Convergence Controls

When you take a picture with your camera pointed up or down, vertical lines in the picture appear to be converging. You can correct this when you make an enlargement from the negative.

First tilt the enlarger easel by lifting up one edge until the vertical lines in the projected image appear parallel. Then place something under that edge to hold the easel in place. Focus the image at a point one-third of the way in from the high edge. If you need to make only a slight correction, you can keep the image in focus over the entire picture area by using a small enlarger lens opening. However, if the easel is tilted at a considerable incline, you must tilt the negative carrier to keep the image in focus. (If it’s not possible to tilt the negative carrier in your enlarger, you won’t be able to correct severe converging lines.) Tilt the negative carrier until the complete image on the easel appears sharp.

Incidentally, when you tilt the enlarger easel to correct converging vertical lines, you will probably encounter a slimming effect on your subject. When the easel is tilted, the proportions on the print will equal those in the original scene only when the enlarger lens-to-negative distance is equal to the camera lens-to-film distance when the picture was made. Since the enlarger lens is likely to have approximately the same focal length as the camera lens, the enlarger lens-to-negative distance is likely to be greater than the lens-to-film distance (due to the shorter subject distance involved in enlarging). With the easel tilted, you’ll get a greater magnification of height than width, resulting in the slimming effect. However, the slimming is usually less objectionable than converging lines that should be parallel.