Additive Color

color UNIT III: Additive Color

Project IIID
Mixing Light

Objectives
Studio Fundamentals: To gain experience in the use of additive light techniques. To use computers as a tool for evaluating the effects of RGB color (via studio lighting, digital photography, Adobe PhotoShop).

Concept: To gain experience in working as part of a collaborative team.

Project Overview Working as part of a collaborative team, photographs of a still life are shot under specific red, blue, and green light sources and reassembled using Photoshop to produce a single white-balanced image.

References for further study

Zelanski and Fisher, Color, pages 77 - 86.
Adobe PhotoShop help menu
http://www.bamagazine.com/RGB/
http://www.wackerart.de/mixer.html
http://www.efg2.com/Lab/Graphics/Colors/index.html
http://www.bway.net/~jscruggs/index3.html
http://www.adobe.com/education/pdf/exchange/color_theory_curriculum.pdf

Vocabulary electromagnetic spectrum, prism, white light, visible spectrum, light mixing, Kodak Wratten filters; process colors (printer's CMYK inks), , additive light mixing, wavelength, RGB (red, green, blue), CRT (cathode ray tube), temperature balance, PhotoShop, color channels

Materials Still life with a good range of colors constructed by teams. Digital camera with tripod. Wratten filters. Three slide projectors. Photoshop. Alt: Color acetate sheets. Overhead projector.

Process
Preliminary:

Before coming to class, review the thematic concept of Collaboration as found on the website. Also read the discussion Additive Color for Unit III. Review the Project References and Vocabulary above.

Activity:

Step One: As a member of a collaborative team, create an interesting Still Life with a good range of values and hues.

Step Two: Frame the scene in the viewfinder of a digital camera mounted on a tripod.

Step Three: Photograph the same scene four times--once using temperature balanced white light and three more times using each of three RGB Wratten filters. Each team should produce: 1) A "regular" color photograph using color balanced white light; 2) A "red" photograph using a Kodak Wratten filter over a white light source; 3) A "green" photograph using a Kodak Wratten filter over a white light source; 4) A "blue" photograph using a Kodak Wratten filter over a white light source.

Step Four: Reassemble three colored digital photographs in Photoshop to produce an image that matches as closely as possible the original photograph taken under white light.

1. Open the red, green, and blue images in Photoshop.
2. Open a new document with a black background that is slightly larger than the three images.
3. Use the move tool (v) to drag each image into the new document. This will automatically put each image on a separate layer.
4. In the layers palette, click on one of the image layers and change the blending mode (use the drop down menu at the top of the palette) to "lighten."
Repeat this procedure for the other two image layers.
5. Use the move tool to register the three images. The resulting composite should appear close to neutral.

Alternative outcome: Using a standard ink jet printer, print out each color channel (R,G,B) from Photoshop onto separate clear acetate sheets. Use three overhead projectors to demonstrate additive color mixing by overlapping three projected images.

Discussion and Critique Ideas
Students learn primarily by hands-on involvement in this assignment, and also by seeing the additive light mixing happen before their eyes--both with the projected light sources and in Photoshop.

Points to discuss may include the following:

How does the original "white light" photograph compare with the photograph produced by combining the three differently colored RGB photographs?
What is the relationship of RGB color to CMYK color?
How do Lighting Designers use additive light principles?
How does a cathode ray tube (i.e., video monitor) utilize RGB?

Return to UNIT III Overview

Project IIID	*Mixing Light*
Objectives	Studio Fundamentals: To gain experience in the use of additive light techniques. To use computers as a tool for evaluating the effects of RGB color (via studio lighting, digital photography, Adobe PhotoShop). Concept: To gain experience in working as part of a collaborative team.
Project Overview	Working as part of a collaborative team, photographs of a still life are shot under specific red, blue, and green light sources and reassembled using Photoshop to produce a single white-balanced image.
References for further study	Zelanski and Fisher, Color, pages 77 - 86. Adobe PhotoShop help menu http://www.bamagazine.com/RGB/ http://www.wackerart.de/mixer.html http://www.efg2.com/Lab/Graphics/Colors/index.html http://www.bway.net/~jscruggs/index3.html http://www.adobe.com/education/pdf/exchange/color_theory_curriculum.pdf
Vocabulary	electromagnetic spectrum, prism, white light, visible spectrum, light mixing, Kodak Wratten filters; process colors (printer's CMYK inks), , additive light mixing, wavelength, RGB (red, green, blue), CRT (cathode ray tube), temperature balance, PhotoShop, color channels
Materials	Still life with a good range of colors constructed by teams. Digital camera with tripod. Wratten filters. Three slide projectors. Photoshop. Alt: Color acetate sheets. Overhead projector.
Process	Preliminary: Before coming to class, review the thematic concept of Collaboration as found on the website. Also read the discussion Additive Color for Unit III. Review the Project References and Vocabulary above. Activity: Step One: As a member of a collaborative team, create an interesting Still Life with a good range of values and hues. Step Two: Frame the scene in the viewfinder of a digital camera mounted on a tripod. Step Three: Photograph the same scene four times--once using temperature balanced white light and three more times using each of three RGB Wratten filters. Each team should produce: 1) A "regular" color photograph using color balanced white light; 2) A "red" photograph using a Kodak Wratten filter over a white light source; 3) A "green" photograph using a Kodak Wratten filter over a white light source; 4) A "blue" photograph using a Kodak Wratten filter over a white light source. Step Four: Reassemble three colored digital photographs in Photoshop to produce an image that matches as closely as possible the original photograph taken under white light. 1. Open the red, green, and blue images in Photoshop. 2. Open a new document with a black background that is slightly larger than the three images. 3. Use the move tool (v) to drag each image into the new document. This will automatically put each image on a separate layer. 4. In the layers palette, click on one of the image layers and change the blending mode (use the drop down menu at the top of the palette) to "lighten." Repeat this procedure for the other two image layers. 5. Use the move tool to register the three images. The resulting composite should appear close to neutral. Alternative outcome: Using a standard ink jet printer, print out each color channel (R,G,B) from Photoshop onto separate clear acetate sheets. Use three overhead projectors to demonstrate additive color mixing by overlapping three projected images.
Discussion and Critique Ideas	Students learn primarily by hands-on involvement in this assignment, and also by seeing the additive light mixing happen before their eyes--both with the projected light sources and in Photoshop. Points to discuss may include the following: How does the original "white light" photograph compare with the photograph produced by combining the three differently colored RGB photographs? What is the relationship of RGB color to CMYK color? How do Lighting Designers use additive light principles? How does a cathode ray tube (i.e., video monitor) utilize RGB?