# How does dark color absorb light

## Understand physics 4, textbook

19 The world of the visible  Learning objective check 5, page 86 The black sheet and the dark tomato (Fig. 19.1) You need two flashlights from the previous experiment! Darken the room and use the glowing red flashlight to illuminate white paper and then a green leaf. What colors do paper and sheet show? Repeat the experiment with the glowing green flashlight and a red tomato? What color is the tomato? Red light only has the red light components. Therefore the white paper at V3 appears red, the green sheet (almost) black. The green leaf absorbs the red color. Since there is no green color in the red light, you will see the leaf as very dark. The red tomatoes also appear very dark when irradiated with green light and this is also absorbed (swallowed). When printing, the transparent layers of purple (magenta), blue-green (cyan) and yellow are superimposed on the white paper by the inkjet printer. The process that changes the light spectrum takes place before and after the reflection on the paper. The printing inks act like color filters that absorb (swallow, "subtract") the respective complementary color. M Subtractive color mixing: A color filter absorbs the complementary color. Basic colors: purple-red (magenta), blue-green (cyan) and yellow Application: eg printing inks, paints 3. How do the colors of opaque bodies come about? The colors of the objects are determined by which color components of the light they reflect. An apple is red because it reflects the red light components of sunlight and absorbs all other components. You see a black t-shirt as black because it absorbs all colors. The snow is white because it reflects all colors. Plants are green because they reflect the green parts of the sunlight and absorb the red and blue parts. The color of the light is also decisive for the color of the object. In the yellow light of a sodium vapor lamp, all other colors have disappeared - you only see yellow and black. M Opaque bodies or images appear in the mixed colors of the reflected light. V3 19.4 Strong contrasts in sodium light 19.5 Sodium vapor lamps are used in street lighting. White blue white paper blue paper 19.6 cause of the colors of opaque bodies 19.1 the black leaf and the dark paradeiser dark space leaf paradeiser red filter white leaf green filter b) a) 19.2 subtractive color mixing when viewing white light through colored filters Red blue purple yellow green blue-green 19.3 In an inkjet printer, all colors are created by mixing the primary colors magenta, cyan and yellow. For testing purposes only - property of the publisher öbv