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Today it is possible to create veneers that are aesthetically and functionally satisfying, but there are some factors that may compromise the aesthetic results.  The aim of this study was to investigate influence of cement shades and ceramic thickness on the colour of ceramic veneers, but also to study how well try-in pastes match with their corresponding cements. PubMed was used to search for papers using MeSH-terms and keywords. 144 titles and abstracts were read, 29 full texts were read and 24 papers were used in the analysis. All of the studies were in vitro. In 20 studies, it was found that the cement shade influences the colour of the ceramic veneer. Two studies reported that the cement shade had no influence on the colour of ceramic veneers, and two did not draw any conclusions regarding the influence of cement shade. Twelve studies compared different thicknesses of the veneers; all of them found that the thicknesses had an influence on the colour of the veneers. Two out of four studies found no compatibility between try-in pastes and their corresponding cements, while two studies found compatibility for some try-in pastes. The shades of cement and thicknesses of ceramic veneers can influence the colour of the ceramics. The colour of try-in pastes does not always show a similarity with their corresponding cement.

Humans’ perceptual experience of color is very different from what one might expect, given the light reaching the eye. Identical patterns of light are often perceived as different colors, and different patterns of light are often perceived as the same color. Even more strikingly, our perceptual experience is that hues are arranged circularly (with red similar to violet), even though single-wavelength lights giving rise to perceptions of red and violet are at opposite ends of the wavelength spectrum. The goal of this thesis is to understand how perceptual color space arises in the brain, focusing on the arrangement of hue. To do this, we use computational modeling to integrate findings about light, physiology of the visual system, and color representation in the brain. Recent experimental work shows that alongside spatially contiguous orientation preference maps, macaque primary visual cortex (V1) represents color in isolated patches, and within those patches hue appears to be spatially organized according to perceptual color space. We construct a model of the early visual system that develops based on natural input, and we demonstrate that several factors interact to prevent this first model from developing a realistic representation of hue. We show these factors as independent dimensions and relate them to problems the brain must be overcoming in building a representation of perceptual color space: physiological and environmental variabilities to which the brain is relatively insensitive (surprisingly, given the importance of input in driving development). We subsequently show that a model with a certain position on each dimension develops a hue representation matching the range and spatial organization found in macaque V1—the first time a model has done so. We also show that the realistic results are part of a spectrum of possible results, indicating other organizations of color and orientation that could be found in animals, depending on physiological and environmental factors. Finally, by analyzing how the models work, we hypothesize that well-accepted biological mechanisms such as adaptation, typically omitted from models of both luminance and color processing, can allow the models to overcome these variabilities, as the brain does. These results help understand how V1 can develop a stable, consistent representation of color despite variabilities in the underlying physiology and input statistics. This in turn suggests how the brain can build useful, stable representations in general based on visual experience, despite irrelevant variabilities in input and physiology. The resulting models form a platform to investigate various adult color visual phenomena, as well as to predict results of rearing experiments.

ABSTRACT Sexual selection may influence aspects of male morphology associated with territoriality, female choice, aggression and contest success. Attributes that are most commonly selected for include body size, condition, weaponry, endurance and bright coloration. I investigated the relationships between morphology, use of space and home range quality, and access to females. Specifically, I examined the relationships between colour, body size and condition, and whether morphology could predict aggression or contest success. Colour spectral data were analyzed using both traditional measures of colour (hue, chroma, brightness) and principal components. Males with darker, more saturated chests, and more saturated throats, had larger home ranges. Home range quality, as determined by refuge number and prey availability, was associated with blue chests and blue throats and chests, respectively. Males with larger home ranges had higher numbers of associated females and spent more time courting females. Larger males in better condition had darker, more saturated chests. Males in better body condition were also more aggressive. There was a consistent trend for larger males to win more contests, but this relationship was only significant in analyses using traditional measures of colour.

This thesis explores colour as a philosophical means of transit between literature and the visual arts. I explore a new way of thinking about the self and about thought, developmg the significance of colour alongside, and internal to, modes of representation in the modernist movement. The interaction of art and literature is crucial to much debate on modernist aesthetics. DevelopIng the debate into the history of colour phenomena, I argue that colour aHows a philosophical inflection to certain clich6s (such as stream-of-consciousness) that are attached to modernist writing. In the work of Virginia Woolf, Samuel Beckett, Dorothy Richardson and TS Eliot, I argue that the modernist preoccupation with the seeming unpasse between thought and representation can be seen to be 'made visible' through the theme of colour. Colour is a vehicle through which to explore the relation between thought and perception, subject and object, and offers a new way of engagement with recent research into theoretical comparisons between thinking, writing and visual arts.

Colour energy and wellbeing in the context of architecture and design are underestimated in terms of the value they bring to design, branding and real estate development in all sectors, ranging from residential to corporate projects, including the hospitality and luxury industry. Colour, with a particular focus on its latent energy, has not yet been sufficiently explored, researched or discussed, and remains one of the great mysteries of perception. Colour is essential for life and survival, and reaches far beyond art and the decoration of space. The sensation of colour, as an expression of the sense of sight, influences wellbeing and is connected to deeply embedded themes and patterns on emotional, cultural, or personal levels, through which it impacts on wellbeing, health, and decision-making in essential ways, not least because vision has replaced odour as the most essential sense for survival. The majority of all conscious and unconscious decisions are affected by notions of colour, a discipline of constant debate in both art and science. Architecture is somewhere in between, and practising architects are expected to provide the client with individual solutions based on informed decisions. When they do this, however, basing their decisions on experience, unspecified knowledge and intuition, they are often perceived as arrogant. Architecture and the design of space are a constant concern for everyone. The desire to build a home, a temple or a public building in a three dimensional environment is a fundamental urge and as old as mankind itself. Yet perhaps because of these strong impulses, the complexity of creating space is often underestimated. Our body records millions of impressions per minute across all five senses. The five senses keep us alive; they warn, nurture, and alert us, and human perception is based on receiving the vibrations caused by energy fields. These sensory vibrations are directly linked with the human body and it is through them that experiences like I am feeling good in this space and even unconscious memories are triggered. Clients may expect the architect to know everything about the perception of space. Architecture, however, is a very complex matter, and in most academic programs little or no time is allowed for the in-depth study of perception, psychology, colour energy, or wellbeing. Even architecture and interior design are often conflated, and treated as one combined subject rather than two complementary disciplines. What is most striking is that colour is often ignored in Western architecture. Furthermore, there is a bias in the literature and education of the West when compared to the holistic approach in the East. In the Orient, holistic means body, spirit and soul. In the Occident, in contrast, it means body, mind and brain. Spirit and soul are missing. And although the sense of something missing becomes more evident in the West, research fights shy of spirit and soul, and leaves unaddressed questions like: 1. What is the relation of colour energy, wellbeing and space in the Occident and Orient? 2. Why is colour not used more often and more instrumentally to improve wellbeing and influence perception? 3. Where do the inhibitions and obstacles come from that prevent occidental architecture and design from reflecting and applying ancient oriental knowledge and belief to colour healing, health, and wellbeing? As a colour theorist, architect and designer I propose that colour energy offers effective principles that provide an invaluable source for informed architectural decisions, which are genuinely independent of subjective taste or contemporary fashion trends, and that enable a truly holistic approach. This research proposes that wellbeing is both timeless and priceless and that wellbeing, health and perception can be stimulated by colour energy.

This thesis investigates some of the physics of semiconducting low-dimensional structures at low temperatures, as well as investigating the effects of defects on low-dimensional structures and magnetic fields on charge recombination in organic photovoltaics (OPVs). The applications of the systems studied vary from photodetectors, to LEDs, lasers and solar cells. We synthesised Cs2CuCl4 and CsCuCl3 nanoparticles. By varying the ratio of coordination solvents in the synthesis we can control the composition and morphologies of the fabricated nanoparticles, including dots, rods and wires. These nanocrystals showed broadband green emission upon excitation with sub-300 nm radiation, which we showed was due to emission from an intra-band Cu(II) defect. We also fabricated a variety of alkylammonium lead iodide materials. We found that hexylammonium lead iodide and dodecylammonium lead iodide emit broadband red light at low temperatures due to a Frenkel defect (f-centre). Additionally, we see evidence of biexciton emission in dodecylammonium lead iodide films at high excitation densities below temperatures of 225 K. The films in this study were seen to adopt two coexistent phases of dodecylammonium lead iodide, both a monoclinic P121/a structure and an orthorhombic Pbca structure, at room temperature. These films were used as the gain medium in a biexciton vertical cavity laser. This device was constructed from a distributed Bragg reflector coated with dodecylammonium lead iodide, a poly(methylmethacrylate) spacer layer, and an evaporated silver mirror. The onset of lasing was seen at 5.6 × 1018 excitations/cm3 at 75 K. Finally, the modulation of open-circuit voltage and short-circuit current by applied magnetic field in OPV devices made from PIDTPhanQ and PC(71)BM was investigated. We saw that magnetic fields influenced the recombination of charge-transfer (CT) states, and simulations indicated that the formation of CT states had a significant contribution from the bimolecular recombination of free charges. The simulations also showed that singlet CT state lifetimes were much smaller than triplet CT state lifetimes.