By wrapping developing ears of the composition of A B pl with different colored cellophane we found that the sun-red color will not develop when all but red light is excluded

5. By wrapping developing ears of the composition of A B pl with different colored cellophane we found that the sun-red color will not develop when all but red light is excluded, Science 27, Vol. 84, No. 2187, pages 488 and 489. More selective filters have been obtained and we will try to locate definitely in 1937 the wave lengths of light responsible for the production of the sun-red pigment.

W. R. Singleton