Explain subtractive theory or pigment theory based on spectrophotometer (data color), X drive, Bedo-tree point, X plonger.

Experiment No: 05

Experiment Name: Explain subtraction theory or pigment theory based on spectrophotometer (data color), X drive, Bedo-tree point, X plonger.

A color measurement spectrometer measures the reflectance.

Reflectance =(Reflactance light)/(Incident light)×100%

Generally reflectance is expressed as percentage. Color measurement spectrophotometer follows the sample theory of color vision. A light source is used to illumination and viewing geometric reflected or transmitted light is then passed on the spectral analyzer. Where the light is spilt into the spectral component. Then the light detector and control electronics to make measurement across the visible spectrometer. We used pulse xenon lamp for specific illumination. It is approximately to illuminate 

D_65-

Figure:

Figure: Schematic diagram of reflection spectrophotometer with an integration sphere.

Object of spectrophotometer:

(1) Recipe develop from standard sample.

(2) Recipe calculation to exact shade.

(3) Check CIE.

The angles and method by which a sample is illuminated and viewed can affect the observer dramatically. The geometric of a color measured instrument is therefore and important factor is its design. There are 3 common instruments geometrics:

(1) Illuminations of the sample at an angle of 45⁰ to its surface and detection of the reflected light at close to right angles (45/0 geometry).

(2) The reverse of the (0/45 geometry).

(3) Difference illuminations of the sample from all direction using and integrating sphere and detection of reflected light at closed to perpendicular to the sample (d/0 or more often d/8 geometry).

Figure: