2Colour changes and reactivity to SO of some cladding stones at the “Gran Teatre del Liceu” (Barcelona; Spain)

Grossi, Carlota M.; Esbert, R. M.; Alonso, Francisco; Valdeón, L.; Ordaz, Jorge; Díaz-Pache, Francisco

doi:10.1016/b978-044450517-0/50114-8

Cited by 4 publications

(4 citation statements)

References 1 publication

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“…A representative color and reduced error because of color variability was gained by using the dif- ferences between two successive cumulative averages of the parameters L*, a* and b*. 14,19 Three or four stone specimens were used for each test and the number of shots for specimen varied from 9 to 16.…”

Section: Methodsmentioning

confidence: 99%

“…The experiments reported here focused on SO 2 attack, blackening in urban environments and laser irradiation for stone cleaning. [14][15][16][17] Color has been quantitatively measured with a MINOLTA CR-200 colorimeter prior, during and after laboratory and onsite trials on different-colored carbonate stones: whitish, grayish, yellowish, pinkish, and reddish. The selected limestones were mostly monochromatic, uniform in color, and did not exhibit notable surface color variation.…”

Section: Methodsmentioning

confidence: 99%

“…The parameter L* usually shows a decrease, whereas a* exhibited only significant changes in some cases, generally an increase 14,15 FIG. 4.…”

Section: Sulfur Dioxide Attackmentioning

confidence: 96%

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Color changes in architectural limestones from pollution and cleaning

Grossi

Brimblecombe

Esbert

et al. 2007

Color Research & Application

124

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This article investigates the impact of sulfur dioxide attack, deposition of dark particles in urban environments and laser cleaning with Nd:YAG 1064 nm on color change in a range of ornamental limestones. We have used the CIELAB and CIELCH systems to compare the relative importance of the variation of each coordinate for the color change. Sulfur dioxide and dark particle deposition seems to increase the chroma, most particularly in the yellow component. Particle deposition also leads to an obvious darkening of stone surfaces. Laser irradiation at 1064 nm affects the red component of limestone, particularly if they already possess a reddish color. In general, the more intense the original color of the stone the greater are the chromatic changes, but the direction change of the color-parameter affected by a particular process remains the same. It has always been apparent in an atmosphere heavily polluted with soot that the main changes to light-colored stones are the exponential decrease in the parameter L* (darkening-blackening). This has important aesthetic and social implications. However, in the near future it may be that in cleaner atmospheres, perhaps more dominated by organic pollutants, a yellowing process may be of greater concern.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Color changes in architectural limestones from pollution and cleaning

Grossi

Brimblecombe

Esbert

et al. 2007

Color Research & Application

124

View full text Add to dashboard Cite

show abstract

“…Cleaning method effectivenessThe effectiveness of these cleaning methods was assessed by determining the chromatic parameters of the limestone prior to and after cleaning, as well as the overall colour change (∆E* = (∆L* 2 + ∆a* 2 + ∆b* 2 ) ½ )[8,22,[27][28][29]. The reference value was taken to be the colour of the naturally rain-washed limestone, primarily the limestone at the socle of the building, as perFort et al, 2000c.…”

mentioning

confidence: 99%

Assessment of Different Methods for Cleaning the Limestone Façades of the Former Workers Hospital of Madrid, Spain

Pérez-Monserrat¹,

Varas²,

Fort³

et al. 2011

Studies in Conservation

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Four methods for cleaning the limestone facades on what was originally the Workers' Hospital are analyzed in this paper. Due to the pollution in the surrounding air, just twenty years after a prior cleaning operation, sulfate crusts had developed on the entire stone surface of the building. The gypsum mortar used in the original masonry constituted an additional source of sulfur. Limestone is a traditional building material in Madrid and surroundings. The petrography, mineralogy and petrophysical properties of the biomicrite, pelmicrite and biopelmicrite varieties identified in the hospital walls were determined. An analysis of the black layer on the stone surface showed that it consisted primarily of sulfate crusts. The cleaning methods tested were alkaline gels (sodium hydroxide and potassium hydroxide), pressurized hot water, glass bead blasting and latex peeling. The criteria for assessing the effectiveness and potential dangerousness of the various cleaning systems included changes in the chromatic parameters of the clean stone, as well as formation of alteration products (i.e., salts) and modification of the stone surface. The stones cleaned with the three most effective methods as well as the rain-washed stone used as a reference were washed to generate an artificial runoff. The drain water collected was analyzed to determine possible cleaning process by-products. The method found to be most effective and alter the stone surface the least was glass bead blasting, particularly after adjustment of the bead size and pressure conditions used for the test.

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Effect of UV radiation on chromatic parameters in serpentinites used as dimension stones

Navarro

Catarino

Pereira

et al. 2019

Bull Eng Geol Environ

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Colour is an important parameter that must be taken into account if aesthetic homogeneity in both construction and restoration work is to be achieved. In serpentinites, the different degrees of serpentinization or carbonation can influence their final colour. Sunlight, especially ultraviolet (UV) radiation, is a common agent that can decay properties such as hue, lightness, and chroma, and can have a very significant effect on the ageing process of dimension stones. Testing the effects of UV radiation is fundamental for predicting how materials may behave upon exposure. In this work, the surface alteration of materials due to UV radiation by means of arc-xenon lamps was carried out to determine the degree of variation in colour parameters in serpentinites used as dimension stones. It was observed that the effect of UV radiation

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2Colour changes and reactivity to SO of some cladding stones at the “Gran Teatre del Liceu” (Barcelona; Spain)

Cited by 4 publications

References 1 publication

Color changes in architectural limestones from pollution and cleaning

Color changes in architectural limestones from pollution and cleaning

Assessment of Different Methods for Cleaning the Limestone Façades of the Former Workers Hospital of Madrid, Spain

Effect of UV radiation on chromatic parameters in serpentinites used as dimension stones

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