4. basics of colour science, digital colour communication

8/11/2019 4. Basics of Colour Science, Digital Colour Communication

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Color is an effect produced by the eye and its nerves by

light waves of different wavelength or frequency. Lighttransmitted from an object to the eye stimulates thedifferent color cones of the retina, making possibleperception of various colors in the object.

Since the colors that compose sunlight or white lighthave different wavelengths, the speed at which theytravel through a medium such as glass differs; red

light, which has the longest wavelength, travels fasterthrough glass than blue light, which has a shorterwavelength.


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When white light passes through a glassprism, it is separated into a band of colorscalled a spectrum. The colors of the visiblespectrum are usually called red, orange,

yellow, green, blue, indigo, and violet. Thephrase ROY-G-BIV is an easy way toremember this. This same effect happens

when light goes through water droplets orrain causing us to see a rainbow.

Our eyes are sensitive to light which lies ina very small region of the electromagnetic

spectrum labeled "visible light." Thisvisible light corresponds to a wavelengthrange of 400 - 700 nanometers (nm) and acolor range of violet through red. Thehuman eye is not capable of seeing

radiation with wavelengths outside thevisible spectrum


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Additive Color

Colors whose beams of light in various combinationscan produce any of the color sensations are calledprimary, or spectral, colors. The process of combining

these colors is said to be additive: the sensationsproduced by different wavelengths of light are addedtogether. The additive primaries of light are are red,green, and blue-violet. White can be produced by

combining all three primary colors. Any two colorswhose light together produces white are calledcomplementary colors, e.g., yellow and blue-violet, orred and blue-green.


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Subtractive Color

When pigments or dyes are mixed, the resulting sensationsdiffer from those of the transmitted primary colors. Theprocess in this case is subtractive, since the pigmentssubtract or absorb some of the wavelengths of light. Withtransparent dyes, like our Fiber Reactive Dyes that we use

for Tie-Dye, Cyan (blue-green), Magenta (red-violet), andYellow and are called subtractive primaries, or primarycolors. This is called the CMY system, and you use a CMYcolor wheel. (With more opaque pigmented products, likeour fabric paints, use traditional Red, Yellow and Blue asprimaries and use a Red, Yellow, Blue color wheel.) A

mixture of cyan and yellow pigments yields green, the onlycolor not absorbed by one pigment or the other. A mixtureof the three primary pigments produces black. Thesesubtractive primary colors are the ones we use whendyeing, and the Fiber Reactive Dye equivalents are

Turquoise, Fuchsia, and Lemon Yellow.


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PROPERTIES OF COLOR

The scientific description of color, or colorimetry,includes all of the relevant properties of a colorsubjectively and objectively. The subjective descriptionincludes the hue, saturation, and lightness orbrightness of a color.


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HUE refers to what is commonly called color, i.e., red,green, blue-green, orange, etc.

SATURATION refers to the richness of a hue as

compared to a gray of the same brightness; this is alsoknown as chroma.

VALUEmeasures the brightness of an opaque objecton a scale from dim to bright or from black to white.


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Types of Color Primary Colorsare the colors that mix together to

make all the Secondary Colors, magenta, cyan & yellow.

Secondary Colors are the colors you get when you mix

Primary Colors: orange, green & purple.

Tertiary Colorsare the in-between colors like red-orange or yellow-green Theyre made by mixing oneprimary color and one secondary color together. Thereare endless combinations of tertiary colors, dependingon how theyre mixed.


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Complementary Colors

Magenta and green, cyan and orange, purple andyellow. These are the colors directly across from eachother on the color wheel. Theyre calledcomplementary because, when used together, they

become extremely vibrant and have a lot of contrast.Complementary colors are useful when you want tomake something stand out.


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Analogous Colors

Red and orange, blue and green, etc. These arecolors right next to each other on the color wheel.They usually match extremely well, but they have littlecontrast. Theyregood for very serene-feeling designs

and artwork where you want viewers to feelcomfortable.


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4. basics of colour science, digital colour communication

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