Photographic optics and colour photography : including the camera, kinematograph, optical lantern, and the theory and practice of image formation / by George Lindsay Johnson.

George Lindsay Johnson

Date:: 1909

Credit: Photographic optics and colour photography : including the camera, kinematograph, optical lantern, and the theory and practice of image formation / by George Lindsay Johnson. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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$8. TABLE FOR ENLARGEMENTS. Times of Enlargement and Reduction. \ OCUS of Lens. 1 2 3 4 5 6 7 8 in. 3 in. 6 6 in. 9 H in. 12 4 in. 15 3| in. 18 3.1 in. 21 31 in. 24 3f in. 27 31 33 7 7 101 14 4! 171 H 21 41 24^ ±A 28 4 31i 3}§ 4 8 8 12 6 16 20 5 24 H 28 H 32 36 41 9 9 13.1 18 6 22.1 5§ 27 51 311 51 36 5* 401 5 10 10 15 71 20 61 25 6] 30 6 35 5| 40 5f 45 5| 11 11 161 8\ 22 71 271 33 6§ 38^ DT5 44 6? 49,1 6 12 12 18 9 24 8 30 71 36 7i 42 7 48 6f 54 6| 7 14 14 21 10J 28 35 8| 42 81 49 56 8 63 71 8 16 16 24 12 32 10g 40 10 48 91 56 9^ 64 9} 72 9 9 18 18 27 131 36 12 45 11* 54 10| 63 101 72 lOf 81 10^ 10 20 20 30 15 40 131 50 121 60 12 70 11§ 80 11? 90 HI 11 22 22 33 161 44 141 55 131 66 131 77 121 88 12j 99 12f 12 24 24 36 18 48 16 60 15 72 141 84 14 96 13* 108 131 The first vertical column gives the focus of the lens. The top horizontal row shows the number of times the picture has to be enlarged or reduced. The square where the horizontal row meets the enlargement colours contains the two figures required. For enlarging, the upper figures in the square give the number of inches the centre of the lens must be removed from the screen or plate; the lower, the distance of the lens from the picture to be copied.$