This is the very simplest and one of the most useful kinds of photography. You need but very little material to make the pictures with and the little you need will cost less than a dollar.

The Materials Required

Buy, or you can make, (1) a 5 x 7 printing frame as shown in Fig. 55 and get a sheet of clear glass to fit it, and (2) a couple of dozen sheets of 5 x 7 blue-paper41 which you can buy at any photographic supply house.

Now take one of the drawings you have made on tracing paper or on tracing cloth with India ink as I described in the last chapter and lay it with its inked surface on the glass; lay on this a sheet of blue-paper with its sensitised side on the tracing paper or cloth; put the back of the printing frame on top of the blue-paper, press the springs into place and set the frame in the sunlight.

Every few minutes open a half of the hinged back of the printing frame and take a look at the blue paper to see if the printing is far enough along. When the lines of the drawing show plainly on it take the print out of the frame and wash it, as it is called, by letting water run on it or by putting it through several changes of water.

When it is well washed hang it up on a line by a corner to dry and you will have a good, clear print with white lines on a blue ground. In this way by using a negative that you have made with a camera, especially if it is a marine view, you can get some very pretty and artistic pictures.

41 You can make blue print paper by dissolving ammonium ferric citrate in warm water and coating the surface of the paper with it by floating it on top of the solution.