Abstract: A method and an apparatus for measuring color of a moving web. The web is measured by reflectance measurement and transmittance measurement, wherein the reflectance measurement is carried out by illuminating a surface of the web in a measuring area, where on the other side of the web at the measuring area resides a solidly attached backing element and measuring the radiation reflected from the web. The transmittance measurement is carried out by illuminating the web and measuring the radiation transmitted through the web. The radiation measured in the transmittance measurement is transmitted through the backing element.

Abstract: A method and an apparatus for measuring color of a moving web. The web is measured by reflectance measurement and transmittance measurement, wherein the reflectance measurement is carried out by illuminating a surface of the web in a measuring area, where on the other side of the web at the measuring area resides a solidly attached backing element and measuring the radiation reflected from the web. The transmittance measurement is carried out by illuminating the web and measuring the radiation transmitted through the web. The radiation measured in the transmittance measurement is transmitted through the backing element.

Abstract: Devices, systems, and methods for measuring the color of a sample are disclosed. The exemplary device may have one or more light emitting diodes for directing a beam of ultraviolet light onto the sample and may also have one or more light emitting diodes for directing a beam of visible light onto the sample. The exemplary device may have a component for controlling the timing and power of operation of each light emitting diode. The exemplary device may also have at least one light detector for receiving the beam of light reflected from or transmitted through the sample and measuring at least one wavelength band of the received light. The exemplary device may further have a measurement analyzer for determining the color of the sample based on the measured light. The color may be determined for a specified illuminator incorporating effects of fluorescence.

Abstract: An apparatus includes at least one scanner. Each scanner includes a plurality of sensors, and each sensor is capable of measuring one or more characteristics associated with a portion of a substrate. The substrate has printing produced by a printing system. The apparatus also includes a controller capable of receiving at least some of the measurements from the plurality of sensors and determining a quality of the printing on the substrate using the received measurements. The substrate could represent paper, and the printing system could represent an offset printing system. At least one of the sensors may be in a fixed position and/or at least one of the sensors may be movable over part of a surface of the substrate. The determined quality of the printing could involve density, dot area, dot gain, contour sharpness, doubling, mottling, ghosting, misregister of different colored inks, slur, or improper positioning of the printing.

Abstract: A method includes generating at least one first light beam and generating at least one second light beam and at least one third light beam using the at least one first light beam. The at least one first light beam has a plurality of first regions, the at least one second light beam has a plurality of second regions, and the at least one third light beam has a plurality of third regions. Each of the first, second, and third light beams has at least two regions that are spectrally different. The method also includes measuring a spectrum in each of a plurality of first wavelength bands for each of the second regions. The method further includes illuminating at least part of an object with the at least one third light beam to produce at least one fourth light beam. The at least one fourth light beam has a plurality of fourth regions, where at least two of the fourth regions are spectrally different.

Abstract: The invention relates to a method and arrangement for measuring optical properties from paper or board that constitutes a target to be measured and comprises two planar surfaces. In the arrangement, one surface of the target to be measured is illuminated by an optical power source, and the illuminated area on the opposite side of the illuminated surface comprises at least one backing with known optical properties. A detector detects the illuminated surface in the area of the backing, and at least one optical property of the target to be measured is determined by means of spectral information obtained at the backing.

Abstract: The invention relates to a method and arrangement for measuring optical properties from paper or board that constitutes a target to be measured and comprises two planar surfaces. In the arrangement, one surface of the target to be measured is illuminated by an optical power source, and the illuminated area on the opposite side of the illuminated surface comprises at least one backing with known optical properties. A detector detects the illuminated surface in the area of the backing, and at least one optical property of the target to be measured is determined by means of spectral information obtained at the backing.

Abstract: The invention relates to a method and an apparatus according to the method. A sample is illuminated by a band of optical radiation the illumination state of which is variable as a function of time. Reference measurements of the spectrum of the optical band illuminating the sample are made at least at three separate instants of time. A spectrum of a band of the optical radiation that has interacted with the sample is measured at the corresponding separate instants of time as the reference measurement, and the radiance transfer factor matrix of the sample is estimated from the set of reference measurements and the set of sample measurements.

Abstract: The invention relates to a method and an apparatus for controlling a coloring process. In the coloring process, at least one fluorescent or non-fluorescent ingredient is added and the color of the substrate is determined by using a coloring model which describes the effect of said ingredient on the radiance transfer factor for the substrate to be colored.

Abstract: The invention relates to a method and apparatus for determining the color and/or composition of a material. A sample of the material is illuminated with at least three separate illumination bands singly or in combination, said illumination bands collectively substantially spanning at least the visible range. The light reflected or transmitted by the sample is measured with at least four light detector elements responsive to light in wavelength bands which substantially span the visible range when the sample is illuminated. The width of the illumination bands differs in such a manner that the illumination bands are narrowest near the expected fluorescence absorption bands.

Abstract: The invention relates to a method and apparatus for determining the color and/or composition of a material. A sample of the material is illuminated with at least three illumination bands singly or in combination, said illumination bands collectively substantially spanning at least the visible range. The light reflected or transmitted by the sample is measured with at least four light detector elements responsive to light in wavelength bands which substantially span the visible range when the sample is illuminated. The measured reflected or transmitted light is compared to the light reflected or transmitted by a reference material of known apparent emissivity or transmissivity and the apparent emissivity or transmissivity of the sample is calculated therefrom.

Abstract: The invention relates to a method and apparatus for measuring and controlling optical properties of a moving web. Sensor heads are installed in the same location on the opposite sides of the web to be measured so that there is at least one means of illuminating the web and at least one means of detecting radiances on both sides of the web. At least one means of illuminating the web of at least one side is controlled so as to provide at least two different lighting states. Measuring the values in different lighting states with both means of detecting radiances simultaneously allows determination the optical properties of the web on its both sides.