15. E Flashcards
The __ of an object is determined by the light that enters the human eye. Color that is perceived is the result of a ____, the object that absorbs, transmits, reflects or scatters the light from the source, and the interpretation of the source and the result by the human visual system
color, light source
is a form of visible energy that is part of the radiant energy spectrum.
Light
_____ possesses specific wavelengths, which may be used to identify the type of energy
Radiant energy
can be described by three dimensions of physical form (length, width, and depth)
COLOR
three large bands of color (red, green, and blue) are observed in the visible light spectrum
COLOR MIXING
three large bands of color?
red, green, and blue
→ these are the primary colors of the spectrum; combine them to make all other spectral of colors
COLOR MIXING
→ efforts are being made to standardize terminology in order to ensure accuracy with regard to color language, with magenta, cyan, and yellow, using the correct names for the subtractive primary colors
COLOR MIXING
widely used in the dental literature and also used in the past to quantify color
MUNSELL COLOR ORDER SYSTEM
→ a popular method of visually describing color
→ the three attributes of color in this system are called hue,
chroma, and value
MUNSELL COLOR ORDER SYSTEM
described by Munsell as “that quality by which we distinguish one color family from another, as red from yellow, or green from blue or purple … it is the family name we apply to a group of colors”
HUE
a particular variety of a color
o the shorter the wavelength, the closer the hue is to the violet
portion of the spectrum
o the longer the wavelength, the closer it is to the red portion
HUE
True or false
there are ten hue families in the Munsell Color Order System
True
stated by Munsell as “that quality by which we distinguish a light color from a dark one”
VALUE
the relative lightness or darkness of a color or the brightness of an object
VALUE
the possible range of values used in describing the lightness or darkness of a surface in the Munsell Color System extends from zero to ten
VALUE
black is zero and white is ten with a range of grays between these end points of the scale
VALUE
that quality of color by which we distinguish a strong color from a weak one
CHROMA
the degree of departure of a color sensation from that of white or gray
CHROMA
*the intensity of a distinctive hue
*color intensity
CHROMA
used almost exclusively for color research in dentistry around the world
CIELAB COLOR SYSTEM
easy to interpret clinically, as equal distances across the CIELAB color space
CIELAB COLOR SYSTEM
represent approximately uniform steps in human color perception, which improves the interpretation of color measurement
CIELAB COLOR SYSTEM
the lightness variable proportional to value in the Munsell system
L*
describes the achromatic character of the color
L*
describes the chromatic characteristics of the color
a AND b*
the process in which the color of adjacent teeth is replicated in metal-ceramic or all-ceramic crown
COLOR REPLICATION PROCESS
this phase occurs in the dentist’s office, in which the information on the color and translucency of the adjacent tooth to be matched is recorded through either visual shade matching or instrumental color analysis
SHADE MATCHING PHASE
_____ was the first to accurately describe the color of teeth
Clark
→ these samples are compared with the natural teeth and the
closest color match is determined
→ anterior teeth may vary from posterior teeth
DENTAL SHADE GUIDES
the rods and cones of the retina form the chief component of the retinal receptor complex
RESTRICTING LIGHT
the rods detect only lightness and darkness, the achromatic aspects of an object (value)
RESTRICTING LIGHT
the cones perceive the chromatic aspects of an object (hue and
chroma)
RESTRICTING LIGHT
the cones predominate at the center of the retina, zone behind
the lens is macula lutea; wherein, a depression called fovea centralis is located, most of the cones are located
RESTRICTING LIGHT
→ when light strikes an object, some wavelengths are absorbed by the object and some are reflected
→ what is commonly called “the color of an object” is actually the color of light that has been reflected
SURROUNDING COLORS
→ in the dental operating room, light strikes a variety of objects in the surrounding environment and is reflected
→ even if there is a good light source present, the light can be altered into an unacceptable form by the time it reaches the mouth in which actual shade selection is being performed
SURROUNDING COLORS
the color selection process should be performed when sufficient time can be devoted to identify the best color match
TIME OF SELECTION
good procedure involves selecting the shade at the diagnostic appointment
TIME OF SELECTION
→ having the patient seated upright and at the observer’s eye level, thus, becomes the most beneficial position for clinical shade selection
PATIENT POSITION
moist teeth is best during shade selection
TOOTH CONDITION
a selection is made at 3-6 feet from the oral cavity since it is representative of the conditions under which the patient’s teeth will most often be observed
SELECTION DISTANCE
not accurate representations of clinical color but can be useful in showing the laboratory technician the extent of translucency and the magnitude and location of surface characteristics
PHOTOGRAPH
the matching of apparent color of objects with different spectral power distributions
METAMERISM
another way of saying it is when objects of different material or composition look the same under one light source but different under another
→ this is the challenge of shade matching
METAMERISM
