A lot of these "words" I have written are written by others from my notes I have taken on stuff. Thanks in another posting about the credit, but I'm a tech person and disserve perhaps some credit but always need to have friends ensure what I'm doing is correct in making it safe for all. Nobody is a engineer or god, we all have both shortfalls and inperfections. Choice you have is allowing them to stay as a short fall, choice your friends have is in allowing those shortfalls to remain un-challenged.
So here is more "words" in answering the question as others have written:
(Read, study and learn as much as you can because in the end and in some respects what you even sort of remember will be all that stands in the way of a vague concept's success.)
Almost none of this I have written more than some form of laymen's follow up to.
Color
Rendering = As a rule, artificial light should
enable the human eye to perceive colors correctly, as it would in natural
daylight. Obviously, this depends to some extent on the location and purpose for which light is required. The criterion here is the color
rendering property of a light source. This is expressed as a “general color
rendering index” (
CRI). The color
rendering index is a measure of the correspondence between the color of an object (its “selfluminous color”) and its appearance under a reference light source. To determine the
CRI values, eight test colors defined in accordance with DIN 6169 are illuminated with the reference light source and
the light source under test. The smaller the discrepance, the better the color
rendering property of the lamp tested. A light source with a
CRI value of 100 displays all colors exactly as they appear under the reference light source. The lower the
CRI value, the poorer the colors are rendered. - Osram Photo-Optic Lighting Products, 1999
Color Temperature = Originally, a term used to describe the “whiteness” of
incandescent lamp light.
Color temperature is directly related to the physical temperature of the
filament in
incandescent lamps so the Kelvin (absolute) temperature is used to describe
color temperature. For discharge lamps where no hot
filament is involved, the term “correlated
color temperature” is used to indicate that the light appears “as if” the discharge lamp is operating at a giving
color temperature. More recently, the term “chromaticity” has been used in place of
color temperature.
Chromacity is expressed either in Kelvins (K) or as “X” and “Y” coordinated on the CIE Standard Chrom-aticity Diagram. Although it may not seem sensible, a high
color temperature (K) describes a visually cooler, bluer light source. Typical color temperatures are 2,800°K (
incandescent), 3,000°K (
halogen), 4,100°K (cool white or sp41
fluorescent), and 5,000°K (daylight-simulating
fluorescent colors such as
Chroma 50 and SPX 50.
Unit of measurement: Kelvin (K) the
color temperature os a light source is defined in comparison with a “black body radiator” and plotted on what is known as the “Planckian curve.” The higher the temperature of this “black body radiator” the greater the blue component in the spectrum and the smaller the red component. An
incandescent lamp with a warm white light, for example, has a
color temperature of 2,700°K, whereas a
daylight has a
color temperature of 6,000°K. - Osram Photo-Optic Lighting Products, 1999
Light color = The light color of a lamp can be neatly defined in terms of
color temperature. There are three main categories here: warm<3,300°K, intermediate 3,300 to 5,000°K, and
daylight > 5,000°K. Despite having the same light color, lamps may have very different color
rendering properties owing to the spectral composition of the light. - Osram Photo-Optic Lighting Products, 1999
CRI = Color
Rendering Index - An international
system used to rate a lamp’s ability to render object colors. The higher the
CRI (based upon a 0-100 scale,) the better colors appear.
CRI ratings of various lamps may be compared, but a numerical comparison is only valid if the lamps are also rated for the same
chromacity. (see
Chromacity.)
CRI differences among lamps are not usually significant (visible to the eye) unless the difference is more than 3-5 points.
v = Volts - A measurement of the electromotive force in an electrical
circuit or device expressed in volts.
Voltage can be thought of as being analogous to the pressure in a waterline. The
effect of
voltage on a lamp will cause a significant change in lamp performance. For any particular lamp, light output varies by a factor of 3.6 times and life varies inversely by a factor of 12 times any percentage variation in supply. For every 1% change in supply
voltage light output will rise by 3.6% and lamp life will be reduced by 12%. This applies to both DC and
AC current. Most standard
line voltage lamps are offered at 130v. Since most
line voltage power is applied at 120volts, the result is a slight under voltaging of the
filament. The
effect of this is substantially enhanced lifehours, protection from
voltage spikes and energy cost savings.
Voltage and Light Output: The
effect of
voltage on the light output of a lamp is ±1%
voltage over the rated amount stamped on the lamp, gives 3.1/2% more light or Lumens output but decreases the life by 13% and vise a versa.
Do not operate quartz Projection lamps at over 110% of their design
voltage as rupture might occur. GE Projection, Ibid p.13
A 5% change in the
voltage applied to the lamp results in
-Halving or doubling the lamp life
-a 15% change in luminous flux
-an 8% change in
power
-a 3% change in
current
-a 2% change in
color temperature (0.4% change per1%
voltage.)
Osram Technology and Application
Tungsten halogen Low
Voltage Lamps Photo Optics, p21
There is more to know and other stuff I have in notes about the subject but this should be a good start. Pay especial attention to the effects of votage on
color temperature, you will not find a figure of it's effects elsewhere but it's a key factor.