Multi‐wavelength excitation method for measuring FWA‐treated paper

Imura, Kenji; Nagai, Yoshiroh

doi:10.1002/col.22166

Cited by 3 publications

(11 citation statements)

References 4 publications

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“…However, this effect of the ink layers on the paper reduces the overall fluorescence. The net effect on the impact to interinstrument measurement reproducibility in the MWE method is not expected to be very significant …”

Section: Resultsmentioning

confidence: 99%

“…From the principle described above, the reproducibility of the MWE method depends on both the SPDs I k (μ) and the weights W k in Equation (6). Since W k are optimized based on I k (μ) and the typical bispectral luminescent radiance factors B L,t (μ, λ), which is invariant among instruments once provided as the common numerical data, the variation of I k (μ) is likely to give major impacts to the reproducibility.…”

Section: Objective Of This Studymentioning

confidence: 99%

“…6 ORCID Kenji Imura https://orcid.org/0000-0002-9767-3281 However, this effect of the ink layers on the paper reduces the overall fluorescence.…”

Section: Remarksmentioning

confidence: 99%

“…Its variation directly impacts reproducibility (interinstrument or intermodel agreement), which is an essential requirement in many cases where data compatibility among instruments from different manufacturers is required. The multiwavelength excitation (MWE) method was developed to measure fluorescent whitening agent (FWA)‐treated specimens illuminated by I D without an illumination close to I D. …”

Section: Introductionmentioning

confidence: 99%

“… 3.The luminescent SPDs E L ( I k , λ ) in the overlapping range (400‐430 nm for most FWAs) excited by I k in the range, which are unmeasurable due to the overlap of luminescence and reflection, are estimated as described in the previous article …”

Section: Introductionmentioning

confidence: 99%

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Impacts of spectral variations in multiwavelength excitation method on measurements of fluorescently whitened papers

Imura

2019

Color Research & Application

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The multiwavelength excitation (MWE) method for measuring the colorimetric properties of fluorescent whitening agent (FWA)-treated specimens illuminated by a standard daylight illuminant computationally approximates not the spectral power distribution (SPD) of the illuminant but the luminescent SPD excited thereby by a weighted sum of the luminescent SPDs excited by a few different narrow-band illuminations. The weights are optimized for the actual SPDs of those illuminations and the bispectral luminescent radiance factors of typical FWA-treated paper specimens. Since the latter is invariant among instruments once provided as the common numerical data, the variations of the narrow-band SPDs give major impacts to the reproducibility of this method.The weights optimized for the varied SPDs, however, mitigate the impacts. For investigating how they impact, one basic illumination system and its 16 simple variation systems were built virtually. The basic system consists of three narrow-band LEDs and one blue-excited white LED, whereas the individual simple variation system has either the peak wavelength or spectral width of one of the four LEDs (including the blue LED in the white LED) varied. With those systems, seven FWA-treated papers with the known bispectral radiance factors were measured computationally by simulating the procedure of the MWE method. The differences in the colorimetric values measured with the simple variation systems from those with the basic system are far below the just noticeable difference, which indicates that the MWE method can be a practical solution for better reproducibility in measuring FWA-treated papers. K E Y W O R D SFWA-treated paper, MWE method, narrow band LED, reproducibility

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Section: Resultsmentioning

confidence: 99%

Section: Objective Of This Studymentioning

confidence: 99%

“…6 ORCID Kenji Imura https://orcid.org/0000-0002-9767-3281 However, this effect of the ink layers on the paper reduces the overall fluorescence.…”

Section: Remarksmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impacts of spectral variations in multiwavelength excitation method on measurements of fluorescently whitened papers

Imura

2019

Color Research & Application

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New method of whiteness calibration of spectrophotometers

Brill¹,

Xu²

2023

Color Research & Application

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A method is described for determining and calibrating the CIE Whiteness Index (WI) of an OBA‐treated specimen without incorporating into the measurement system a mechanically adjustable UV filter. The method requires spectrophotometric measurement of the specimen under two lights: UV‐excluded to infer the reflectance r(λ) and UV to infer the fluorescence profile f(λ). Also required is a stored illuminant spectrum Iin(λ) that covers at least the whole visible wavelengths. Only one scalar value k is then needed to mathematically characterize the total spectral radiance factor (TSRF) of the same specimen under Iin(λ). Calibration uses a reference specimen with known WI, and adjusts k until the computed WI matches the reference WI value. If Iin(λ) is the illuminant chosen from ASTM E313 to define the WI, the k adjustment reduces to solving a single quadratic equation for k that involves the reference WI. In general, relative to directly measuring a specimen's TSRF, it is more instrument‐independent to use the current method to characterize TSRF. Therefore, if a fluorescent specimen is measured using UV and UV‐excluded illuminants, a complete, instrument‐stable characterization of the specimen's TSRF can be derived by adjusting k, which can be done through a closed‐form relation of k to the WI.

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Paper-Based Low Cost Optical Filter

Tripathi¹,

Rawat²,

Tiwari

2020

Preprint

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<p>We report simple and inexpensive technique using several sheets of white paper for filtering the blue and non-blue radiation of a white light emitting diode source in the transmission mode. We visibly illustrate successful rejection of specific energy of white light by the filtering papers through absorption mechanism where weak transmission of blue and red radiations are observed. In addition, photoluminescence arising from the papers in near infrared region is also presented while using the white light excitation. Owing to the presence of different whitening agents in the papers, selective absorption and divergent coloured emission from the sheets are observed.</p>

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Multi‐wavelength excitation method for measuring FWA‐treated paper

Cited by 3 publications

References 4 publications

Impacts of spectral variations in multiwavelength excitation method on measurements of fluorescently whitened papers

Impacts of spectral variations in multiwavelength excitation method on measurements of fluorescently whitened papers

New method of whiteness calibration of spectrophotometers

Paper-Based Low Cost Optical Filter

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