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Colorimetric practice. Colour measuring instruments Lightsource colorimetry Luminance and brightness description Measurement of materials: colour recipe, fluorescence, signal colours. Instruments. Tristimulus colorimeters Spectroradiometers scanning, band-width and sampling
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Colorimetric practice • Colour measuring instruments • Lightsource colorimetry • Luminance and brightness description • Measurement of materials: colour recipe, fluorescence, signal colours
Instruments • Tristimulus colorimeters • Spectroradiometers • scanning, band-width and sampling • CCD type, missed details • Image forming colorimeters
Tristimulus colorimeter • Luminace and illuminance measuring
Tristimulus filters • Sandwich type filters • Partial filtering
Goodness of fit evaluation • Spectral mismatch error description
Spectral match of a full-filtered instrument F1x=2.6, F1y=2.2, f1z=3.8
Angular responsivity • Illuminace type: • cosine corrected • Luminance type: • narrow beam measurement: • 0.5 ° … 2°opening angle • Image forming colorimeter • problem with contrast, induction and assimilation
Colour correction of a CCD colorimeter • F1x=7.5, f1y=3.6, f1z=3.9
Spectroradiometry • Optics of the equipment • Bandwidth • Stray light • Single and double monochromators • Detection • photomultipliers • CCD arrays
Spectroradiometry • Spectral irradiance measurement • Spectral radiance and flux measurement • The spectroradiometer • Measurement principles • Practical measurements
Monochromators - 1 • Light grasp or etendu, throughput, efficiency: • Double monochromator: • Two gratings (additive, subtractive dispersion) • grating + prism
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°
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
Method of measurement • Sequence: test - standard • Transmittance function - Bandwidth
Grating monochromator • Second order specrum, cutting by filters or a prisn pre-disperser
CCD type detector systems • Single grating • stray light • second order • Detector system • Pixel area – inter pixel area • linearity • dynamic range
Practical measurements - Errors • Stray light • Wavelength error • Bandwidth - interpolation, extrapolation • Polarization • Detector system • Reference standard