Early Work In Photography
A Text-book For Beginners

8 Early Work in Photography. tive paper. Take a small piece (say an inch ‘square), put it face (or shiny side) up on a book, and cover one half of it with any opaque substance, such as a piece of cardboard, then remove it to the window, and expose it for a minute to daylight. Then lift the cardboard, and notice the differ- ence in color between the part that was protected from, and the part that was exposed to, dayliglit. In one minute this will probably be slight, but, if you replace the card and expose the paper again for five minutes, a great change will be noticeable: you will observe that one half the paper is white (having been protected from the action of light), while the other half has turned to a deep reddish brown. Photo- graphy is founded upon this action. You will also notice that the paper, as you buy it from the dealer, is enclosed in a red or orange-coloured wrapper ; this is done to protect it from the action of light, because a ruby coloured or yellow light does not exert the same action as white or blue light. In dealing with gelatino-chloride printing-out paper, it is only necessary to handle it in a diffused light (about five or ten feet from the window in an ordinary room), and to keep the stock of paper stored in a light-tight box, or in ar opaque envelope. Having satisfied yourself as to the effec of light upon sensitized paper, and tlie necessity tor pro tecting unused paper from its action, we will now under take a more interesting experiment, which will further de- monstrate tliat varying degrees of density depend upon the varying amount of light admitted to the paper. Take a piece of glass tlie size of the quarter-plate printing frame (31 x 4^ inches) and paste upon it half-a-dozen pieces of tissue paper (each one half-an-inch longer than tlie rest), as in the diagram on page 9. No. i being covered with one thickness of tissue, No. 2 with two thicknesses, and so on. Then put the sheet of glass (paper-covered side downwards) into tlie printing frame, next cover the glass with a sheet of sensitive paper—being careful to place the coated (or shiny) side of the paper downwards—and re-adjust the back (hinged part) of the frame in its place. You will note that the pressure of the springs holds the back of tlie frame firmly in place, and, of course, presses the paper firmly to the glass, thus ensuring perfect contact. Now remove the frame and its contents to bright daylight, and expose tlie paper-covered glass thereto, for about fifteen minutes. After exposure, remove it into a shady place (the interior of a room, for instance) and examine the course of the printing. To do this, without moving the paper, requires a little care at first, but is really very simple.