For pigments, the primary colors are red, blue & yellow (and not red, blue & green). Why?
348134
Web_Maven got it right but only if you already know the right answer. Here is how it goes.\n \nThe first part you got, when you mix lights of color red, green and blue you can get other colors and white. But why doesn't this work with pigments? Because pigments do not emit light, what they do, is absorb all the other colors except the one(s) you see. If you throw white light on a red pigment, it will absorb all colors except red. If you mix the three pigments, the mix absorbs all colors.
275302
"Normal" color pigments reflect (more precisely, they don't absorb) light having wavelengths corresponding to the perceived color of the pigment, and they absorb light with other frequencies.  The energy associated with the absorbed light goes ends up heating the material (i.e., into exciting atomic and molecular vibrations in the compounds in the pigment).  That energy is ultimately removed by thermal conduction (exciting atomic/molecular vibrations in material adjacent to the material doing the absorption), or re-radiated as low-frequency (e.g., infrared) electromagnetic radiation that we cannot see.\n\nFluorescent pigments differ in that some of the light energy that is absorbed gets re-radiated at wavelengths we can see.  In effect, fluorescent compounds convert incoming light of one wavelength into (visible) light of another wavelength, so the material seems to "glow" with a color corresponding to the wavelengths being emitted.  Normally, the re-emitted light has a longer wavelength (lower photon energy) than that of the absorbed light.  (It is possible for fluorescent emission to occur at a shorter wavelength than that of the absorbed light, but conservation of energy requires that the energy of the absorbed photon be "supplemented" with energy from some other source, such as the vibrational energy of the material or by absorption of multiple photons and emission of a single photon.)\n\nA detailed description of the physics involved can be found at <http://micro.magnet.fsu.edu/primer/techniques/fluorescence/fluorescenceintro.html>\n\nThere are numerous fluorescent compounds, each with distinctive absorption and emission characteristics <http://en.wikipedia.org/wiki/Category:Fluorescent_dyes>.   .  As an example, see the spectra of rhodamine B (a very important fluoroscent dye) at <http://omlc.ogi.edu/spectra/PhotochemCAD/html/rhodamineB.htmlz>.
537209
It depends on how one perceives colour. Some cultures only distinguish two colours, e.g. whitish and blackish, cool colours and warm colours. Most physicist see everything in terms of red or blue. I mean how do you define an indigo band? Where does this band start and stop? How would you divide up the rainbow?\nThe main reason for indigo is symmetry. Green is in the middle and Europeans have traditionally seen three colours on the red side, so three are assigned on the blue side.
792830
colors are generally seen because of organic compounds that reflect light in a certain way.  HCl is an acid that will attack those compounds are various sites, rendering the active parts useless in reflecting the colors that they show while intact
27320
Blue, red, and yellow are primary colors. Purple, orange, and green are secondary colors.\n\nblue+red=purple\nred+yellow=orange\nblue+yellow=green\n\nComplementary colors of a primary color are the secondary color made when the other two primary colors are combined.\n\nRed and green are complementary.\nBlue and orange are complementary.\nYellow and purple are complementary.
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In pigments (like paint) yellow and blue make green.\n\nIn lights, if you mix red and green lights, you get yellow light. If you add in blue light, you get white light, so for lights, yellow and blue make white.
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THE HOW AND WHY OF FLOWER COLOR \nBy Dr. Leonard Perry, Extension Professor \nUniversity of Vermont \n  \n\nThe main reason most of us grow flowers is for their colors. The color provided by flowers and the combinations of colors, and the feelings these evoke, is the main reason I and others I know garden. Yet have you ever thought about what makes flowers the colors that they are or how you can describe these colors to others? \n\nWhat may seem simple on the surface is really a lot more complicated than you might think. The color that you see in flowers is actually the result of reflected light from various plant pigments. \n\nA group of compounds called "anthocyanidins" are the basic ingredients. They are named for the flowers in which they were first found, such as the scarlet "pelargonidin" from the geranium or Pelargonium, the purple "petunidin" from the Petunia, or the blue-violet "delphinidin" from the Delphinium. \n\nIt is these anthocyanidin pigments that biotechnologists are studying to change flower colors. For instance, they've taken the scarlet pelargonidin-producing gene from corn and placed it into petunias to give this flower a novel orange color. \n\nThe gene for delphinidin (blue-violet) has been placed into carnations to make some blue. Other factors within the cell, such as the acidity (pH) and even cell shape, are making the genetic production of blue mums and roses a bit more challenging. \n\nCombine the anthocyanidin compounds with sugar in plants to produce the more common "anthocyanin" pigments responsible for our fall leaf colors, among other colors. There are other pigments in leaves as well, such as the flavonols (yellow) and, of course, chlorophyll (green). Flavonols, and the colorless (to us) flavonoid pigments, not only affect the color caused by primary pigments (co-pigmentation), but by absorbing ultraviolet light they also are readily seen by insects. \n\nIt is the insects and other pollinators, such as moths, for whom flower colors really exist, not for our pleasure. Pollination, and subsequent fruit production, is the main purpose of most flowers. A bee balm (Monarda) that appears red to us, may appear white to an insect. Or what are white and yellow flowers to us may appear light blue to insects. \n\nEver wonder why some flowers such as lungworts (Pulmonaria), forget-me-nots (Myosotis), or other members of the Borage family seem to change color from pink to blue? Other flowers such as larkspur (Delphinium) also may exhibit these changes. This usually indicates to insects that a flower has aged and is past pollination, so move on! \n\nMany flowers may not change color on an individual plant, but may change color, even if slightly, among locations or various conditions. Temperature affects color, hence, there are often more vivid colors in cool northern gardens than hot summer ones. Plant stress, such as from drought, insect attack, or plant nutrition (too much or little) also can cause different levels of pigments in flowers, and. as a result, different colors. \n\nSo the next time you look at flowers in your garden, a catalog, or in a book, think about all those unseen chemicals that cause the color. Think, too, about who in the insect world these flower colors are designed to attract, and what colors they may be seeing!
266419
It likely has to do with the energetics of each isomer. The trans conformation absorbs in the violet range of the color spectrum (the complement of yellow). The cis version likely absorbs in the higher ultraviolet range which thus explains its lack of color.
842093
Chlorophyll comes in multiple colors, the pigment itself is irrelevent. The the only thing that matters is that the chlorophyll is present.
197523
Everyone sees everything a little differently than others.  As for colours, it's how your eyes may process light and how your brain may interpret that light.  \n\nIf you're seeing blue while I see red or vise-versa, there's a big problem because those two colors are opposites (actually red and cyan, which is kinda blue).
728020
any solution gives colour due to the fact that the outermost electrons absorb the energy and move to a highre orbit corrospondingly. when they come back to their orignal state, the enegry is emitted in the form of photons, which may have the wavelength crrspndngly to a colour.
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It is usually the metal. The metal responsible for the color can be the cation, like Cu+2 in blue CuSO4, or it can be in the anion, like CrO4= in yellow Na2CrO4. Sulfur is a nonmetal, but its presence in compounds intensifies the color. CuS is an opaque dark brown. The nonmetallic ion thiocyanate, CNS-, reacts with yellow ferric [iron(III)] ion to form a brilliant red complex.\n\nAdditional detail: The metal, of course!
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the colour of plants depend on various colouring agents called pigments. some pigments (cytochromes) found in the leaf include chlorophylla,b(green), carotenoids(yellow-orange), xanthophylls(yellow). the colour of the leaf depends on the proportion in which these pigments are present(as these pigments play an important role in photosynthesis, they are present in the chloroplasts present in the leaves). also chlorophyll a is called universal pigment as all plants contain it and other pigments are called accesory pigments.
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Good question\nFlower colors of red, pink, blue and purple come mainly from the pigments called anthocyanins. Anthocyanins are water soluble pigments in the class of \nchemicals called flavanoids, which are phenolics. Anthocyanins are found in the \ncell vacuoles and are glucosides meaning they contain a sugar molecule. \n\nA classic experiment uses the anthocyanins in red cabbage as a pH indicator \nbecause anthocyanins change color depending on the pH. You could do the same \nthing with flower petals. An easy way is to crush a red rose petal on a white \nplate with the back of a spoon and add either vinegar (acid) or baking soda \n(base) and note the color change. A college lab manual has an experiment on \nchromatography of flower anthocyanins (Witham et al. 1971).\n\nFlowers may also contain another class of pigments called carotenoids, which \nare responsible for red in tomato and orange in carrot root. Carotenoids are \nred, yellow and orange in color. They do not reside in the vacuole but in \norganelles called plastids, either in green chloroplasts or in nongreen \nchromoplasts
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Predominantly red and blue - there are peaks at these ends on the absorption spectrum:(http://www.mbari.org/staff/ryjo/cosmos/Cabs.html)\nBasically, they DON'T use much green - it is reflected back, so is what is seen by your eyes - hence green plants appear green!\nThe main pigments in green plants are chlorophyll-a and chlorophyll-b (which absorb light at those particular wavelengths/colours shown in the diagram) but there are also other pigments used in plants and algae.\n\n-Tara mentioned photosystems - yup, there are 2 photosystems used in the light reactions of photosynthesis - the light energy is absorbed by the pigments in the 'antenna complex' of PSII, which then transfer this energy toward the centre Chl-a molecule ("reaction centre chlorophyll") of that photosystem, exciting an electron which is passed down an 'electron transport chain' to PSI, etc... (if you don't need to know it yet, it's sounds like a scary long process!) - but although I believe the reaction centre chlorophylls may absorb light best only at the red end, there are other pigments in the photosystems which would be absorbing at the blue end as well I should think - blue light is higher energy (shorter wavelength) than red light, so this higher energy light would be absorbed by pigments nearer the edges of the antenna complex, and as the light is transferred through to the reaction centre chlorophyll it would lose energy in the process, and thus probably more toward the red end of the spectrum by the time it arrives. http://en.wikipedia.org/wiki/Photosystem
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The quote from the link explains how yellow is a combination of colors and when added to blue all the colors are represented and the result is white light.  This has to do with the fact that the normal human eye has only three different color receptors and many colors we see are mixtures. \n\n"White is the combination of all colors of light. In other words, the color white is seen when the red, green and blue channels all send signals to the brain. It follows that red light plus green light plus blue light produces white light. However red plus green without the blue produces yellow. By deduction, yellow light plus blue light most produce white light."
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There has to be more info than that!\n\nThe only possible explanation I can give would be if you blue kernals with red kernals.  If mixed, they could produce purple.  The parent kernals could have a mix of dominant and recessive blue and red traits and still produce purple.