[D] One of the most desirable articles I have found for this purpose is the wide (3 inch) flat camel's-hair brush often called a blender.
Fig. A. Fig. B.
The glass is held between the thumb and forefinger of the left hand by the corner 1, Fig. A., 3 and 4 towards and nearest the body, and as nearly level as possible. I find this the best position to hold the glass; as, in the case of the larger ones, they can be rested on the end of the little finger, which should be placed as near the edge as possible. Then, from the collodion vial, pour on the collodion, commencing a little beyond the centre and towards 1, continuing pouring in the same place until the collodion nearly reaches the thumb—the glass slightly inclined that way; then let the glass incline towards 4, and continue to pour towards 2.
As soon as enough has been put on to liberally flow the glass, rapidly and steadily raise corner 1, and hold it directly over 3, where the excess will flow oil into the mouth of the vial, which should be placed there to receive it. In case of a speck of dust falling at the time of coating, it can often be prevented from injuring the surface by changing the direction of the flowing collodion, so as to stop it in some place where it will not be seen when the picture is finished. Now, with the thumb and finger of the right hand, I wipe off any drops or lines of collodion that may be found upon the outer edge or side of the glass, being careful not to disturb that connected with the face.
When the coating has become sufficiently dry, so that when I put my finger against it, it does not break the film, but only leaves a print, I put it into the silvering bath [see Fig. p. 34]. I generally try corners 2 and 3. The time, from the first commencement of pouring on collodion to its being put into the bath, should not exceed about half a minute, at a temperature of 60°. The finger test is the best I have found. The glass is to be rested on a dipper [see Fig. p. 34], and placed steadily and firmly into the nitrate of silver bath—this in a dark room. It should not be allowed to rest for an instant as it is entering the solution, or it would cause a line. The time for the glass to remain in the bath depends upon the age and amount of silver the bath contains; for a new solution, from two to three minutes will be sufficient to give the proper action. If it be old, three to five minutes will be better. When it is properly coated, it can be raised up and taken by the corner, and allowed to drain for a few seconds, and then should be placed in the tablet, and is ready for the camera. The time of exposure will depend upon the amount of light present. If the bath is newly mixed, and the collodion recently iodized, it should produce a sufficiently strong impression by an exposure of about one-third of the time required for a daguerreotype. If the collodion has been iodized some time, and the bath is old, about one-half of the time necessary to produce a daguerreian image will be required.
The plate should in no case be allowed to become dry from the time it is taken from the bath up to the time of pouring on the developer. At a temperature of about 70°, I have had the glass out of the bath ten minutes without drying. After exposure, the glass should be taken again into the dark room, and removed from the tablet and held over a sink, pail, or basin and the developing solution poured on it as follows: hold the glass between the thumb and finger of the left hand, by the opposite end corner from that in coating with collodion, i. e., 2, and let 3 and 4 be from you.
MANIPULATIONS OF THE POSITIVE PROCESS.
Commence pouring on the developing solution at the end by the thumb, and let it flow quickly and evenly over the entire surface, the first flooding washing off any excess of nitrate of silver there may be about the edges or corners of the glass (if this silver is not washed off, it flows over the edges and on the surface of the impression, producing white wavy clouds of scum), and then hold the glass as nearly level as possible, it having upon its surface a thin covering of solution (care should be observed not to pour the developing solution on the plate in one place, as it would remove all the nitrate of silver and prevent the development of the image, leaving only a dark or black spot where it is poured on). Put down the bottle containing the developing solution, and take up a quart pitcher previously filled with water, and as soon as the outline of the image can be plainly seen by the weak or subdued light of an oil or fluid lamp or candle, pour the water over copiously and rapidly. Continue this until all the iron solution has been removed. If this is not done, the plate will be covered with blue scum on the application of the washing solution. Then the glass can be taken into a light room, and the iodide of silver coating washed off with the cyanide solution, and then rinsed with clear pure water, and stood in a position to drain and dry. I place a little blotting paper under them: it aids in absorbing the water, and facilitates the operation.