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Colour is visual identification or perception of a property derived from spectrum of light by human eyes. When a beam of light from sun or light source passes through a glass prism, it dispersed in to seven colours of rainbow. Sunlight has a high color temperature, a fairly uniform spectrum and is considered a standard for white light. A rainbow is an optical and meteorological phenomenon caused by reflection and refraction of light in water droplets present in the atmosphere. The rainbow colours are violet, indigo, blue, green, yellow, orange and red (vibgyor). Electromagnetic radiation in the visible range is generally called as light.
Colour Literacy Forum #8
Colours of Objects and Colours of Illumination2024 •
Our visual system detects variations in the intensity and overall balance of spectral composition of the light reaching our eyes, but also does much more, seemingly instantly arriving at unconscious estimates of the overall spectral reflectances of objects, and of the intensity and overall balance of spectral composition of the light illuminating those objects. We perceive these unconscious estimates of spectral properties as colours. Colours of light can be described in terms of the attributes of hue, brightness and either saturation or colourfulness, while colours of objects can be described in terms of the more familiar attributes of hue, lightness and chroma, among others. Using an orange cube on a tiled floor as an illustration, this presentation will describe and contrast these six colour attributes and show how they apply to our superimposed colour perceptions (1) of objects, (2) of the light illuminating objects, and (3) of the light reaching our eyes from objects.
BEST Journal
COLOUR AS A TOOL TO CREATE GRAPHICAL STATEMENT2014 •
Light is the source of colour. Colour is the impression received by the mind from certain stimulations of the retina. Colour perception occurs because objects reflect or transmit light, which enters the eye, acts upon the optic nerve, and causes the sensation of light and colour in the brain. Light rays or waves which vary in length and rate of vibration produce different sensations and appear as different colours. There is an optical instrument known as spectroscope which breaks up or decomposes light and reveals the fundamental colours as arranged in the spectrum. At one end of the spectrum there is the violet colour which has the shortest visible waves, at the other end is red, which has the longest visible rays. The other colours are produced by the intermediate waves. Objects are usually able to reflect part of a light beam and absorb other parts. For example, if an object appears green it absorbs all the other colours that make up while light and reflects only green.
CLARA - Classical Art and Archaeology, vol. 7
Chromatic Variation in Late Antique Rainbows2021 •
Depictions of rainbows in late antique and early Byzantine art follow the normal sequence of the spectral colours, only some bows exclude blue and violet. Another characteristic feature of the late antique rainbow is the inclusion of white and the non-spectral hue pink. In order to investigate chromatic characteristics, I use as case studies the comparatively few extant rainbow images of third-to sixth-century date from Thessaloniki, Constantinople, Rome and Ravenna. The rainbows, depicted in a floor mosaic, three illuminated manuscripts and three monumental wall mosaic decorations, are either part of narratives or rainbow-patterned borders used to frame other scenes. To throw light on the chromatic variations, ancient descriptions of rainbows are brought into the discussion and the representations are seen in relation to meteorological research. I propose that the late antique rainbow images follow two visual traditions, both of which can be traced back to the Hellenistic period and both of which are grounded in scientific research. One is the sunrise/sunset rainbow that ranges from red to green. I argue that the exclusion of blue/violet may be due to its being more difficult to see against the sky, the wavelength of violet being closest to the boundary beyond which coloured light tends to look black. The variant type, found especially in the church mosaics, covers the whole spectrum from red via green to violet as well as pink and white. I suggest that the non-spectral pink hues can be understood as the gradations of red that can sometimes be observed in the natural bow and that the white band provides highlight, which combined with a silver line indicates a strong luminance. The dictionary defines a rainbow as 'an arch of colours formed in the sky in certain circumstances, and caused by the refraction and dispersion of the sun's light by rain or other water droplets in the atmosphere. The colours of the
Colour and light are things that all seeing persons have often reason to refer to, comment and discuss. Such discussions often end up in misunderstandings due to the fact that both light and colour have several – and often conflicting – meanings. This causes problems for professionals in either colour or light or both, for example when quantifying light, discussing light qualities or specifying an exact colour and its characteristics. This paper summarises a project that aimed at sorting out the confusions and at contributing to a better understanding across different disciplines and professions dealing with colour and light. The project identified numerous conflicting usages and potential causes of misunderstanding in the colour and light terminology. A careful analysis of the most important concepts and their usages was carried out. Three main causes for potential misunderstandings of colour and light terminology were found: 1) confusing the different ways of understanding colour and light through physics, human perception or attempts to combine the two. 2) the confusions caused by different modes of appearance of colour and light and 3) the confusions arising from different of modes of perception.
Journal of the International Colour Association
The Elements of Colour I: Colour Perceptions, Colour Stimuli, and Colour Measurement2023 •
This paper presents an extended consideration of the question of what colours are from a scientific perspective by reviewing the connections between colour perceptions, colour stimuli, and colour measurement. The colour of an isolated light can be understood to be the way in which we perceive the overall balance of its spectral composition relative to that of daylight; "overall" here meaning at the level of its long-, middle-and short-wavelength components, as detected by the human visual system. Our ability to detect variations in this overall balance, first demonstrated by Newton, is now understood to rely on comparison of the responses of three receptor types by the process of cone opponency. The colour perceived as belonging to an object when it is freely examined in daylight, which we tend to think of as the (seemingly) intrinsic colour of the object, can similarly be understood to be the way in which we perceive its overall spectral reflectance, again at the level of its long-, middle-and short-wavelength components, as detected by the human visual system. Colorimetric measures are designed to quantify for practical purposes precisely these human-perceiver-dependent "overall" properties of spectral distributions and spectral reflectances, by ignoring physical differences that we do not perceive as colour differences. In defining two senses of word colour, "perceived colour" and "psychophysical colour", the CIE International Lighting Vocabulary in effect expresses a pluralist ontology of colour that acknowledges that we may wish to use the word "colour" either for our perceptions of colour, or for the measurable, human-perceiver-dependent properties that dispose physically different lights or objects to appear the same colour in the same context.
2018 •
مجلة مرکز الدراسات البردية والنقوش جامعة عين شمس
العلاج بالفضلات الآدمية وإفرازاتها ضمن وصفات البرديات الطبية في مصر القديمة Treatment with human waste and secretions within Medical Papyrus Recipes in Ancient Egypt2024 •
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Localized prostate cancer treated with external beam radiation therapy: Long-term outcomes at a European comprehensive cancer centre2016 •
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Hyperuricemia influences tryptophan metabolism via inhibition of multidrug resistance protein 4 (MRP4) and breast cancer resistance protein (BCRP)2013 •
International Journal of Environmental Research and Public Health
Environmental Conditions of Dance Rooms and Its Impact on Dance Conservatories Teachers’ Health (An Andalusian Study)2021 •
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Qualitative and quantitative analysis of the uptake of lipoplexes by villous placenta explants2019 •
2007 •
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Segregación y fronteras simbólicas en La Carpio, una comunidad centroamericana2011 •