USE OF DAYLIGHT ENLARGING APPARATUS.
To use the apparatus, proceed as follows the printing frame with a plate or paper. The opening c must be recessed or have a beading to prevent the negative falling through. It will be seen that, as there is but a slight ad justment of the focus, only one size of en largement can therefore be made ; so that, before constructing such an appara tus, it is necessary to decide what the amount of magnification is to he, and to ascertain the focal length of the lens. Suppose the negative to be quarter plate, and it is desired to enlarge to whole plate ; then there will need to be three times the focal length between the lens stop and printing frame, and half this distance between lens stop and negative. The top n may be made to sheet of clean white paper as just described, and place in the position in dicated. Insert the negative—film down wards—in the opening c (if a film is being dealt with it should be placed be tween two clean pieces of glass, which may be held together with gum paper or a rubber hand). In any case the side actually bearing the image must be to wards the sensitive material, or a re versed picture will result. The door E is now opened, and if necessary covered with a cloth, and the adjustment used until the image appears sharp, when the door may be closed. The frame may then be taken to the dark room, the plain paper replaced by bromide, and the shutter closed. After inserting this in the camera, cover the opening c and remove the shutter. The necessary exposure is given
by uncovering the opening c. The fore by Fig. 423, which is of fixed focus, ami the similar but more finished arrangement illustrated by Fig. 424. Fig. 425 shows a highly ingenious design in which the going deals with a home-made apparatus, but similar enlargers may now he had of almost all dealers. Fig. 422 shows a far better and more usual form of apparatus, but of course more costly and less likely to be found convenient by the majority of distances between the negative, the lens, and the paper are always proportionally adjusted, so that an enlargement of any size within the compass of the camera can be obtained in correct focus by a simple turn of the screw. In the illustration will amateurs. In an improved construction, and with certain additions to be described later, it forms the apparatus in use in all professional establishments. Various forms of daylight enlargers are described and illustrated on pp. 39 and 40 : in addition to these may be mentioned the simple and inexpensive apparatus shown be noticed a parabolic reflector, provided for use with incandescent gas if desired: This is detachable when daylight is em ployed, and is shown separately by Fig. 426. The two gas burners are screened by the side wings of the reflector, and the light can he regulated from the outside by taps provided for the purpose.