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Used IR Spectrometers and others type

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You can find used IR Spectrometers and others type on Wotol

The main manufacturers of IR Spectrometers and others type are Perkin Elmer, Thermo Nicolet, Jasco, Foss, Nicolet, Bruker, Shimadzu, Thermo Electron, Varian, Agilent, Thermo, Alere, Magna.

Find the right Spectrophotometer or Instrumental color measurement with our expert
This instrument has lens, light source, difraction gratting or prism and color analyser.
What is "Color" ? When we see the object and then we say the color is Blue , do you know why ?
It is because object reflected Blue color and adsorb other color. To see colors we need: Object, illuminant (light source), observer (Eyes or Lens) and then Brain or Analyser will calculate so we have "Color"
Our eyes always see what refelected by object. Similar case with Spectrophotometer it can measure reflectance and transmitance.
The next step would be the physical measurement of  the
object, for reflected (or transmitted) light, by a color spectrophotometer.  The basic information provide by  the “spectro” is simply the wavelength reflectance values across the visible spectrum, known as spectral data, which can be displayed as a spectral curve.

Now 2 of the 3 elements  of the observer situation are represented as numbers.
Spectral reflectance data
- Spectral measurement range:
  380nm to 730nm
- Reflectance range
  "Normal" samples: 0% to 100%
  (100% = perfect white diffusor  0% = perfect black)
  Effect samples: up to 300% (for small aspecular angles)
  Fluorescent colors: up to 200%

Color identification
Spectral information under defined geometrical conditions is the fingerprint of a color
The spectral information can be transformed so that colors can be arranged in a 3 - dimensional color space
Every color has a unique "address" color space
The "address" is valid for a certain illuminant (D65 or A or TL84 or others) and  for a certain observer (2° or 10°) and for a certain geometry (d/8°, 45°/0° or others) !
Changing illuminant and/or observer and/or geometry in most cases will result in a different "address" in color space for the same sample
Color order system, color space
CIE L*a*b*   1976
Based on the Munsell system
L* a* b* are the primary coordinates
L*:   Lightness direction
a*:   red - green direction
b*:   yellow - blue direction
CIE Lab system is industry standard

CIE Lab system version 2
C*, h: Same facts, different description
polar coordinates instead of kartesian coordinates
Chroma     (independent of hue)
C*= (a*2 + b*2) 1/2
Hue angle (independent of chroma)
h= arctan (b* / a*) counterclockwise, starting at positive a* axis with h = 0°

Color difference description
Most important for industrial use
Color difference is the distance in color space between two adresses", e.g. between the "adress" of a standard and the "adress" of a trial.
The color difference has 3 components:
Lightness difference     dL*=L*trial - L*standard
red-green difference     da*=a*trial - a*standard
yellow-blue difference   db*=b*trial - b*standard

Total color difference dE* is calculated from the 3 components:
dE*= (dL*2 + da*2 + db*2) 1/2
Same facts, different description
dE*= (dL*2 + dC*2 + dH*2) 1/2
Chroma difference     dC* = C*trial - C*standard
Hue difference   dH*= (da*2 + db*2 - dC*2) 1/2
sign dH*: positive if
a*trial  b*standard - a*standard b*trial R0 else negative.

Attention: dH* is a distance in color space and not the difference of the hue angles htrial - hstandard !!!
But the computer has no problem with the slightly complicated calculation

Common brand:
Datacolor, GretagMacbeth, Hunterlab, Kurabo, Macbeth, Minolta and Xrite

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