Shades of white are colors that differ only slightly from pure white. Variations of white include what are commonly termed off-white colors, which may be considered part of a neutral color scheme.
91-415: In color theory , a shade is a pure color mixed with black (or having a lower lightness ). Strictly speaking, a "shade of white" would be a neutral gray . This article is also about off-white colors that vary from pure white in hue , and in chroma (also called saturation, or intensity). Colors often considered "shades of white" include cream , eggshell , ivory , Navajo white , and vanilla . Even
182-430: A shell , is a hard, protective outer layer usually created by an animal or organism that lives in the sea. Most seashells are made by mollusks , such as snails , clams , and oysters to protect their soft insides. Empty seashells are often found washed up on beaches by beachcombers . The shells are empty because the animal has died and the soft parts have decomposed or been eaten by another organism. A seashell
273-441: A beach empty and clean, the animal having already died. Empty seashells are often picked up by beachcombers. However, the majority of seashells which are offered for sale commercially have been collected alive (often in bulk) and then killed and cleaned, specifically for the commercial trade. This type of large-scale exploitation can sometimes have a strong negative impact on local ecosystems , and sometimes can significantly reduce
364-569: A blue that is ultramarine at high concentrations appears cyan at low concentrations, allowing it to be used to mix green. Chromium red pigments can appear orange, and then yellow, as the concentration is reduced. It is even possible to mix very low concentrations of the blue mentioned and the chromium red to get a greenish color. This works much better with oil colors than it does with watercolors and dyes. The old primaries depend on sloped absorption curves and pigment leakages to work, while newer scientifically derived ones depend solely on controlling
455-533: A color name in English was in 1926. In 1987, seashell was included as one of the X11 colors. Bone white #F9F6EE Bone white is a yellowish-gray shade of white which represents the color of natural, unbleached bones. Cornsilk #FFF8DC Cornsilk is a color that is a representation of the color of cornsilk . The first recorded use of cornsilk as a color name in English was in 1927. In 1987, cornsilk
546-433: A color this hue shift can be corrected with the addition of a small amount of an adjacent color to bring the hue of the mixture back in line with the parent color (e.g. adding a small amount of orange to a mixture of red and white will correct the tendency of this mixture to shift slightly towards the blue end of the spectrum). The split-primary palette is a color-wheel model that relies on misconceptions to attempt to explain
637-451: A color's complement. It is common among some painters to darken a paint color by adding black paint—producing colors called shades —or lighten a color by adding white—producing colors called tints . However, it is not always the best way for representational painting, as an unfortunate result is for colors to also shift in hue. For instance, darkening a color by adding black can cause colors such as yellows, reds, and oranges, to shift toward
728-441: A few live animals, most responsible collectors do not often over-collect or otherwise disturb ecosystems. The study of the entire molluscan animal (as well as the shell) is known as malacology ; a person who studies mollusks is known as a malacologist . Seashells are commonly found in beach drift, which is natural detritus deposited along strandlines on beaches by the waves and the tides . Shells are very often washed up onto
819-473: A few titles on this subject in the US, see the list of books at the foot of this article.) Identifications to the species level are generally achieved by examining illustrations and written descriptions, rather than by the use of Identification keys , as is often the case in identifying plants and other phyla of invertebrates. The construction of functional keys for the identification of the shells of marine mollusks to
910-501: A flexible hinge. The animal's body is held protectively inside these two shells. Bivalves that do not have two shells either have one shell or they lack a shell altogether. The shells are made of calcium carbonate and are formed in layers by secretions from the mantle. Bivalves, also known as pelecypods, are mostly filter feeders; through their gills, they draw in water, in which is trapped tiny food particles. Some bivalves have eyes and an open circulatory system. Bivalves are used all over
1001-462: A gastropod seashell is a reference to the sacred chank shell Turbinella pyrum of India. In 2003, Maggi Hambling designed a striking 13 ft (4 m) high sculpture of a scallop shell which stands on the beach at Aldeburgh , in England. The goddess of love, Venus or Aphrodite , is often traditionally depicted rising from the sea on a seashell. In The Birth of Venus , Botticelli depicted
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#17327732032231092-422: A girdle, usually come apart not long after death, so they are almost always found as disarticulated plates. Plates from larger species of chitons are sometimes known as "butterfly shells" because of their shape. Only a few species of cephalopods have shells (either internal or external) that are sometimes found washed up on beaches. Some cephalopods such as Sepia , the cuttlefish, have a large internal shell,
1183-409: A hard "test" or shell. After the animal dies, the flesh rots out and the spines fall off, and then fairly often the empty test washes up whole onto a beach, where it can be found by a beachcomber. These tests are fragile and easily broken into pieces. The brachiopods , or lamp shells, superficially resemble clams, but the phylum is not closely related to mollusks. Most lines of brachiopods ended during
1274-431: A major natural history or zoology museum at some point, however, shells with little or no collecting data are usually of no value to science, and are likely not to be accepted by a major museum. Apart from any damage to the shell that may have happened before it was collected, shells can also suffer damage when they are stored or displayed. For an example of one rather serious kind of damage see Byne's disease . There are
1365-616: A medium of exchange in various places, including many Indian Ocean and Pacific Ocean islands, also in North America, Africa and the Caribbean. Seashells have often been used as tools , because of their strength and the variety of their shapes. Because seashells are in some areas a readily available bulk source of calcium carbonate, shells such as oyster shells are sometimes used as soil conditioners in horticulture . The shells are broken or ground into small pieces in order to have
1456-528: A modified complementary pair, with instead of the "true" second color being chosen, a range of analogous hues around it are chosen, i.e. the split complements of red are blue-green and yellow-green. A triadic color scheme adopts any three colors approximately equidistant around a color wheel model. Feisner and Mahnke are among a number of authors who provide color combination guidelines in greater detail. Color combination formulae and principles may provide some guidance but have limited practical application. This
1547-457: A number of books about land and freshwater mollusks, the majority of popular books emphasize, or focus exclusively on, the shells of marine mollusks. Both the science of studying mollusk shells and the hobby of collecting and classifying them are known as conchology . The line between professionals and amateur enthusiasts is often not well defined in this subject, because many amateurs have contributed to, and continue to contribute to, conchology and
1638-522: A number of clubs or societies which consist of people who are united by a shared interest in shells. In the US, these clubs are more common in southerly coastal areas, such as Florida and California , where the marine fauna is rich in species. Seashells are usually identified by consulting general or regional shell-collecting field guides , and specific scientific books on different taxa of shell-bearing mollusks ( monographs ) or "iconographies" (limited text – mainly photographs or other illustrations). (For
1729-473: A sense of visual tension as well as "color harmony"; while others believe juxtapositions of analogous colors will elicit a positive aesthetic response. Color combination guidelines (or formulas) suggest that colors next to each other on the color wheel model ( analogous colors ) tend to produce a single-hued or monochromatic color experience and some theorists also refer to these as "simple harmonies". In addition, split complementary color schemes usually depict
1820-433: A sturdy, and usually readily available, "free" resource which is often easily found on beaches, in the intertidal zone , and in the shallow subtidal zone. As such they are sometimes used second-hand by animals other than humans for various purposes, including for protection (as in hermit crabs ) and for construction. There are numerous popular books and field guides on the subject of shell-collecting. Although there are
1911-412: A surface is white in colorimetry . Below is a chart showing the computer web color shades of white. An achromatic white is a white color in which the red, green, and blues codes are exactly equal. The web colors white and white smoke are achromatic colors. A chromatic shade of white is a white color in which the red, green, and blue codes are not exactly equal, but are close to each other, which
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#17327732032232002-509: A symbol of good luck; and also acts as a signal of danger. Such color associations tend to be learned and do not necessarily hold irrespective of individual and cultural differences or contextual, temporal or perceptual factors. It is important to note that while color symbolism and color associations exist, their existence does not provide evidential support for color psychology or claims that color has therapeutic properties. Seashell A seashell or sea shell , also known simply as
2093-472: A wide gamut of high-chroma colors. In fact, the perceived bias of colors is not due to impurity. Rather, the appearance of any given colorant is inherent to its chemical and physical properties, and its purity unrelated to whether it conforms to our arbitrary conception of an ideal hue. Moreover, the identity of gamut-optimizing primary colors is determined by the physiology of human color vision . Although no set of three primary paints can be mixed to obtain
2184-461: A wooden (usually octagonal) hinged box-frame. The patterns used often featured heart-shaped designs, or included a sentimental expression of love spelled out in small shells. The making of shell work artifacts is a practice of Aboriginal women from La Perouse in Sydney , dating back to the 19th century. Shell work objects include baby shoes, jewelry boxes and replicas of famous landmarks, including
2275-568: Is a complex notion because human responses to color are both affective and cognitive, involving emotional response and judgment. Hence, our responses to color and the notion of color harmony is open to the influence of a range of different factors. These factors include individual differences (such as age, gender, personal preference, affective state, etc.) as well as cultural, sub-cultural, and socially-based differences which gives rise to conditioning and learned responses about color. In addition, context always has an influence on responses about color and
2366-469: Is a tint of white resembling the chalk color. Ghost white #F8F8FF The web color ghost white is a tint of white loosely inspired by traditional representations of ghosts . There is no evidence that this color name was in use before the X11 color names were formulated in 1987. White smoke #F5F5F5 The web color white smoke is displayed on the left. There is no evidence that this color name
2457-449: Is due to the impurity or imperfection of the colorants. In contrast, modern color science does not recognize universal primary colors (no finite combination of colors can produce all other colors) and only uses primary colors to define a given color space . Any three primary colors can mix only a limited range of colors, called a gamut , which is always smaller (contains fewer colors) than the full range of colors humans can perceive. For
2548-439: Is due to the influence of contextual, perceptual, and temporal factors which will influence how color/s are perceived in any given situation, setting, or context. Such formulae and principles may be useful in fashion, interior and graphic design, but much depends on the tastes, lifestyle, and cultural norms of the viewer or consumer. Black and white have long been known to combine "well" with almost any other colors; black decreases
2639-435: Is generally referred to as Color science . While there is no clear distinction in scope, traditional color theory tends to be more subjective and have artistic applications, while color science tends to be more objective and have functional applications, such as in chemistry, astronomy or color reproduction . Color theory dates back at least as far as Aristotle 's treatise On Colors . A formalization of "color theory" began in
2730-553: Is important to add that the CMYK, or process, color printing is meant as an economical way of producing a wide range of colors for printing, but is deficient in reproducing certain colors, notably orange and slightly deficient in reproducing purples. A wider range of colors can be obtained with the addition of other colors to the printing process, such as in Pantone 's Hexachrome printing ink system (six colors), among others. For much of
2821-492: Is usually the exoskeleton of an invertebrate (an animal without a backbone), and is typically composed of calcium carbonate or chitin. Most shells that are found on beaches are the shells of marine mollusks, partly because these shells are usually made of calcium carbonate, and endure better than shells made of chitin. Apart from mollusk shells , other shells that can be found on beaches are those of barnacles , horseshoe crabs and brachiopods . Marine annelid worms in
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2912-424: Is what makes it a shade of white. White #FFFFFF White is a color, the perception of which is evoked by light that stimulates all three types of color sensitive cone cells in the human eye in equal amounts and with high brightness compared to the surroundings. A white visual stimulation will be void of hue and grayness . White is the lightest possible color. Chalk white #FBFFFF Chalk white
3003-570: The CMYK system; in both printing and photography, white is provided by the color of the paper.) These CMY primary colors were reconciled with the RGB primaries, and subtractive color mixing with additive color mixing, by defining the CMY primaries as substances that absorbed only one of the retinal primary colors: cyan absorbs only red (−R+G+B), magenta only green (+R−G+B), and yellow only blue-violet (+R+G−B). It
3094-938: The International Commission on Zoological Nomenclature (ICZN). Large numbers of new species are published in the scientific literature each year. There are currently an estimated 100,000 species of mollusks worldwide. The term seashell is also applied loosely to mollusk shells that are not of marine origin, for example by people walking the shores of lakes and rivers using the term for the freshwater mollusk shells they encounter. Seashells purchased from tourist shops or dealers may include various freshwater and terrestrial shells as well. Non-marine items offered may include large and colorful tropical land snail shells, freshwater apple snail shells, and pearly freshwater unionid mussel shells. This can be confusing to collectors, as non-marine shells are often not included in their reference books. Seashells have been used as
3185-483: The Permian-Triassic extinction event , and their ecological niche was filled by bivalves. A few of the remaining species of brachiopods occur in the low intertidal zone and thus can be found live by beachcombers. Some polychaetes , marine annelid worms in the family Serpulidae , secrete a hard tube made of calcium carbonate, adhering to stones or other shells. This tube resembles, and can be confused with,
3276-716: The Sydney Harbour Bridge and the Sydney Opera House . The shellwork tradition began as an Aboriginal women's craft which was adapted and tailored to suit the tourist souvenir market, and which is now considered high art. Small pieces of colored and iridescent shell have been used to create mosaics and inlays , which have been used to decorate walls, furniture and boxes. Large numbers of whole seashells, arranged to form patterns, have been used to decorate mirror frames, furniture and human-made shell grottos . A very large outdoor sculpture at Akkulam of
3367-400: The cuttlefish bone , and this often washes up on beaches in parts of the world where cuttlefish are common. Spirula spirula is a deep water squid-like cephalopod. It has an internal shell which is small (about 1 in or 24 mm) but very light and buoyant. This chambered shell floats very well and therefore washes up easily and is familiar to beachcombers in the tropics. Nautilus is
3458-501: The 18th century, initially within a partisan controversy over Isaac Newton 's theory of color ( Opticks , 1704) and the nature of primary colors. By the end of the 19th century, a schism had formed between traditional color theory and color science. Color theory is rooted in antiquity, with early musings on color in Aristotle 's (d. 322 BCE) On Colors and Claudius Ptolemy 's (d. 168 CE) Optics . The influence of light on color
3549-468: The 19th century artistic color theory either lagged behind scientific understanding or was augmented by science books written for the lay public, in particular Modern Chromatics (1879) by the American physicist Ogden Rood , and early color atlases developed by Albert Munsell ( Munsell Book of Color , 1915, see Munsell color system ) and Wilhelm Ostwald (Color Atlas, 1919). Major advances were made in
3640-558: The RYB color model, yellow mixed with purple, orange mixed with blue, or red mixed with green produces an equivalent gray and are the painter's complementary colors. One reason the artist's primary colors work at all is due to the imperfect pigments being used have sloped absorption curves and change color with concentration. A pigment that is pure red at high concentrations can behave more like magenta at low concentrations. This allows it to make purples that would otherwise be impossible. Likewise,
3731-582: The Three Primitive Colours Assumed as a Perfect System of Rudimentary Information (London 1826), in which he described how all colors could be obtained from just three. Subsequently, German and English scientists established in the late 19th century that color perception is best described in terms of a different set of primary colors—red, green and blue-violet ( RGB )—modeled through the additive mixture of three monochromatic lights. Subsequent research anchored these primary colors in
Shades of white - Misplaced Pages Continue
3822-415: The amount of absorption in certain parts of the spectrum . When mixing pigments, a color is produced which is always darker and lower in chroma, or saturation, than the parent colors. This moves the mixed color toward a neutral color—a gray or near-black. Lights are made brighter or dimmer by adjusting their brightness, or energy level; in painting, lightness is adjusted through mixture with white, black, or
3913-697: The apparent saturation or brightness of colors paired with it and white shows off all hues to equal effect. A major underpinning of traditional color theory is that colors carry significant cultural symbolism, or even have immutable, universal meaning. As early as the ancient Greek philosophers, many theorists have devised color associations and linked particular connotative meanings to specific colors. However, connotative color associations and color symbolism tends to be culture-bound and may also vary across different contexts and circumstances. For example, red has many different connotative and symbolic meanings from exciting, arousing, sensual, romantic, and feminine; to
4004-451: The circular model in the prediction of color-mixing results. For example, a mixture of magenta and cyan inks or paints will produce vivid blues and violets, whereas a mixture of red and blue inks or paints will produce darkened violets and purples, even though the angular distance separating magenta and cyan is the same as that separating red and blue. In Chevreul's 1839 book The principles of harmony and contrast of colours , he introduced
4095-504: The class Malacostraca (crabs, shrimps and lobsters, for instance), the plates of the exoskeleton may be fused to form a more or less rigid carapace . Moulted carapaces of a variety of marine malacostraceans often wash up on beaches. The horseshoe crab is an arthropod of the family Limulidae . The shells or exuviae of these arachnid relatives are common in beach drift in certain areas of the world. Some echinoderms such as sea urchins , including heart urchins and sand dollars , have
4186-413: The color has marked blue hues, although is otherwise very close to being completely white in the RGB color system. Baby powder #FEFEFA The Crayola crayon color baby powder was introduced in 1994 as part of its specialty Magic Scent crayon collection. It is a very light yellow. Snow #FFFAFA The web color snow is displayed at left. The first recorded use of snow as a color name in English
4277-529: The color range of lightfast synthetic pigments, allowing for substantially improved saturation in color mixtures of dyes, paints, and inks. It also created the dyes and chemical processes necessary for color photography. As a result, three-color printing became aesthetically and economically feasible in mass printed media, and the artists' color theory was adapted to primary colors most effective in inks or photographic dyes: cyan, magenta, and yellow (CMY). (In printing, dark colors are supplemented by black ink, known as
4368-575: The complete color gamut perceived by humans, red, yellow, and blue are a poor choice if high-chroma mixtures are desired. This is because painting is a subtractive color process, for which red and blue are secondary, not primary, colors. Although flawed in principle, the split-primary system can be successful in practice, because the recommended blue-biased red and green-biased blue positions are often filled by near approximations of magenta and cyan, respectively, while orange-biased red and violet-biased blue serve as secondary colors, tending to further widen
4459-655: The contrast between "complementary" or opposing hues that are produced by color afterimages and in the contrasting shadows in colored light. These ideas and many personal color observations were summarized in two founding documents in color theory: the Theory of Colours (1810) by the German poet Johann Wolfgang von Goethe , and The Law of Simultaneous Color Contrast (1839) by the French industrial chemist Michel Eugène Chevreul . Charles Hayter published A New Practical Treatise on
4550-399: The desired effect of raising the pH and increasing the calcium content in the soil. Seashells have played a part in religion and spirituality, sometimes even as ritual objects. Seashells have been used as musical instruments, wind instruments for many hundreds if not thousands of years. Most often the shells of large sea snails are used, as trumpets, by cutting a hole in the spire of
4641-429: The differing responses to light by three types of color receptors or cones in the retina ( trichromacy ). On this basis the quantitative description of the color mixture or colorimetry developed in the early 20th century, along with a series of increasingly sophisticated models of color space and color perception, such as the opponent process theory. Across the same period, industrial chemistry radically expanded
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#17327732032234732-421: The distribution of rare species . Seashells are created by the molluscs that use them for protection. Molluscs have an outside layer of tissues on their bodies – the mantle – which creates the shell material and which connects the shell to the mollusc. The specialized cells in the mantle form the shell using different minerals and proteins . The proteins are then used to create the framework that supports
4823-472: The early 20th century by artists teaching or associated with the German Bauhaus , in particular Wassily Kandinsky , Johannes Itten , Faber Birren and Josef Albers , whose writings mix speculation with an empirical or demonstration-based study of color design principles. One of the earliest purposes of color theory was to establish rules governing the mixing of pigments. Traditional color theory
4914-467: The factors that influence positive aesthetic response to color: individual differences ( ID ) such as age, gender, personality and affective state; cultural experiences ( CE ), the prevailing context ( CX ) which includes setting and ambient lighting; intervening perceptual effects ( P ) and the effects of time ( T ) in terms of prevailing social trends. In addition, given that humans can perceive over 2.8 million different colors, it has been suggested that
5005-426: The family Serpulidae create shells which are tubes made of calcium carbonate cemented onto other surfaces. The shells of sea urchins are called " tests ", and the moulted shells of crabs and lobsters are exuviae . While most seashells are external, some cephalopods have internal shells. Seashells have been used by humans for many different purposes throughout history and prehistory. However, seashells are not
5096-401: The goddess Venus rising from the ocean on a scallop shell. Sea shells found in the creek and backwater of the coast of west India are used as an additive to poultry feed. They are crushed and mixed with jowar maize and dry fish. Seashells, namely from bivalves and gastropods, are fundamentally composed of calcium carbonate. In this sense, they have potential to be used as raw material in
5187-402: The greenish or bluish part of the spectrum. Lightening a color by adding white can cause a shift towards blue when mixed with reds and oranges. Another practice when darkening a color is to use its opposite, or complementary, color (e.g. purplish-red added to yellowish-green) to neutralize it without a shift in hue and darken it if the additive color is darker than the parent color. When lightening
5278-527: The growing shell. Calcium carbonate is the main compound of shell structure, aiding in adhesion . The word seashell is often used to mean only the shell of a marine mollusk . Marine mollusk shells that are familiar to beachcombers and thus most likely to be called "seashells" are the shells of marine species of bivalves (or clams ), gastropods (or snails ), scaphopods (or tusk shells ), polyplacophorans (or chitons ), and cephalopods (such as nautilus and spirula ). These shells are very often
5369-497: The hues from blue-green through blue violet, most grays included. There is a historical disagreement about the colors that anchor the polarity, but 19th-century sources put the peak contrast between red-orange and greenish-blue. Color theory has described perceptual and psychological effects to this contrast. Warm colors are said to advance or appear more active in a painting, while cool colors tend to recede; used in interior design or fashion, warm colors are said to arouse or stimulate
5460-658: The larger science of malacology . Many shell collectors belong to "shell clubs" where they can meet others who share their interests. A large number of amateurs collect the shells of marine mollusks, and this is partly because many shells wash up empty on beaches, or live in the intertidal or sub-tidal zones, and are therefore easily found and preserved without much in the way of specialized equipment or expensive supplies. Some shell collectors find their own material and keep careful records, or buy only "specimen shells", which means shells which have full collecting data : information including how, when, where, in what habitat, and by whom,
5551-485: The late 18th century. The difference (as traced by etymologies in the Oxford English Dictionary ), seems related to the observed contrast in landscape light, between the "warm" colors associated with daylight or sunset, and the "cool" colors associated with a gray or overcast day. Warm colors are often said to be hues from red through yellow, browns, and tans included; cool colors are often said to be
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#17327732032235642-499: The law of color contrast, stating that colors that appear together (spatially or temporally) will be altered as if mixed with the complementary color of the other color, functionally boosting the color contrast between them. For example, a piece of yellow fabric placed on a blue background will appear tinted orange because orange is the complementary color to blue. Chevreul formalized three types of contrast: The distinction between "warm" and "cool" colors has been important since at least
5733-467: The lighting of a room, however, can cause a pure white to be perceived as off-white. Off-white colors were pervasively paired with beiges in the 1930s, and especially popular again from roughly 1955 to 1975. In terms of paint, off-white paints are now becoming more popular, with Benjamin Moore having 152 shades of off-whites, Behr having 167, and PPG has 315. Whiteness measures the degree to which
5824-409: The mixable gamut. This system is in effect a simplified version of Newton's geometrical rule that colors closer together on the hue circle will produce more vibrant mixtures. A mixture produced from two primary colors, however, will be much more highly saturated than one produced from two secondary colors, even though the pairs are the same distance apart on the hue circle, revealing the limitations of
5915-563: The mixing of colored light, Isaac Newton 's color wheel is often used to describe complementary colors, which are colors that cancel each other's hue to produce an achromatic (white, gray or black) light mixture. Newton offered as a conjecture that colors exactly opposite one another on the hue circle cancel out each other's hue; this concept was demonstrated more thoroughly in the 19th century. An example of complementary colors would be magenta and green. A key assumption in Newton's hue circle
6006-414: The most common seashells that wash up on large sandy beaches or in sheltered lagoons . They can sometimes be extremely numerous. Very often the two valves become separated. There are more than 15,000 species of bivalves that live in both marine and freshwater. Examples of bivalves are clams, scallops, mussels, and oysters. The majority of bivalves consist of two identical shells that are held together by
6097-399: The most commonly encountered, both in the wild, and for sale as decorative objects. Marine species of gastropods and bivalves are more numerous than land and freshwater species, and the shells are often larger and more robust. The shells of marine species also often have more sculpture and more color, although this is by no means always the case. In the tropical and sub-tropical areas of
6188-426: The notebooks of Leonardo da Vinci (c. 1490). The RYB primary colors became the foundation of 18th-century theories of color vision , as the fundamental sensory qualities that are blended in the perception of all physical colors, and conversely, in the physical mixture of pigments or dyes . These theories were enhanced by 18th-century investigations of a variety of purely psychological color effects, in particular
6279-404: The notion of color harmony, and this concept is also influenced by temporal factors (such as changing trends) and perceptual factors (such as simultaneous contrast) which may impinge on human response to color. The following conceptual model illustrates this 21st-century approach to color harmony: wherein color harmony is a function ( f ) of the interaction between color/s (Col 1, 2, 3, …, n ) and
6370-579: The number of possible color combinations is virtually infinite thereby implying that predictive color harmony formulae are fundamentally unsound. Despite this, many color theorists have devised formulae, principles or guidelines for color combination with the aim being to predict or specify positive aesthetic response or "color harmony". Color wheel models have often been used as a basis for color combination guidelines and for defining relationships between colors. Some theorists and artists believe juxtapositions of complementary color will produce strong contrast,
6461-399: The only genus of cephalopod that has a well-developed external shell. Females of the cephalopod genus Argonauta create a papery egg case which sometimes washes up on tropical beaches and is referred to as a "paper nautilus". The largest group of shelled cephalopods, the ammonites , are extinct, but their shells are very common in certain areas as fossils . Empty molluscan seashells are
6552-455: The only kind of shells; in various habitats, there are shells from freshwater animals such as freshwater mussels and freshwater snails , and shells of land snails . When the word "seashells" refers only to the shells of marine mollusks, then studying seashells is part of conchology . Conchologists or serious collectors who have a scientific bias are in general careful not to disturb living populations and habitats: even though they may collect
6643-695: The planet, there are far more species of colorful, large, shallow water shelled marine mollusks than there are in the temperate zones and the regions closer to the poles. Although there are a number of species of shelled mollusks that are quite large, there are vast numbers of extremely small species too, see micromollusks . Not all mollusks are marine. There are numerous land and freshwater mollusks, see for example snail and freshwater bivalves . In addition, not all mollusks have an external shell: some mollusks such as some cephalopods (squid and octopuses) have an internal shell, and many mollusks have no shell, see for example slug and nudibranch . Bivalves are often
6734-647: The production of lime . Along the Gulf Coast of the United States , oyster shells were mixed into cement to make "shellcrete" which could form bricks, blocks and platforms. It could also be applied over logs. A notable example is the 19th-century Sabine Pass Lighthouse in Louisiana, near Texas. Many arthropods have sclerites , or hardened body parts, which form a stiff exoskeleton made up mostly of chitin . In crustaceans , especially those of
6825-459: The purported presence of impurities, small amounts of other colors in the paints, or biases away from the ideal primary toward one or the other of the adjacent colors. Every red paint, for example, is said to be tainted with, or biased toward, either blue or yellow, every blue paint toward either red or green, and every yellow toward either green or orange. These biases are said to result in mixtures that contain sets of complementary colors , darkening
6916-474: The resulting color. To obtain vivid mixed colors, according to split-primary theory, it is necessary to employ two primary colors whose biases both fall in the direction, on the color wheel, of the color to be mixed, combining, for example, green-biased blue and green-biased yellow to make bright green. Based on this reasoning, proponents of split-primary theory conclude that two versions of each primary color, often called "cool" and "warm," are needed in order to mix
7007-549: The shell or cutting off the tip of the spire altogether. Various different kinds of large marine gastropod shells can be turned into "blowing shells"; however, the most commonly encountered species used as " conch " trumpets are: Children in some cultures are often told the myth that you can hear the sound of the ocean by holding a seashell to ones ear. This is due to the effect of seashell resonance . Whole seashells or parts of sea shells have been used as jewelry or in other forms of adornment since prehistoric times. Mother of pearl
7098-446: The shells were collected. On the other hand, some collectors buy the more widely available commercially imported exotic shells, the majority of which have very little data, or none at all. To museum scientists, having full collecting data (when, where, and by whom it was collected) with a specimen is far more important than having the shell correctly identified. Some owners of shell collections hope to be able to donate their collection to
7189-570: The species level can be very difficult, because of the great variability within many species and families. The identification of certain individual species is often very difficult, even for a specialist in that particular family. Some species cannot be differentiated on the basis of shell character alone. Numerous smaller and more obscure mollusk species (see micromollusk ) are yet to be discovered and named. In other words, they have not yet been differentiated from similar species and assigned scientific (binomial) names in articles in journals recognized by
7280-785: The three color attributes generally considered by color science: hue , colorfulness and lightness . These confusions are partly historical and arose in scientific uncertainty about color perception that was not resolved until the late 19th century when artistic notions were already entrenched. They also arise from the attempt to describe the highly contextual and flexible behavior of color perception in terms of abstract color sensations that can be generated equivalently by any visual media . Color theory asserts three pure primary colors that can be used to mix all possible colors. These are sometimes considered as red, yellow and blue ( RYB ) or as red, green and blue ( RGB ). Ostensibly, any failure of specific paints or inks to match this ideal performance
7371-403: The unsatisfactory results produced when mixing the traditional primary colors, red, yellow, and blue. Painters have long considered red, yellow, and blue to be primary colors. In practice, however, some of the mixtures produced from these colors lack chromatic intensity . Rather than adopt a more effective set of primary colors , proponents of split-primary theory explain this lack of chroma by
7462-463: The viewer, while cool colors calm and relax. Most of these effects, to the extent they are real, can be attributed to the higher saturation and lighter value of warm pigments in contrast to cool pigments; brown is a dark, unsaturated warm color that few people think of as visually active or psychologically arousing. It has been suggested that "Colors seen together to produce a pleasing affective response are said to be in harmony". However, color harmony
7553-603: The world as food and as a source of pearls. The larvae of some freshwater mussels can be dangerous to fish and can bore through wood. Shell Beach, Western Australia , is a beach which is entirely made up of the shells of the cockle Fragum erugatum . Certain species of gastropod seashells (the shells of sea snails ) can sometimes be common, washed up on sandy beaches, and also on beaches that are surrounded by rocky marine habitat. Chiton plates or valves often wash up on beaches in rocky areas where chitons are common. Chiton shells, which are composed of eight separate plates and
7644-449: Was built around "pure" or ideal colors, characterized by different sensory experiences rather than attributes of the physical world. This has led to several inaccuracies in traditional color theory principles that are not always remedied in modern formulations. Another issue has been the tendency to describe color effects holistically or categorically, for example as a contrast between "yellow" and "blue" conceived as generic colors instead of
7735-486: Was historically primarily a seashell product, although more recently some mother of pearl comes from freshwater mussels. Also see pearl . " Sailor's Valentines " were late 19th-century decorative keepsakes which were made from the Caribbean, and which were often purchased by sailors to give to their loved ones back home for example in England. These valentines consisted of elaborate arrangements of small seashells glued into attractive symmetrical designs, which were encased on
7826-425: Was in 1000. The color snow was included as one of the X11 colors when they were formulated in 1987. Ivory #FFFFF0 Ivory is an off-white color that resembles ivory , the material out of which the teeth and tusks of animals (such as the elephant and the walrus ) are made. It has a very slight tint of yellow . The first recorded use of ivory as a color name in English was in 1385. The color ivory
7917-418: Was in use before the X11 color names were formulated in 1987. The color is also known as Cultured Pearl , one of crayon colors issued by Crayola in its 16-pack of Pearl Brite Crayons. White solid #F4F5FA The web color white solid is displayed on the left. There is no evidence that this color name was in use before the X11 color names were formulated in 1987. Sometimes also known as Ghost White ,
8008-445: Was included as one of the X11 colors when they were formulated in 1987. Floral white #FFFAF0 The web color floral white is displayed at left. There is no evidence that this color name was in use before the X11 color names were formulated in 1987. Seashell #FFF5EE Seashell is an off-white color that resembles some of the very pale pinkish tones that are common in many seashells . The first recorded use of seashell as
8099-477: Was included as one of the X11 colors. Old lace #FDF5E6 Old lace is a web color that is a very pale yellowish orange that resembles the color of an old lace tablecloth. Color theory Color theory , or more specifically traditional color theory , is the historical body of knowledge describing the behavior of colors, namely in color mixing , color contrast effects, color harmony , color schemes and color symbolism . Modern color theory
8190-421: Was investigated and revealed further by al-Kindi (d. 873) and Ibn al-Haytham (d. 1039). Ibn Sina (d. 1037), Nasir al-Din al-Tusi (d. 1274), and Robert Grosseteste (d. 1253) discovered that contrary to the teachings of Aristotle, there are multiple color paths to get from black to white. More modern approaches to color theory principles can be found in the writings of Leone Battista Alberti (c. 1435) and
8281-446: Was that the "fiery" or maximum saturated hues are located on the outer circumference of the circle, while achromatic white is at the center. Then the saturation of the mixture of two spectral hues was predicted by the straight line between them; the mixture of three colors was predicted by the "center of gravity" or centroid of three triangle points, and so on. According to traditional color theory based on subtractive primary colors and
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