take a piece of this paper of the proper size, and lay it on the varnished or pictured side of the negative, which is itself laid in a wooden frame, like a picture-frame. Then we place a thick piece of cloth on the paper. Then we lay a hinged wooden back on the cloth, and by means of two brass springs press all close together,—the wooden back against the cloth, the cloth against the paper, the paper against the negative. We turn the frame over and see that the plain side of the glass negative is clean. And now we step out upon the roof of the house into the bright sunshine, and lay the frame, with the glass uppermost, in the full blaze of light. For a very little while we can see the paper darkening through the negative, but presently it clouds so much that its further changes cannot be recognized. When we think it has darkened nearly enough, we turn it over, open a part of the hinged back, turn down first a portion of the thick cloth, and then enough of the paper to see something of the forming picture. If not printed dark enough as yet, we turn back to their places successively the picture, the cloth, the opened part of the frame, and lay it again in the sun. It is just like cooking: the sun is the fire, and the picture is the cake; when it is browned exactly to the right point, we take it off the fire. A photograph-printer will have fifty or more pictures printing at once, and he keeps going up and down the line, opening the frames to look and see how they are getting on. As fast as they are done, he turns them over, back to the sun, and the cooking process stops at once.
The pictures which have just been printed in the sunshine are of a peculiar purple tint, and still sensitive to the light, which will first "flatten them out," and finally darken the whole paper, if they are exposed to it before the series of processes which "fixes" and "tones" them. They are kept shady, therefore, until a batch is ready to go down to the toning room.
When they reach that part of the establishment, the first thing that is done with them is to throw them face down upon the surface of a salt bath. Their purple changes at once to a dull red. They are then washed in clean water for a few minutes, and after that laid, face up, in a solution of chloride of gold with a salt of soda. Here they must lie for some minutes at least; for the change, which we can watch by the scanty daylight admitted, goes on slowly. Gradually they turn to a darker shade; the reddish tint becomes lilac, purple, brown, of somewhat different tints in different cases. When the process seems to have gone far enough, the picture is thrown into a bath containing hyposulphite of soda, which dissolves the superfluous, unstable compounds, and rapidly clears up the lighter portions of the picture. On being removed from this, it is thoroughly washed, dried, and mounted, by pasting it with starch or dextrine to a card of the proper size.
The reader who has followed the details of the process may like to know what are the common difficulties the beginner meets with.
The first is in coating the glass with collodion. It takes some practice to learn to do this neatly and uniformly.
The second is in timing the immersion in the nitrate-of-silver bath. This is easily overcome; the glass may be examined by the feeble lamp-light at the end of two or three minutes, and if the surface looks streaky, replunged in the bath for a minute or two more, or until the surface looks smooth.
The third is in getting an exact focus in the camera, which wants good eyes, or strong glasses for poor ones.
The fourth is in timing the exposure. This is the most delicate of all the processes. Experience alone can teach the time required with different objects in different lights. Here are four card-portraits from a negative taken from one of Barry's crayon-pictures, illustrating an experiment which will prove very useful to the beginner. The negative of No. 1 was exposed only two seconds. The young lady's face is very dusky on a very dusky ground. The lights have hardly come out at all. No. 2 was exposed five seconds. Undertimed, but much cleared up. No. 3 was exposed fifteen seconds, about the proper time. It is the best of the series, but the negative ought to have been intensified. It looks as if Miss E.V. had washed her face since the five-seconds picture was taken. No. 4 was exposed sixty seconds, that is to say, three or four times too long. It has a curious resemblance to No. 1, but is less dusky. The contrasts of light and shade which gave life to No. 3 have disappeared, and the face looks as if a second application of soap would improve it. A few trials of this kind will teach the eye to recognize the appearances of under- and over-exposure, so that, if the first negative proves to have been too long or too short a time in the camera, the proper period of exposure for the next may be pretty easily determined.
The printing from the negative is less difficult, because we can examine the picture as often as we choose; but it may be well to undertime and overtime some pictures, for the sake of a lesson like that taught by the series of pictures from the four negatives.
The only other point likely to prove difficult is the toning in the gold bath. As the picture can be watched, however, a very little practice will enable us to recognize the shade which indicates that this part of the process is finished.
We have copied a picture, but we can take a portrait from Nature just as easily, except for a little more trouble in adjusting the position and managing the light. So easy is it to reproduce the faces that we love to look upon; so simple is that marvellous work by which we preserve the first smile of infancy and the last look of age: the most precious gift Art ever bestowed upon love and friendship!
It will be observed that the glass plate, covered with its film of collodion, was removed directly from the nitrate-of-silver bath to the camera, so as to be exposed to its image while still wet. It is obvious that this process is one that can hardly be performed conveniently at a distance from the artist's place of work. Solutions of nitrate of silver are not carried about and decanted into baths and back again into bottles without tracking their path on persons and things. The photophobia of the "sensitized" plate, of course, requires a dark apartment of some kind: commonly a folding tent is made to answer the purpose in photographic excursions. It becomes, therefore, a serious matter to transport all that is required to make a negative according to the method described. It has consequently been a great desideratum to find some way of preparing a sensitive plate which could be dried and laid away, retaining its sensitive quality for days or weeks until wanted. The artist would then have to take with him nothing but his camera and his dry sensitive plates. After exposing these in the camera, they would be kept in dark boxes until he was ready to develop them at leisure on returning to his atelier.
Many "dry methods" have been contrived, of which the tannin process is in most favor. The plate, after being "sensitized" and washed, is plunged in a bath containing ten grains of tannin to an ounce of water. It is then dried, and may be kept for a long time without losing its sensitive quality. It is placed dry in the camera, and developed by wetting it and then pouring over it a mixture of pyrogallic acid and the solution of nitrate of silver. Amateurs find this the best way for taking scenery, and produce admirable pictures by it, as we shall mention by-and-by.
In our former articles we have spoken principally of stereoscopic pictures. These are still our chief favorites for scenery, for architectural objects, for almost everything but portraits,—and even these last acquire a reality in the stereoscope which they can get in no other way. In this third photographic excursion we must only touch briefly upon the stereograph. Yet we have something to add to what we said before on this topic.
One of the most interesting accessions to our collection is a series of twelve views, on glass, of scenes and objects in California, sent us with unprovoked liberality by the artist, Mr. Watkins. As specimens of art they are admirable, and some of the subjects are among the most interesting to be found in the whole realm of Nature. Thus, the great tree, the "Grizzly Giant," of Mariposa, is shown in two admirable views; the mighty precipice of El Capitan, more than three thousand feet in precipitous height,—the three conical hill-tops of Yo Semite, taken, not as they soar into the atmosphere, but as they are reflected in the calm waters below,—these and others are shown, clear, yet soft, vigorous in the foreground, delicately distinct in the distance, in a perfection of art which compares with the finest European work.
The "London Stereoscopic Company" has produced some very beautiful paper
