Page:Proceedings of the Royal Society of London Vol 69.djvu/54

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No. 27. Filter curves for inks with abrupt absorptions at X 49 and X 59. The ordinates show the percentage area to be left free from ink, and therefore indicate the opacity to be obtained on the corresponding negative, or for au orthochromatic plate the transparency of the filter.

Absorptions at 57 - 5 and 5O5.

Percentage area left uncovered by ink.

Wave-length.

Excess of white.

Yellow.

Pink.

Blue.

38 8-5

1-1

1-1

40 24 '6

3-3

3-6

42 42 -2

5-1)

6-4

44 63'7

9-0

9-6

40 61 -(5

5-5

6-0

48 49-3

6-3

2-2

50 35 -7

28-0

6-8

52 19 -9

82-8

23-4

54 5 -3

93-8

10-7

56

78-5

21-7

7-0

58

45-8

57-0

5-2

60

5-1

79-0

0-6

62

16 5

86-0

22-2

64

11-2

46-0

15-2

66

4-2

18 5-9 63 0-6 5-9 1-9 70 0-2 2-0

0-6

128 -4

The total excess of white is about the same, but the distribution is not so good, as the ends of the spectrum, when the luminosity is small, have large excesses.