human eye can distinguish how many different colors
about 10 million different colors within the visible light
human vision is what?
trichromatic color vision
color vision defined by?
constructed by the VISUAL BRAIN – and NOT the property of objects
RGB color model
additive color model mixing with primary colors of red, green, and blue
CMYK color model
subtraction color model. used in color printing. combining cyan, magenta, and yellow transparent dyes/inks on white substrate.
black is added as fourth
Albert Munsell
inventor of color system
tooth color is seen in what color range
yellow and brown range
chroma defiens
color intensity or strength
like light blue to deep blue
value of E that will determine a noticeably different color change
2.3
Inadequacies of shade guide
- color range does not cover the entire color of natural tooth
- tabs are not evenly arranged in the color solid; color between neighboring tabs is unequal
- lack of consistency among various shade guides, different companies use different shade standards, slightly different but still significant
- poor match between shade tabs and their corresponding commposite shades
- light cure may alter after composite color differences 3.7-12.0 unit
describe liquid and gas matter
what holds them together?
held together by hydrogen bond or can der waals forces
no confined dimension
easy to deform
definition of phase?
examples
phase is a region of space with essentially uniform physical property
- like crystalline (cubic zirconia, ice, most ceramics, metal)
- amorphous (wax, carbon black, glass)
multi-phasic materials
IPN (interpenetration network)
composite
main mineral in dental enamel
fluoridated carbonated- calcium deficient hydroxyapetite
- main mineral of which dental enamel and dentin are comprised
percent of water in mature enamel
less than 5
describe crystals in enamel
ribbon or needle like carbonated HAP nanocrystal
HIGHLY organized
What generates color
electromagnetic radiation (but we can only see a small fraction of this)
photon particle beam
characteristic colors are what? frequency range?
red, orange, yellow, green, cyan, blue, violet
from low to high frequency
general description of color vision
a QUALITY constructed by the visual brain and NOT property of the objects.
the nervous system derives color by comparing the responses to light from the several types of cone photoreceptors in the eye
what do differences in frequency do?
gives rise to a difference in perceieved hue
noticeable differences in the wavelengths occurs where?
varies from about 1nm in the blue-green and yellow to about 10 nm and more in the red and blue
describe color reproduction and why important?
- need to have man-made color production a camera can see, a printer can print, or a monitor can display
- edit images in a controlled, consistent manner
- need parameters to control the color reproducibility
- need coordination to express the color differences
hue
dominant color of wavelength detected
chroma
color intesnity ot strength
