Characterizing Color with Reflectance

Sattar, Simeen

doi:10.1021/acs.jchemed.8b00845

Cited by 25 publications

(27 citation statements)

References 14 publications

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“…The lightness coordinate varies between 0 and 100, where zero is black and 100 is white. The contours vary from -a*b* to + a*b*, where a negative a* corresponds to green and positive to red tones, and the negative b* corresponds to blue and the positive corresponds to yellow tones [55]. The CIELAB parameters also allow the calculation of colour differences [56][57][58].…”

Section: Methodsmentioning

confidence: 99%

“…Regarding black colour, a* and b* coordinates are expected to be around zero and not presenting a large difference between them (achromatic aspect) [55]. Figure 3 presents the chroma coordinates of the analysed specimens in M0, M12, and M24, considering the specimens with and without (standard) NIR reflective pigments (with and without primer application).…”

Section: Colourmentioning

confidence: 99%

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Impact of Incorporating NIR Reflective Pigments in Finishing Coatings of ETICS

et al. 2021

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Near-infrared (NIR) reflective materials are being developed for mitigating building cooling needs. Their use contributes to broadening the range of colours, responding to the urban aesthetic demand without compromising the building performance. Despite the increase in NIR reflective pigments investigation, there is still a knowledge gap in their applicability, impact, and durability in multilayer finishing coatings of External Thermal Insulation Composite Systems (ETICS). Hence, the main goal of this work consists of evaluating the impact of incorporating NIR reflective pigments (NRP) in the solar reflectance of the surface layer of ETICS, without affecting the colour perception, as well as their influence on the colour durability and surface temperature. As such, colour, solar reflectance, and surface temperature were monitored for 2 years in dark-coloured specimens of ETICS, with and without NRP and a primer layer. It was confirmed that the main contribution of NRP is the increase of solar reflectance and, consequently, the decrease in surface temperature, especially for high exterior temperatures (around 30 ºC). Moreover, these pigments highly increase the NIR reflectance without affecting the visible colour. In addition, they contribute to maintaining the colour characteristics. The application of primer increased the surface temperature, especially for higher exterior temperatures. However, it contributes to a lower colour difference and solar reflectance variation, which is an important achievement for durability purposes.

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Section: Methodsmentioning

confidence: 99%

Section: Colourmentioning

confidence: 99%

Impact of Incorporating NIR Reflective Pigments in Finishing Coatings of ETICS

et al. 2021

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“…The lightness coordinate varies between 0 and 100, where zero is black, and 100 is white. The contours, vary of -a * b * to + a * b * , where a negative a * corresponds to a green and positive red tones, and the b * negative blue and the positive yellow tones [15]. There is general agreement that using the CIELab system is an improvement over using the Euclidean distance between XYZ tristimulus coordinates as a colour difference metric.…”

Section: Cielab Systemmentioning

confidence: 99%

“…Chroma variation, for the red colour, is related to the reflectance variation in the visible spectrum. In this case, the thermal behaviour of the cool nanopigment may have been affected, since some light colours, as orange and yellow, can reflect more light in the visible spectrum, as analysed by Sattar [15].…”

Section: Influence Of Nanopigmentsmentioning

confidence: 99%

Colour degradation of façade coatings – the effect of nanopigments incorporation

et al. 2020

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The increasing interest in the use of a wide range of colours in buildings, especially dark colours, may lead to the early degradation of the façades, compromising their aesthetic and thermal performance. On the other hand, the incorporation of nanopigments with high reflectance properties can contribute to reducing the absorption of solar radiation. The nanoparticles contribute to increasing the solar reflectance of coatings, decreasing the surface temperature and improving the coating performance. This work evaluates the natural degradation of the colour of finishing coat with nanopigments in ETICS. The colour parameters were evaluated in different ETICS specimens, considering the colour black and red with and without incorporated nanopigments, under natural ageing. The colour measurement was performed according to ISO 1164-4, using a portable spectrophotometer. The results confirmed that the use of nanopigments improved the colour durability, promoting the maintenance of the colours parameters. The total colour difference was lower than the perceptible by the human eyes, even as the lower variation on chroma and hue parameters of the colours with nanopigments. In summary, the incorporation of nanoparticles in finishing coat of ETICS can contribute to increasing their durability and improve their thermal performance without compromising the aesthetic characteristics.

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“…It is suitable for application to a wide range of imaging and sample analysis tasks. Many undergraduate and postgraduate courses include the topics of spectroscopy, − chemometrics, − and colorimetry. , The multispectral imager (MSI) described here could be a useful teaching aid for many of these courses. At an introductory level, it provides an intuitive and hands-on way for students to understand the basics of spectroscopy, while at a more advanced level it provides opportunities for students to develop skills in the essential chemometric multivariate analysis techniques of principal component analysis and k-means clustering.…”

Section: Introductionmentioning

confidence: 99%

Low-Cost Multispectral Imager

2020

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A low-cost multispectral imager was built using a multiwavelength LED PCB (light-emitting diode printed circuit board), 3D printed housing, and a monochrome camera, and it was controlled via National Instruments LabVIEW software coupled with some simple electronics. Multivariate data analysis was performed using freely available software packages. The device is sufficiently simple in its construction and operation to be of use in many undergraduate courses concerned with topics such as spectroscopy, chemometrics, and colorimetry.

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Characterizing Color with Reflectance

Cited by 25 publications

References 14 publications

Impact of Incorporating NIR Reflective Pigments in Finishing Coatings of ETICS

Impact of Incorporating NIR Reflective Pigments in Finishing Coatings of ETICS

Colour degradation of façade coatings – the effect of nanopigments incorporation

Low-Cost Multispectral Imager

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