True Colors: Chromaticity, Realism and Technological Honesty

I propose an application of agential realism to my practice as research, a film about my mother getting one tattoo covered with a new one, to investigate the material-discursive role played by the camera in determining meaning within the film image. I use my practice as a comparative case study, considering how a specific camera apparatus determines and negotiates standards of colour accuracy, and what it means to remove those colour values in post-production. I argue that the different colour processing of the same footage produces perceptible onto-epistemological difference, even while it remains indexically equivalent. Second, I will show exactly how this particular digital photosensitive technology meets the pro-filmic event to record colour, enacting agencies that reduce matter to fit a specifically programmed colour system, prior to any manipulation in post-production. The system itself draws the boundaries of accuracy it claims to achieve, with inevitable ethical implications.

The Effect of Brilliant Blue-Based Plaque-Staining Agents on Aesthetic Orthodontic Appliances

Orthodontic appliances discolour over treatment time, and a yellowish plaque builds up on the contact area of the brackets, adhesive and teeth. Brilliant Blue-based plaque-staining agents (BBPSAs), which increase tooth brushing efficiency, have the potential to support the maintenance of proper oral hygiene during orthodontic treatment. However, they exhibit strong colouring properties, and their impact on the aesthetics of braces remains unclear. Therefore, the aim of this study was to investigate the influence of commercially available BBPSAs on the colour of aesthetic orthodontic materials. A light-cured, colour-changing orthodontic adhesive and new-generation, monocrystalline, sapphire brackets were chosen for the experiments. The effect of the staining agent on the tested materials was investigated in terms of the reaction temperature and time, as well as the presence of black tea-induced impurities on the materials. The CIELAB (Commission Internationale de L’éclairage L* a* b*) colour system parameters were measured, and the colour differences (ΔE*ab and ΔE00—the Commission Internationale de L’éclairage 2000 colour-difference) were determined for the materials under several experimental conditions. The braces’ green-red colour expression was positively affected by the BBPSA. Under in vitro conditions, the regular use of the BBPSA for 90 days visibly improved the unfavourable colour change caused by the black tea.

Colors Inspired by Nature Analyzed in Two Residential Buildings Designed by Victor Horta

The aim of the article is to present the results of research on colors carried out in two residential buildings in Brussels, designed by Victor Horta: The Tassel House (1893–1894) and The Horta House (1898–1901), representing the Art Nouveau style for which the main source of inspiration was nature. The purpose of the research was to check whether the selection of colors in the buildings was also inspired by nature. The investigation applied methods of archive studies, literature review, field survey and comparative analysis of 251 color samples taken in the interiors and façades of the two houses, compared to the 307 color samples collected in the natural environment within the radius of 700 m from the two locations. The samples were described using the Natural Colour System® chart. The research results revealed that the value of the color-matching indicator for the comparison of the color samples collected in the two examined buildings and the samples of predominant colors observed in the natural environment was determined at the average level of 92.5%. The conclusions from the study confirmed the significance of drawing inspiration from nature in the field of colors selection in the two analyzed buildings designed by Victor Horta.

Colour Preferences and Personality Traits

Colours are important features in human and natural environments and are related to several psychological functions. However, a possible relation between colour preferences and personality traits is scarcely investigated. The aim of the present study was to find out whether differences in preferences for colours also reflected differences in Big Five personality traits. The sample consisted of 206 individuals voluntarily recruited from a student sample. The participants chose one of six primary colours (blue, green, red, yellow, black, white) from the Natural Colour System (NCS) as their favorite colour. Personality traits were measured with the Big Five Inventory-44 (BFI-44. Blue and yellow was the most and least preferred chromatic colour, respectively. There were no gender differences in preferences for the chromatic colours, but more women preferred white and men preferred black. Compared to the rest of the sample, the blue group had higher scores on agreeableness and extraversion, and the red group had lower scores on agreeableness. Pairwise comparisons showed that the blue group had higher scores on agreeableness and extraversion than the red group, and higher scores on agreeableness compared to the green group. There were no significant personality differences for the other chromatic and achromatic colour groups.

Fabrication of smartphone-based colorimetric device for detection of water leaks

South Africa is a water-scarce country due to the shortage of rainfall. This scarcity is further exacerbated by the loss of water through leakage from faulty pipes. This paper reports on the use of a simple microfluidic device in the early detection of water leakages. The microfluidic paper-based device (µPADs) were prepared by printing patterns of wax (100 μm width) on the paper surface and melting the wax into the paper to form hydrophobic barriers. Solutions of lower to higher pH were also prepared and were introduced to the chlorophenol red test strips and a range of colours from yellow (lower pH) to purple (higher pH) were obtained. The digital images obtained with the μPADs were analysed using the CIELab colour system. The optimized pH range was wider than the typical grayscale-based image analysis and was successful for a wide pH range of 2–12. The QR codes attached to the strips enable tracking to obtain the real-time location from which leakage was detected. The study conclusively shows that the combination of digital image analysis and a μPAD device is highly efficient for quantitative analysis, and thus useful for the detection of household water leaks.

Not just shades of grey: life is full of colour for the ocellate freshwater river stingray (Potamotrygon motoro)

Previous studies have shown that marine stingrays have the anatomical and physiological basis for colour vision, with cone spectral sensitivities in the blue to green range of the visible spectrum. Behavioural studies on Glaucostegus typus also showed that blue and grey can be perceived and discriminated. The present study is the first to assess visual opsin genetics in the ocellate river stingray (Potamotrygon motoro) and test if individuals perceive colour in two alternative forced choice experiments. Retinal transcriptome profiling using RNA-Seq and quantification demonstrated the presence of lws and rh2 cone opsin genes and a highly expressed single rod (rh1) opsin gene. Spectral tuning analysis predicted these vitamin-A1 based visual photopigments to exhibit spectral absorbance maxima at 461 nm (rh2), 496 nm (rh1), and 555 nm (lws); suggesting the presence of dichromacy in this species. Indeed, P. motoro demonstrates the potential to be equally sensitive to wavelengths from 380 nm to 600 nm of the visible spectrum. Behavioural results showed that red and green plates, as well as blue and yellow plates, were readily discriminated based on colour; however, brightness differences also played a part in the discrimination of blue and yellow. Red hues of different brightness were distinguished significantly above chance level from one another. In conclusion, the genetic and behavioural results support prior data on marine stingrays. However, this study suggests that freshwater stingrays of the family Potamotrygonidae may have a visual colour system that has ecologically adapted to a riverine habitat.

The impact of trace metal cations and absorbed water on colour transition of turquoise

Thirty-five gem-quality turquoise samples with various colours were investigated using energy-dispersive X-ray fluorescence spectroscopy, ultraviolet–visible spectroscopy, Fourier-transform infrared spectroscopy and scanning electron microscopy. Sample chemical and spectral analyses indicate that Fe 3+ contributes to green hue of turquoise, whose absorption band exhibits a bathochromic shift from 426 to 428 nm with increasing V content in the solid-solution series turquoise-chalcosiderite. V 3+ enhances absorption in the blue and orange regions, and Cr 3+ increases absorption in the green region, both of which are responsible for the vivid greenish yellow in faustite. Substitutions of Al by medium-sized trivalent cations (primarily Fe 3+ and V 3+ ) enhance polarity of the phosphate group (PO 4 ) 3− , resulting in strong absorption in the infrared spectra for analogues of turquoise. The reflectivity ratio ( R OH ) of the double absorption peaks at 781 and 833 cm −1 allows faustite to be distinguished from turquoise and chalcosiderite, with a value greater than 1, while V-rich faustite only has a single absorption peak at 798 cm −1 . An increasing amount of absorbed water contributes to blue chroma in turquoise and has a negative effect on lightness based on the CIE 1976 L * a * b * colour system. Loose turquoise with a low specific gravity tends to display greater colour differences with a significant decrease in lightness.

Characterization of a Natural, Stable, Reversible and Colourful Anthocyanidin Network from Sphagnum Moss Based Mainly on the Yellow Trans-Chalcone and Red Flavylium Cation Forms

Anthocyanins with various functions in nature are one of the most important sources of colours in plants. They are based on anthocyanidins or 3-deoxyanthocyanidins having in common a C15-skeleton and are unique in terms of how each anthocyanidin is involved in a network of equilibria between different forms exhibiting their own properties including colour. Sphagnorubin C (1) isolated from the cell wall of peat moss (Sphagnum sp.) was in fairly acidic and neutral dimethyl sulfoxide characterized by nuclear magnetic resonance (NMR) and ultraviolet–visible (UV–vis) absorption techniques. At equilibrium, the network of 1 behaved as a two–component colour system involving the reddish flavylium cationic and the yellow trans–chalcone forms. The additional D- and E-rings connected to the common C15-skeleton extend the π-conjugation within the molecule and provide both bathochromic shifts in the absorption spectra of the various forms as well as a low isomerization barrier between the cis- and trans-chalcone forms. The hemiketal and cis-chalcone forms were thus not observed experimentally by NMR due to their short lives. The stable, reversible network of 1 with good colour contrast between its two components has previously not been reported for other natural anthocyanins and might thus have potential in future photochromic systems. This is the first full structural characterization of any naturally occurring anthocyanin chalcone form.

Variation of Heartwood Proportion and Wood Colour from Fast Grown 5-Year-Old Teak

The heartwood percentage and wood colour of fast plantation grown teak destined for harvest at 5 years of age were characterized using automatic image processing ’ImageJ’ routines and CieLab’s colour system with the following coefficients: L for lightness, a* for redness and b* for yellowness. Analyses were conducted on material from different dry and wet sites. Comparison with 6-year old plantation from a dry site was conducted to study differences arising in older trees. Analyses of variation of those properties between and within different tree diameter classes were also conducted. The results showed that brightness, redness and yellowness values of 5-year old teak trees were 60.7, 10.7 and 23.1, respectively. Tree clone had a more dominant effect on wood colour and heartwood proportion than site, thus if specific colour preferences are needed of plantation trees, clone selection is important. The drier site produced larger proportions of heartwood in trees, as well as a more attractive figure. The trees produced heartwood proportions of 20% and 14% from the dry and wet sites respectively. On average, these 5 year old teak trees already produced 18% heartwood. Faster tree growth (larger diameter) appeared to have produced significantly larger heartwood proportions. Radially, the palest colour (the highest L but the lowest a*b* parameters) occurred in an area between heartwood and sapwood indicating the presence of a transition zone in all the tree samples.

PENGARUH KADAR AIR TERHADAP NILAI WARNA CIE PADA GULA SEMUT

Colour is one of the essential attributes as product quality criteria that determine the acceptance of a product by consumers. Granulated palm sugar is a crystalline form, which is hygroscopic. The purpose of this study was to study the colour changes through the CIELab (L, a and b) colour system to the changes in the moisture content of granulated palm sugar during storage. Changes in the values of L, a and b were observed during storage at 30oC and 76% RH. The results showed that the moisture content of granulated palm sugar increased from 3.84% wb to 8.40% wb for 10 hours of storage. The L value tends to decrease with an increasing water content which causes it to turn dark brown. While the cost of a tends to increase with increasing moisture content, the colour of the granulated palm sugar to reddish. The same thing happened to the value of b, which increases with the moisture content of granulated palm sugar and causes it tends to yellowish. Thus the change in ant sugar moisture content gives a significant difference to the L, a and b values during storage.