Before opening the package of Bromide paper see that no white light enters the room. It is well to provide a good sized box with a hinged, light tight cover to keep the Bromide paper in until needed, with also a compart ment to hold the exposed sheets when making a number of enlargements to be developed later.
After the correa size and focus have been obtained the next step is the exposure.
Provision should have been made for a non-adtinic yellow or orange dark-room lamp, or a small window opening outside covered with several thicknesses of yellow or post office paper.
In first attempting the making of enlargements, test strips for deter mining the accuracy of focus and proper duration of the exposure should be employed.
A strip one or two inches wide and long enough to extend diagonally across the focused image will be sufficient.
Correa exposure depends on several faaors ; the intensity of the light, density of the negative, size of the enlargement, and aperture of lens.
The first test exposure will be purely arbitrary ; if the light be good and the negative of average density, say ten seconds.
Cover up two-thirds of the strip with a piece of cardboard, and expose for five seconds, move the cardboard and give the next portion five seconds, making ten for the first, then remove the cardboard entirely and expose the remainder of the strip five seconds, the fully exposed strip will now contain three different exposures, one of five seconds, one of ten and one of fifteen seconds.
While the exaa time for the developement of a corredily exposed bro mide enlargement cannot be given, the proper exposure may be readily de termined by appearance as the image will appear gradually, developing brilliantly and attaining full strength in about one minute. Develop this test strip (see page 134 for direaions.) If these test exposures are all very much over or under exposed make another set of test exposures, being guided as to time by the first strip. If the image comes up rapidly but dull and full of detail in the highlights it has been over-exposed ; if weak and without detail, it is under-timed. Linder different conditions the time required for exposure varies from five seconds to five or ten minutes, according to the light, density of the negative, etc. However, a few trials
will narrow the exercise of judgment down to the intensity of the light, and the making of correct exposures becomes a simple matter.
In making enlargements of different sizes it must be remembered that light intensity decreases as the easel is moved further away from the lens. As an example : If an enlargement eight by ten in size requires ten sec onds, one sixteen by twenty (which is four times as great in area) would require four times ten or forty seconds exposure. Do not attempt to count seconds ; use a watch or clock.
No printing process affords so many opportunities for modifying in the print the characteristics of the original negative as bromide enlarging.
Stop down the lens so as to afford plenty of time during the exposure, and we can shade a little here, give a little longer exposure there and ob tain just the result desired, bringing out detail in the shadows or softening a highlight at will.
In shading any portion during exposure, hold the shade nearer the lens than the copy board to avoid sharp lines and obtain the proper diffusion.
After the exposure has been made the next step is development, which is accomplished in practically the same manner as in the development of a plate or film.
Provide a ruby or orange lamp, graduate, stirring rod and three trays, preferably of hard rubber, or rubber lined, at least an inch larger each way then your sheets of bromide paper, to facilitate handling.
A rubber lined tray of any size is easily constructed by glueing a sheet of gossamer rubber cloth into a wooden box or tray.
As the bromide paper is not as sensitive to light as a dry plate or film a stronger light may be employed for developing. A small window opening outside, covered with two thicknesses of yellow post office paper will serve, or the ruby glass may be removed from the dark room lamp. The remain ing orange glass will be ample protection against fog and allow the process of development to be observed with greater ease.