the light falls obliquely, the contrast will be displeasing according to its intensity, because the shadows will be elongated and distinctly marked from the lights. A single light, therefore, can scarcely be said to produce an artistic satisfaction.

Two equally bright lights, in opposite directions, or rather in directions at right angles to each other, are very objectionable, because either produces a bright circle of light in the eyes, which is repugnant to an artist's feelings, from the fact that the picture is severely flat for want of contrast.

If lights proceed from two directions, at right angles to each other, or somewhere in the neighborhood of this angle, of which one is more brilliant than the other, then it is possible so to arrange the sitter or model as to satisfy a cultivated taste.

The greater the brilliancy of the light, the more unmanageable it becomes in the production of that soft merging of light into shade which in photography is so much required. It is, therefore, quite objectionable to use the direct rays of the sun in taking portraits. But during the day these rays proceed from three directions of the compass-in the morning from the east, at noon from the south, and in the evening from the west; from the north alone, in the northern hemisphere, the rays never emerge. But the northern sky or space is illumined by the direct light from the sun, which, by reflection and diffusion, has parted with much of its offensive brilliancy, and is rendered soft and manageable. The direct light into the glass-house, therefore, must enter from the north; this is the light which performs, or is to perform, the principal part in the production of a negative. Now this single light, which enters from the northern part of the hemisphere, or a portion of it at least, may be softened down by reflection from side-screens, and so directed by them upon the sitter as to make any degree of agreeable contrast. With these principles in view, the glass-house must be constructed. If the operating-room is situated in the highest story of a house, this house ought to be at least as high as the adjoining or contiguous buildings; and the glass window on the roof must be quite unobstructed by chimneys or trees in a direction perpendicular to its surface.

Supposing the ends of the building in which it is required to construct a photographic establishment face east and west, the following arrangement is one which I would recommend

Let the southern side-wall be raised until it is as high as the ridge of the roof; in like manner fill up to the same height the triangular space in the end-wall between the chimney and the southern wall now raised, either on the eastern or western end, as it may happen to be; at a distance of fifteen feet from the end-wall raise another, equally high, and parallel with it, from the southern side to the ridge of the roof. Next construct a water-tight flat roof; beginning at the side and running toward the north about ten feet. Where this terminates, introduce the wooden frame, the southern portion inclining to the horizon toward the north at an angle of forty-five degrees, to contain the sky-light, which may be fifteen feet wide by twelve feet deep, and inclined at an angle of forty-five degrees with the horizon and facing the north; the southern part of the frame and the window, therefore, comprehend a right angle. Where it is practicable, it is well to have a window in either of the end-walls, furnished with sets of tight shutters about four feet wide, and proceeding (in direct contact, at the commencement, with the part of the sky-light nearest the north) downward to within two feet from the floor. Such side-lights can frequently be used instead of screens; and by the adjustment of the shutters, light can be admitted as required, either as regards quantity or direction, that is, from the west in the morning, and from the east in the evening. From the lowest part of the skylight downward, and right across the room, the space is boarded Lip about four feet deep, and then the remaining part overhead is a flat ceiling as far as the northern side of the building. The length of this room must be about thirty feet. The dark-chamber and the ordinary work-room may be constructed on the northern side, the window of one being glazed with an orange-yellow colored glass, in order to absorb the actinic rays, and the other with common crown-glass. On the outside of the side-windows, small platforms are formed for the reception of the printing-frames, where no other room can be had separately and especially for the direct-printing department. The sky-light and the sidelights have to be furnished with curtains, in order to soften or modify the light, which has access according to the circumstances of the case or the taste of the artist. The backgrounds are placed in the space beneath the flat roof; oil the southern side, and so far back as to cut off, as much as possible, the direct rays upon the head of the sitter. The northern end must be papered with a grayish-colored paper--the more uniform the better-so as to keep this part as feebly lighted as possible. It is even advisable to have the part where the camera is situated entirely curtained off from the remaining space; by such an arrangement, the operator requires no focussing-cloth, and the curtains being of some material such its wool, and of a deadened color, the sitter's eyes are never strained by looking in this direction.

It happens, however, very frequently, that photographers can not direct the construction of their rooms, and that the sky-light is inserted directly into the slanting side of the roof. In this case, if the light comes from the north, the room will have a direction from east to west, the sitter being placed at either end, according to circumstances. Here only one side-light can be used; to compensate the want of a southern side-light, a screen, movable on an axis, is placed in its stead, which, receiving light either from above or the opposite side, can be made to reflect the same in the direction required.

Where the ridge of the roof of a building is directly north and South, and a sky-light has to be constructed on the slanting roof, there seems to be no alternative but to make two skylights, one on either side, furnished with thick curtains within, and on the outside with a tall partition between them, as also one on the southern side, to exclude the direct rays of the sun;. or to construct a suite of rooms, by raising one of the side-walls of the building as nearly in accordance with the plan first proposed, with those exceptions only which the nature of the building would demand. For instance, if the building were somewhat wide, there would be only one side-window, and the facilities for printing would not be so great, unless some room could be fixed up with a southern aspect. The illumination of the background by the light from the sky-light, just described, is uniform, because the construction of the frame admits an equal quantity at the top as well as at the bottom. The ordinary mode of erecting the southern part of the frame, which supports the sky-light in a position perpendicular to the horizon, excludes much of the light, and forms a shadow on the upper part of the background, unless a contrivance of reflection overhead causes the illumination to be equally and uniformly distributed.

The screens or backgrounds for placing behind the model are various. If the background is to be quite white, the screen must be white; if intermediate between black and white, the screen may be gray, grayish-blue, blue, and violet. A red. orange-red, yellow, and black screen will produce a dark-colored background, from the fact that light, impinging upon such surfaces, reflects scarcely any but three colors, and absorbs almost all the rest; but these colors are known by experience to be possessed of little or no actinic influence. Screens with graduated tints, shading off from one color into another, or gradually shading off from a deep to a light color, are to be highly recommended to an artistic operator. Other screens again represent landscapes, castles, shipping, city scenery, etc., in dark-colored outlines and shading, on a gray or bluish-gray foundation. Such representations are very pleasing to the uneducated taste; the true artist sometimes seems to regard them as finical. If such backgrounds are in true perspective, are correct representations of natural objects and scenery, and can be well focussed on the ground-glass, I would not hesitate to pronounce them legitimately artistic, and as such they must enhance the value of a card-picture or other photograph. On the contrary, if the productions are rude, faulty, and carelessly shaded, their images on the collodion-film will be equally so, and even more so, by distortion from the lenses, and will tend to communicate to the photograph a vulgar appearance.

On the subject of light, a few words more will suffice in this section. Place the model in a very easy and graceful manner, either standing or sitting, leaning on a pillar, balustrade, or small stand, in such a manner that every part is nearly equally in focus, but especially the hands, face, and feet, (if the latter are to be visible.) Avoid as much as possible that silly clinging to uniformity in the position of the sitter, which some operators fall into, as of laying the hands folded together on the lap, or of fixing the thumb in the armhole of the vest. Such sameness becomes a characteristic of the gallery, and renders the specimens that proceed from it ridiculous. Old and young, handsome and ugly, the grieved and the joyous, have all been invested in the same exuviae, have all been grouped or posed amid the same accoutrements. Above all things, endeavor at least to produce a variety of position and paraphernalia in the respective members of one and the same family; otherwise, your photographs will be no better than the painting of Dr. Goldsmith's family in the Vicar of Wakefield, in which is beheld an orange in the hand of each figure. As soon as the figure or group is fixed in a pleasing, an easy, and artistic position, the next and a very important business presents itself, which consists in illuminating this figure or group in such a way as to obtain a clear and distinct image on the ground-glass of the camera. If the light falls too much on the head, prevent this by means of the curtain on the skylight; if the shadows are too strong, and apparent beneath the eyebrows, nose, or chin, correct this defect by means of the side-light or the movable screen, recollecting the first law of reflection of light, which teaches that the angle of incidence is equal to the angle of reflection, so that, if the screen be inclined to the horizon at an angle of forty-five degrees, rays that fall upon it through the slay-light will pass off from it in a direction parallel with the horizon, and in a good condition for destroying those horrid black specks of shadow wherever there exist prominences or cavities. The great art in photography is to simplify the light to the very utmost, to use if possible light from two directions alone, and only that sort of light which is endowed with actinic influence on the sensitized plates. It will frequently happen that, with the most brilliant illumination, no other but a hazy image of the model can be obtained on the ground-glass; and where this image is thus indistinct and fuzzy on the ground-glass, it is utterly impossible to obtain any better result on the film of collodion. The haziness in question is caused by a multiplicity of reflections of light, by which rays interfere, cross each other, and are jumbled together in a very irregular and heterogeneous manner, and also by the impure and unequally dense layers of air and vapor set in motion in the room, which produce an atmosphere in front of and around the sitter similar to those dazzling ascending columns of air visible at the sides and on the top of a stove. To avoid the first cause, it is recommended to glaze the skylight with glass containing cobalt, which communicates to it a blue or violet tinge. Such glass excludes all superfluous light, allows only actinic rays to penetrate, and subdues the illumination to such a degree as to render the image on the ground-glass quite distinct and agreeable to the eye. Although the room, by such glazing, is considerably darkened, the operations in photography are incomparably superior in result, and the time of exposure is not lengthened. The second cause is obviated by preserving a uniform temperature in the room, and by having the currents of ventilation proceeding to their exit at some distance from the sitter. Let me finally impress upon every photographer the absolute necessity he is placed in of learning to manage the light, before he can ever hope to be successful in the subsequent operations with chemical materials. An imperfectly lighted picture can never be metamorphosed afterward into a respectable production.