Colorimetric practice

1
Colorimetric practice

• Colour measuring instruments
• Lightsource colorimetry
• Luminance and brightness description
• Measurement of materials colour recipe,
  fluorescence, signal colours

2
Instruments

• Tristimulus colorimeters
• Spectroradiometers
• scanning, band-width and sampling
• CCD type, missed details
• Image forming colorimeters

3
Tristimulus colorimeter

• Luminace and illuminance measuring

4
Tristimulus filters

• Sandwich type filters
• Partial filtering

5
Goodness of fit evaluation

• Spectral mismatch error description

6
Spectral match of a full-filtered instrument
F1x2.6, F1y2.2, f1z3.8
7
Angular responsivity

• Illuminace type
• cosine corrected
• Luminance type
• narrow beam measurement
• 0.5 2opening angle
• Image forming colorimeter
• problem with contrast, induction and assimilation

8
Colour correction of a CCD colorimeter

• F1x7.5, f1y3.6, f1z3.9

9
Spectroradiometry

• Optics of the equipment
• Bandwidth
• Stray light
• Single and double monochromators
• Detection
• photomultipliers
• CCD arrays

10
Spectroradiometry

• Spectral irradiance measurement
• Spectral radiance and flux measurement
• The spectroradiometer
• Measurement principles
• Practical measurements

11
The spectroradiometer system
12
Input optical arrangement-1
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Input optical arrangement-2
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Monochromators - 1

• Light grasp or etendu, throughput, efficiency
• Double monochromator
• Two gratings (additive, subtractive dispersion)
• grating prism

15
Monochromators - 2

• Stray radiationDetermination with
• Interference filter
• Sharp cut-off filters
• Lasers
• Wavelength accuracy /- 0,1 nm
• stability
• temperature dependence 0,1 - 0,5 nm/C

16
Detector and measuring system

• Irradiation of detector - homogeneity
• Type of detector photomultiplier, Si-cell
• linearity (superposition)
• temperature dependence
• high voltage stability
• Standard sources
• Method of measurement

17
Method of measurement

• Sequence test - standard
• Transmittance function - Bandwidth

18
Bandwidth sampling
19
Continuous scan method
20
Grating monochromator

• Second order specrum, cutting by filters or a
  prisn pre-disperser

21
CCD type detector systems

• Single grating
• stray light
• second order
• Detector system
• Pixel area inter pixel area
• linearity
• dynamic range

22
CCD arrey spectrometer
23
Practical measurements - Errors

• Stray light
• Wavelength error
• Bandwidth - interpolation, extrapolation
• Polarization
• Detector system
• Reference standard