This will be the part of the spectrum absorbed by the pink ink. From X 59 to the end of the spectrum they were
Violet, 0. Green, 15-6. Ked, 65-8.
These add up to
Violet, 148-2. Green, 148 -4. Ked, 148 '3.
Thus the ray compositions of the inks are
Yellow ink. Blue ink. Pink ink.
Violet 25-8 148-2 122-4
Green 143-6 132-8 20-4
Ked 145-3 82-5 68-8
The blue ink matches A 50 -4 and white, and the yellow will match X 58 with white.
I now took the ray composition of some spectrum colour, and found by successive approximation the area to be covered by the inks to match it. Thus X 44 has a ray composition of
Red 1-47 equivalent to Ked 1-27
Green 0-20 ' Green 0-0
Violet 76-68 Violet 76-48
White 0-2
Then if 66 per cent, of the area is free from yellow ink, 66 per cent, of the light the yellow would absorb will be transmitted, namely
Red, 0. Green, 1-2. Violet, 76-6. White, 2.
So if 5 per cent, of the area is left free from blue ink it will reflect in addition
Red, 3-2. Green, 0-78.
The pink ink must be printed all over. Then we shall have left- Red 3-2 equivalent to Red....- 1-22
Green 1'98 Green O'O
Violet 78-6 Violet 76-46
White 2-0 White 3-98
which matches the spectrum colour except for an excess of 3'7& white.
In the same way I worked out the percentage areas to be left free from colour to match each of the wave-lengths 38, 40, 42, &c., up to 70, and have found in each case the excess of white.
