Appearance of coloured objects in coloured light
A convenient source of light of various colours may be obtained by placing an ordinary electric lamp in a box with an opening which may be covered with gelatine sheets of different colours. By means of such a lamp the appearance of different
coloured objects in different colours of light may be examined in a dark room. Then it is found that red bodies look red in red light while green and blue ones look black, since they have absorbed the red light. In like manner a red poppy appears black in green light. On the other hand, the compound yellow petals of a daffodil appear black only in blue or violet light. The daffodil appears yellow only in yellow or white light. In red light it looks red and in green light, green.