Subtractive Colors SE

Name: Date: Student Exploration: Subtractive Colors Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. [NOTE TO TEACHERS AND STUDENTS: This lesson was designed as a follow-up to the Additive Colors Gizmo. We recommend you complete that activity before this one.] Vocabulary: absorb, CMY value, complementary color, cyan, magenta, primary colors, reflect, RGB value, secondary color, subtractive color, transmit Prior Knowledge Questions (Do these BEFORE using the Gizmo.) A color printer can print any color by mixing three primary colors of ink: cyan (light blue), magenta (bright pink), and yellow. 1.​ What color do you think you would get if you mixed cyan and magenta? blue 2.​ What color do you think you would get if you mixed cyan and yellow? green 3.​ What color do you think you would get if you mixed magenta and yellow? red Gizmo Warm-up We see objects when light from that object enters our eyes. Some objects produce their own light, while others transmit or reflect light. The Subtractive Colors Gizmo allows you to explore how light is absorbed and reflected by colored pigments such as paint. Three primary colors of light—red, green, and blue—combine to make white light. Turn on Show RGB values at the mouse location to see how much red, green, and blue is in each color. 1.​ Move the cursor over a white area. What is the RGB value of white? 255,255,255 2.​ Move the cursor over the cyan circle. What is the RGB value of cyan? 0,255,255 3.​ Assume the cyan circle is a painted spot that is illuminated by white light. Some of the white light is absorbed by the cyan pigment, and some is reflected into your eyes. A.​ What colors of light are reflected by the cyan spot? The colors reflected by cyan are blue and green. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved​ B.​ What color of light is absorbed by the cyan spot? Activity A: The colors reflected by cyan is red. Get the Gizmo ready: ●​ Turn on the Cyan, Magenta, and Yellow circles. ●​ Check that each color value is set to 255. Mixing primary colors Question: What happens when cyan, magenta, and yellow pigment are combined? 1.​ Gather data: Move the cursor over the magenta and yellow spots. Record the RGB value of each pigment, and then state which colors are absorbed and reflected by each pigment. Pigment RGB value Reflected colors Absorbed color Cyan 0, 255, 255 Green, blue Red Magenta 255, 0, 255 Red, blue Green Yellow 255, 255, 0 Green, red Blue 2.​ Observe: Secondary colors are created when two primary colors are mixed together. Which colors result from each of the following pigment combinations Cyan and magenta: blue Cyan and yellow: blue Magenta and yellow: red Cyan, magenta, and yellow: black 3.​ Analyze: Consider the combination of cyan and magenta. A.​ What color of light does both cyan and magenta reflect? Cyan and Magenta both reflect blue. B.​ What color results from mixing cyan and magenta pigment? Mixing cyan and magenta makes blue. C.​ What colors of light are absorbed by the combination of cyan and magenta pigment? (2 answers) Red and Green 4.​ Summarize: Explain the result of each color combination based on the colors that each pigment absorbs and reflects. Cyan and yellow: Cyan and yellow make green. Magenta and yellow: Magenta and yellow make red. Cyan, magenta, and yellow: Mixing all three colors makes black. ​ Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved​ Get the Gizmo ready: Activity B: ●​ Check that the Cyan, Magenta, and Yellow values are 255. ●​ Check that Show RGB values is on. Creating colors Introduction: When more light is added to a mixture, the resulting color becomes lighter. When more pigment is added to a mix, the resulting color becomes darker. For this reason, colors formed by mixtures of pigment are called subtractive colors. Question: How is the RGB value of a pigment mixture determined? 1.​ Observe: Overlap the magenta and yellow circles to make a circle of red. Then move the cyan circle over the red circle. What is the result of combining red and cyan pigment? After following these instructions I created black. 2.​ Investigate: Because they combine to make black, red and cyan are called complementary colors. Use the Gizmo to determine the complementary colors of magenta and yellow. Blue and yellow are complementary colors, and green and magenta are complementary colors. 3.​ Gather data: Move the three circles so they completely overlap each other. Use the sliders to create each of the described colors in the table below. Record the resulting RGB value. Color Cyan Magenta Yellow R G B Dark green 255 180 255 0 75 0 Tan 45 75 115 210 180 140 Blue-gray 80 60 45 175 195 210 4.​ Analyze: For each color in the table above, compare the cyan, magenta, and yellow values (CMY values) to the RGB values. A.​ What is the relationship between the cyan value and the red value? The cyan minus the number input in for cyan is equivalent to red. B.​ What is the relationship between the magenta value and the green value? The magenta minus the number input in for magenta is equivalent to green. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved​ C.​ What is the relationship between the yellow value and the blue value? The yellow minus the number input in for yellow is equivalent to blue. 5.​ Calculate: Use the Gizmo to check your answer. What is the RGB value of a color with a CMY value of 30, 100, 0? 225, 155, 255. 6.​ Summarize: In general, if you are given the CMY value of a color, how can you calculate the RGB value of the color? If I take the CMY value minus the 255 of each color, you get your RGB value. 7.​ Explore: Use the Gizmo to create a color matching each description. List the CMY value and RGB value of each color. Describe your own object and color in the last line of the table. Description CMY value RGB value A dark blue night sky 255, 255, 145 0, 0, 110 A gray cloud 135, 125, 115 120, 130, 140 An orange pumpkin 20, 110, 255 235, 145, 0 A green olive 215, 195, 255 40, 60, 0 A red brick 50, 255, 255 205, 0, 0 Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved