A collodion plate is now prepared and well drained; then one of the transparent screens is fixed in front of the carrier by drawing pins, by passing strips of gum paper over, or by fixing with fine tacks a piece of thin card at the top, and one at the bottom, slightly overlapping the screen, and holding it firmly in a sort of rebate.
The carrier is now placed in the dark slide, the sensitive plate in its place, the door of the slide closed and fastened.
The exposure is now made in the camera, and if the screen is properly transparent the time will not be very much more than when copying in the ordinary way.
The development of the exposed plate is done by means of the developer given in Chapter I., and the result must have all the details of the photograph, while the lines of the screen must be clear and free from veil.
The negative is washed, fixed in cyanide, washed again and then intensified, first immersing it in the solution No. 1, Chapter I., until bleached, then thoroughly washed and blacked with No. 2 solution, again washed, and varnished with the water varnish, or dried and varnished with benzole varnish.
For the second method we shall require, instead of a paper photograph, a transparency on glass. {67}
The transparency may be made on a gelatine dry-plate by printing in contact with the negative, or an enlarged transparency may be made, either on a dry plate or by the wet collodion process.
The transparency should be made by contact, when the original negative is of larger size than the block required; the enlarged transparency is used if the negative be smaller or the same size as the block.
The development of the transparencies on gelatine dry-plates will be treated of later, but if wet collodion be used, the manipulations will be the same as for negatives, except that the image is in reverse gradations, the lights being clear glass, and the shades dense and black. Every detail in lights, shadows, and half-tones must show distinct and strong.
