Threshold and suprathreshold perceptual color differences

Witzel, R. F.; Burnham, R. W.; Onley, Judith Wheeler

doi:10.1364/josa.63.000615

Cited by 94 publications

(49 citation statements)

References 14 publications

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“…Chromatic variations have been calculated to assess the difference in colour between treated and untreated samples, in accordance with [22]. Results about colorimetric tests suggest that the colour change (ΔE) is generally around 3-4 for all products and can be considered acceptable [38].…”

Section: Colorimetric Tests (Ct)mentioning

confidence: 99%

The CRATI Project: New Insights on the Consolidation of Salt Weathered Stone and the Case Study of San Domenico Church in Cosenza (South Calabria, Italy)

et al. 2019

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This paper presents the results of a laboratory experimentation carried out on stone materials in the framework of the CRATI project (Knowledge and Restoration through Advanced Integrated Technologies) aimed at testing new products with consolidating properties by means of an integrated methodological approach. After the preliminary characterization of stone materials collected in the pilot site, the second stage of the activities within the project were focused on the formulation and testing of products for the conservation of the same materials against decay, especially salt crystallization, one of the most aggressive and common degrading processes. The San Domenico Church, located in the old town of Cosenza (Calabria, Southern Italy) has been chosen as the pilot site and for the in situ tests. Several specimens with the same features of the stone materials used in San Domenico church were collected from a historical quarry near the city of Cosenza. These specimens were treated and then artificially degraded by salt crystallization tests in order to evaluate their susceptibility to weathering intensity. Three different consolidating products were used; respectively, two commercial and another one formulated in laboratory: (a) a suspension of nanosilica (Nano Estel®); (b) a suspension of nanolime (CaLoSiL®), and (c) a suspension of nano calcium-hydroxide dispersed in isopropyl alcohol and then mixed with diammonium hydrogen phosphate. A systematic approach, including minero-petrographic, geochemical and physico-mechanical techniques, was applied to evaluate (a) the nature and main features of materials; (b) the efficacy of consolidating treatments, and (c) the resistance of treated stone to the salt crystallization processes. The tested products demonstrated a significant efficiency to consolidate and protect stone material samples, enhancing their resistance to salt crystallization. Thus, such a case history may be useful in order to plan appropriate restoration interventions that consider the interactions between the building stone and the protective/consolidating product.

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Section: Colorimetric Tests (Ct)mentioning

confidence: 99%

The CRATI Project: New Insights on the Consolidation of Salt Weathered Stone and the Case Study of San Domenico Church in Cosenza (South Calabria, Italy)

et al. 2019

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“…To quantify color change, ∆E [39,41] (12) was used taking into account different values are reported in the literature to indicate the threshold of perceivable differences [40,42,43]. Considering the largest threshold (∆E > 5), the measured ∆E appears as perceivable by human eye in almost all cases, ranging from 1.5 for SP (minimal color difference) to above 30.0 (perceived as two different colors).…”

Section: Energy and Architectural Implicationsmentioning

confidence: 99%

Cool Marble Building Envelopes: The Effect of Aging on Energy Performance and Aesthetics

et al. 2016

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Marble envelopes represent a relatively common architectural solution used in variety of historic, modern and contemporary building facades. White marble envelopes have been shown to reduce solar heat gains, while improving indoor thermal comfort and energy efficiency in summer time. While marble is useful in this context, the urban atmosphere accelerates the degradation of marble elements. This leads to changes in optical characteristics, hence the aesthetics, and affects the energy efficiency benefits offered by white marble facades. These issues are investigated in order to predict the impact of degradation on energy performance and to the aesthetic value, such as change of color and luminosity. In this study, surface degradation of white marble is analyzed by means of accelerated weathering in the laboratory while examining changes to the optical characteristics of the materials. A dynamic simulation is carried out to assess the energy performance of a building as a case study.

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“…Based on the CIE L*a*b* color space, the human eye cannot detect a ∆E* of below 2.0 [14]. A very basic level of analysis would be to find the mean ∆E* of tested samples and, if the mean is lower than 2.0, consider the samples colorfast.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Color Reading of Wood-Staining Fungal Pigment Textile Dyes: An Alternative Method for Determining Colorfastness

Hinsch

Robinson

2016

Coatings

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Colorfastness to washing and crocking (color loss due to rubbing) are essential qualities for any dye/fabric combination that will be used for garments or upholstery. In this study, colorfastness to washing and crocking of fabrics dyed with wood-staining fungal pigments was compared to colorfastness of commercial dyes using an alternative mechanical testing method. Overall, wood-staining fungal pigments out performed commercial dyes for colorfastness to washing and wet and dry crocking. Xylindein was the most colorfast dye. Draconin red yielded inconsistent results, and the yellow pigment required a mordant to achieve any colorfastness. This study showed that the mechanical color reading method, along with statistical analysis, provided an objective, repeatable gauge of colorfastness, although visual inspection is also needed for practical purposes.

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Threshold and suprathreshold perceptual color differences

Cited by 94 publications

References 14 publications

The CRATI Project: New Insights on the Consolidation of Salt Weathered Stone and the Case Study of San Domenico Church in Cosenza (South Calabria, Italy)

The CRATI Project: New Insights on the Consolidation of Salt Weathered Stone and the Case Study of San Domenico Church in Cosenza (South Calabria, Italy)

Cool Marble Building Envelopes: The Effect of Aging on Energy Performance and Aesthetics

Mechanical Color Reading of Wood-Staining Fungal Pigment Textile Dyes: An Alternative Method for Determining Colorfastness

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