What is Kubelka-Munk method?
The Kubelka–Munk theory is used in papermaking in several ways. If one knows the optical properties of each pulp, filler, and dye used in papermaking, then the optical properties of a paper made with any combination of the materials can be predicted.
What is Kubelka-Munk units?
Kubelka-Munk (K-M) theory is a phenomenological light transport theory that provides analytical expressions for reflectance and transmittance of diffusive substrates such as tissues. Many authors have derived relations between coefficients of K-M theory and that of the more fundamental radiative transfer equations.
When to use Kubelka-Munk?
The Kubelka–Munk theory is also used in the paper industry to predict optical properties of paper, avoiding a labor-intensive trial-and-error work approach.
How do you convert reflectance to absorbance?
Spectral Absorbance (A) was calculated as: Absorbance = 1- (Reflectance + Transmittance).
What is Kubelka Munk plot?
The Kubelka-Munk (K-M) model has a particularly simple solution in the case of semi-infinite samples. All the geometric peculiarities of the inhomogeneous sample are condensed into a single parameter, the scattering coefficient s. In reality, the scattering coefficient does vary slowly with wavelength.
How is band gap calculated from UV Vis reflectance spectra?
From UV-Vis spectrum, you are able to calculate the band gaps of material (allowed direct, allowed indirect, forbidden direct, and forbidden indirect transitions), by plotting the graph between (ahv)^(1/n) versus photon energy (hv).
What is the principle of reflectance spectrophotometry?
Diffuse reflectance spectroscopy is a well-established technique for studying the spectral characteristics of opaque solid samples, based on the principle that not only does light reflected from the material come from the surface (specular reflection) but some is reflected internally (diffuse reflectance).
How do you calculate how much light is reflected?
The law of reflection states that the angle of reflection equals the angle of incidence—θr = θi. The angles are measured relative to the perpendicular to the surface at the point where the ray strikes the surface.
How do you calculate light reflectance value?
This contrast is calculated using the following formula: (B1 – B2) x 100 / B1, where B1 and B2 are the LRV of the lighter area and darker area, respectively. The LRV can be obtained using the CIE Y values measured under the illuminant D65 (natural daylight) and 10° observer.
What is the Kubelka-Munk theory?
The Kubelka-Munk theory, devised by Paul Kubelka and Franz Munk, is a fundamental approach to modeling the appearance of paint films.
What is the Kubelka-Munk model of diffuse reflection?
Continuous models are widely used to model diffuse reflection from particulate samples. They are embodied in various theories, including diffusion theory, the equation of radiation transfer, as well as Kubelka-Munk. In spite of its widespread use, there has long been an understanding that the Kubelka–Munk (K–M) theory has limitations.
What is a Kubelka-Munk conversion for FTIR?
A Kubelka-Munk conversion can be applied to a diffuse reflectance spectrum to compensate for these differences. This conversion is available in most FTIR software packages. The Kubelka-Munk equation is expressed as where Ris the absolute reflectance of the sampled layer, kis the molar absorption coefficient and sis the scattering coefficient.
What is the Kubelka-Munk equation for ibuprofen?
The Kubelka-Munk equation is expressed as where R is the absolute reflectance of the sampled layer, k is the molar absorption coefficient and s is the scattering coefficient. The spectra shown above demonstrate this spectral conversion for ibuprofen collected by diffuse reflectance.