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Primary and Secondary Colors

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IMPORTANT! Why YOU should think this is interesting=Edit

The exploration of primary and secondary colors is an intersection of the worlds of art and science combined. Many people associate physics with the memorization of equations and symbols. Even if one does not have a definite understanding of physics, they can still mindlessly manipulate equations on physics tests and manage to pass without being able to explain their answers. While a student who understands the concepts discussed in class does not perform as well on tests because they are lost in a sea of reference table equations. The study of primary and secondary colors can not be defined by a simple equation on the refrence table, deviating from the typical realm of regents physics. Other than the electromagnetic spectrum, there are no equations or facts on the refrence table dedicated to the color wheel. Understanding the application of primary and secondary colors in art and science does not require exemplary skills in science or math, but logical reasoning skills that are useful tools for many situations in life.


Two of the earliest explanations of the optical spectrum came from Newton, when he wrote his Opticks, and from Goethe, in his Theory of Colours.

Isaac Newton first used the word spectrum in print in 1671 in describing his experiments in optics. Newton observed that, when a narrow beam of white sunlight strikes the face of a glass prism at an angle, some is reflected and some of the beam passes into and through the glass, emerging as different colored bands. Newton hypothesized that light was made up of "corpuscles" (particles) of different colors, and that the different colors of light moved at different speeds in transparent matter, with red light moving more quickly in glass than violet light. The result is that red light was bent (refracted) less sharply than violet light as it passed through the prism, creating a spectrum of colors. [1]

major people:Edit

In 1666, Isaac Newton did his first scientific experiments investigating the effect colors produce when a narrow beam of sunlight passed through a prism. Newton classified the collection of colors ranging from violet to red as a spectrum. He inferred that an unevenness in the glass might be producing the spectrum. To test this hypothesis, he cast the spectrum from one prism on to a second prism. Newton thought if the spectrum was caused by irregularities in the glass, then the second prism should have increased the spread of colors. In reality, the second prism reversed the spreading of colors and recombined them to form white light. After more experiments, Newton concluded that white light is composed of an array of colors. We now know that each color in the spectrum is associated with a specific wavelength of light.

Alternative uses of Primary and Secondary colorsEdit

A century after Newton, Johann Wolfgang Goethe began studying psychological effects of colors. Goethe created a color wheel showing the psychological effect of each color. He divided all the colors into two groups – the plus side (from red through orange to yellow) and the minus side (from green through violet to blue). Colors located on the plus side supposedly inspire feelings of excitement and cheerfulness, while colors located on the minus side were associated with weakness and unsettled feelings.[2]

The current form of color theory was developed by Johannes Itten, a Swiss color and art theorist who was teaching at the School of Applied Arts in Weimar, Germany. This school is also known as 'Bauhaus'. Johannes Itten developed 'color chords' and modified the color wheel. Itten's color wheel is based on red, yellow, and blue colors as the primary triad and includes twelve additional hues.

The color spectrum was also used for therapuetic purposes dating back from ancient Egypt to the contemporary treatment of seasonal affective disorder. In the early half of this century, Dinshah Ghadiali, MD PhD, refined a sophisticated system of color therapy. Influenced by a strong background in mathematics and physics, he determined specific "attributes" of the colors of the spectrum have an effect on the human brain when perceived. Later research has confirmed many of his concepts and started new systems for application of light therapy including acupuncture. According to the author, his system connects with traditional Oriental medicine theory, relating colors to the internal organs and meridian system. [3]

'Bold text''''Bold text'Bold text''''==applications of topic== The classification of colored light is divided into two different categories: colors by addition or colors by subtraction. The difference is that the former produces white light when multiple colors are mixed while the later of the two processes has the potential to produce black light when specific combinations of colors are mixed.

====Colors by addition==== : The additive color process consists of the combination of red, green and blue light to form white light. We have already learned that white is not a color at all but rather the presence of all frequencies of visible light [4].

White light can be produced when three distinct frequencies are combined, assuming that they are widely separated on the visable light spectrum. An example of a system that uses the additive process is a color television tube. The TAV has tiny dot light sources of red, green and blue light. When all have the correct intensities, the screen appears to be white. For this reason, red, green and blue light are called the primary colors of light. The primary colors can be mixed in pairs to form a total of three different colors. Red and green light together produce yellow light, blue and green light produce orange light, and red and blue light produce magenta light. The color resulting from the combination of two primary colors is called a secondary color. Secondary colors of light include yellow, orange and magenta. [5]

====Colors by subtraction==== :

In the process of color subtraction, the ultimate color appearance of an object is determined by beginning with a single color or mixture of colors and identifying what color or colors of light are subtracted from the original set A pigment is a colored material that absorbs certain colors and reflects others. The subtraction process is defined by the absorption of light in the formation of colors. Pigments absorb certain colors from white light. A pigment that absorbs a specific primary color from white light is classified as a primary pigment. For instance, yellow pigment absorbs blue light and reflects red and green light. A pigment that absorbs two primary colors and reflects one is called a secondary pigment. If a primary pigment is mixed with a secondary pigment all light will be absorbed, no light will be reflected and the result will be black.

[6] [7]

Visible light in the Electromagnetic SpectrumEdit

Primary and secondary colors correspond to different wavelengths of light. These wavelengths are illustrated on the Electromagnetic Spectrum. The visible part of the electromagnetic spectrum exists between Ultraviolet light and Infrared. Monochromatic light consists of light of a single color, light of a single wavelength or frequency. If all the colors of visible light are mixed together, the result is white light. Black is the complete absence of visible light.[8]

practice problemsEdit

1.Magenta light shines on a sheet of paper containing a yellow pigment. Determine the appearance of the paper.

explination: Magenta light consists of red light and blue light. A yellow pigment is capable of absorbing blue light. Thus, blue must be subtracted from the light which shines on the paper. This leaves red light. If the paper reflects the red light, then the paper will look red. M - B = (R + B) - B = R [9]

2.Yellow light shines on a sheet of paper containing a blue pigment. Determine the appearance of the paper.

explination:Yellow light consists of red light and green light. A blue pigment is capable of absorbing yellow light; that is, blue paper can absorb both red and green primary colors of light (recall that yellow light is a mixture of red and green light). So red and green light shine on the paper; and both the red and the green light must be subtracted. There is no color left to be reflected to the eye. Subsequently, the paper appears black. Y - Y = (R + G) - (R + G) = No reflected light = Black [10]

3.Yellow light shines on a sheet of paper containing a red pigment. Determine the appearance of the paper.

Yellow light consists of red light and green light. A red pigment is capable of absorbing cyan light; that is, red paper can absorb both green and blue primary colors of light (recall that cyan light is a mixture of green and blue light). So red and green light shine on the paper; and green light must be subtracted. (There is no need to worry about blue light since blue light is not shining on the paper.) This leaves red light to be reflected. If the paper reflects the red light, then the paper will look red. [11]


1. - Background information on the creator of the color wheel

2. - Simple explanation of the difference between additive and subtractive colors

3. - color subtraction

4. - color addition

5. - background information on the visible spectrum

6. - history of topic


1. - history of the phychology of color associations and how they led up to the creation of the color wheel

2. - alternative functions of the color spectrum

3. Glencoe Physics Textbook Zitzewitz, Paul. Glencoe Physics; Principles and Problems. McGraw-Hill Companies, Ohio; 1999. Useful diagrams of primary and seconday colors

4. Barron's Regents Review Book Lazar, Miriam A. Barron's Review Course Series Let's Review: Physics: The Physical Setting. 3 ed. New York: Barron's Educational Series, 2005. - Information on additive and subtractive properties

5. Brief Review in Physics The Physical setting Walker, Matt. Prentice Hall. Pearson Education, New Jersey; 2003 - an explanation of light and the electromagnetic spectrum

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