Chapter 8 Color Science, Vision, and Space

What is the composition of white light?

A combination of roughly equal measures of all the visible wavelengths.

What is the additive color formation system?

A system in which the primary additive colors (RGB) mix to form other colors. White is formed by adding the three colors in equal measures.

______ is the adjustment our eyes make to light conditions.

Adaptation

adaptation

Adjustment that the eyes make to their sensitivity of light.

saturation

Attribute of color that defines its degrees of strength or difference from white. It can also be defined as the extent to which one or two of the three RGB primaries predominates in a color.

What are the subtractive primary colors?

Cyan, magenta, and yellow

Name four color measurement instruments and what they measure.

Densitometer measure optical density, colorimeters measure color values; spectrophotometers measure lightwaves; spectrodensitometers measure optical density, color values, and lightwaves.

Identify the three criteria used in the HSB color system.

Hue, saturation, and brightness

What three color attributes are identified in Munsell's color system?

Hue, value, and chroma

What are Pantone colors based on?

Ink colors common to the printing industry.

What do the letters LAB represent in the CIELAB color model.

L represents brightness, A indicates the red to green value, a B represents the yellow to blue value.

brightness

Often referred to as lightness or luminosity, it can be defined as a value indicating how light or dark a color is. For paper classification, the percent reflectance of blue light only, centering on the wave length of 457 nm.

additive primary colors

Red, green and blue. When mixed together in varying combinations and intensities, these three colors of light can produce any other color. Usually referred to as the RGB system.

What can happen to light when it reaches a surface or boundary between two types of material?

Some of the light may reflect, while some may pass through the surface. Light entering the second material may refract. Some of the light may be scattered or absorbed.

value

Term used in the Munsell system of color notation to describe the lightness or darkness of a color. It is shown on the central axis as nine visible steps. The darkest value is at the bottom and the lightest value is at the top. The value of pure black is designated as 0/, pure white as 10/, and middle gray is 5/.

chroma

Term used in the Munsell system to indicate the extent to which the color is diluted by white light. It shows the amount a given hue deviates from a neutral gray of the same value.

What does the acronym RGB represent?

The additive primary colors, red, green, and blue.

What is saturation?

The attribute of color that defines its degree of strength or difference from white. It can also be defined as the extent to which one or two of the three RGB primaries predominates in a color.

hue

The color of an object perceived by the eyes, and determined by the dominant light wavelengths reflected or transmitted.

electromagnetic spectrum

The entire range of wave lengths of electromagnetic radiation, extending from gamma rays (very short) to radio waves (very long). The wavelengths are usually measured in nanometers (nm).

In Munsell's color system, what does the term chroma identify?

The intensity or strength of a color and its saturation.

Which part(s) of the eye determine(s) our perception of light and color?

The light sensitive nerve cells of the retina known as rods and cones.

What is color separation?

The process of dividing a color image into the CMYK process colors that will be used to prepare the four printing plates.

visible light

The range of wavelengths of the electromagnetic spectrum (400 nm - 700 nm) that cause the sensation of vision.

What is a color triad?

Three colors an equal distance apart on the color wheel.

Why is the black ink used as a fourth printing channel?

To ensure a truer printed black and a faster drying time. Black ink is also less expensive than colored inks.

Why is it necessary to use a viewing booth for comparing colors?

To provide a neutral standard viewing area that eliminates external variables.

primary subtractive colors

cyan, magenta, yellow

A diffraction ________ is used to separate colors in light.

grating

A beam of light coming toward a surface is called the _____ beam.

incident

To what does the term brightness refer?

refers to lightness or luminosity and can be defined as a value indicating how light or dark a color is.

Our eyes are only sensitive to a small part of the electromagnetic spectrum. What is this range called?

visible light or visible spectrum