Wavelengths of Vibgyor Colors - General Knowledge Today
Is it just amount of photons (intensity) or is there any relation defines color, that frequency is just another face of the wavelength and that they. Color is our perception of the frequency of light. The higher the F (and Intensity has no relation with frequency and wavelength. Intensity is. It always seems to look dark compared to other sources at equal intensity. . Frequency determines color, but when it comes to light, wavelength is the easier thing to measure. .. Colour is a law of nature in relation with the sense of sight.
Other species are sensitive to only two axes of color or do not perceive color at all; these are called dichromats and monochromats respectively. A distinction is made between retinal tetrachromacy having four pigments in cone cells in the retina, compared to three in trichromats and functional tetrachromacy having the ability to make enhanced color discriminations based on that retinal difference.
As many as half of all women are retinal tetrachromats. Behavioral and functional neuroimaging experiments have demonstrated that these color experiences lead to changes in behavioral tasks and lead to increased activation of brain regions involved in color perception, thus demonstrating their reality, and similarity to real color percepts, albeit evoked through a non-standard route. Afterimages After exposure to strong light in their sensitivity range, photoreceptors of a given type become desensitized.
For a few seconds after the light ceases, they will continue to signal less strongly than they otherwise would. Colors observed during that period will appear to lack the color component detected by the desensitized photoreceptors.
This effect is responsible for the phenomenon of afterimagesin which the eye may continue to see a bright figure after looking away from it, but in a complementary color. Afterimage effects have also been utilized by artists, including Vincent van Gogh. Color constancy Main article: Color constancy When an artist uses a limited color palettethe eye tends to compensate by seeing any gray or neutral color as the color which is missing from the color wheel. For example, in a limited palette consisting of red, yellow, black, and white, a mixture of yellow and black will appear as a variety of green, a mixture of red and black will appear as a variety of purple, and pure gray will appear bluish.
In reality, the visual system is constantly adapting to changes in the environment and compares the various colors in a scene to reduce the effects of the illumination. If a scene is illuminated with one light, and then with another, as long as the difference between the light sources stays within a reasonable range, the colors in the scene appear relatively constant to us. This was studied by Edwin Land in the s and led to his retinex theory of color constancy.
Both phenomena are readily explained and mathematically modeled with modern theories of chromatic adaptation and color appearance e. Color naming See also: Lists of colors and Web colors This picture contains one million pixels, each one a different color Colors vary in several different ways, including hue shades of redorangeyellowgreenblueand violetsaturationbrightnessand gloss.
Some color words are derived from the name of an object of that color, such as " orange " or " salmon ", while others are abstract, like "red". In the study Basic Color Terms: Their Universality and EvolutionBrent Berlin and Paul Kay describe a pattern in naming "basic" colors like "red" but not "red-orange" or "dark red" or "blood red", which are "shades" of red.
The next colors to be distinguished are usually red and then yellow or green. All languages with six "basic" colors include black, white, red, green, blue, and yellow. The pattern holds up to a set of twelve: Associations Individual colors have a variety of cultural associations such as national colors in general described in individual color articles and color symbolism. The field of color psychology attempts to identify the effects of color on human emotion and activity.
Chromotherapy is a form of alternative medicine attributed to various Eastern traditions. Colors have different associations in different countries and cultures. For example, researchers at the University of Linz in Austria demonstrated that the color red significantly decreases cognitive functioning in men. The outer curved boundary is the spectral or monochromatic locus, with wavelengths shown in nanometers. The colors depicted depend on the color space of the device on which you are viewing the image, and therefore may not be a strictly accurate representation of the color at a particular position, and especially not for monochromatic colors.
Most light sources are mixtures of various wavelengths of light. Many such sources can still effectively produce a spectral color, as the eye cannot distinguish them from single-wavelength sources.
For example, most computer displays reproduce the spectral color orange as a combination of red and green light; it appears orange because the red and green are mixed in the right proportions to allow the eye's cones to respond the way they do to the spectral color orange.
A useful concept in understanding the perceived color of a non-monochromatic light source is the dominant wavelengthwhich identifies the single wavelength of light that produces a sensation most similar to the light source. Dominant wavelength is roughly akin to hue. There are many color perceptions that by definition cannot be pure spectral colors due to desaturation or because they are purples mixtures of red and violet light, from opposite ends of the spectrum.
Some examples of necessarily non-spectral colors are the achromatic colors black, gray, and white and colors such as pinktanand magenta. Two different light spectra that have the same effect on the three color receptors in the human eye will be perceived as the same color.
They are metamers of that color. This is exemplified by the white light emitted by fluorescent lamps, which typically has a spectrum of a few narrow bands, while daylight has a continuous spectrum. The human eye cannot tell the difference between such light spectra just by looking into the light source, although reflected colors from objects can look different.
This is often exploited; for example, to make fruit or tomatoes look more intensely red. Similarly, most human color perceptions can be generated by a mixture of three colors called primaries. This is used to reproduce color scenes in photography, printing, television, and other media.
There are a number of methods or color spaces for specifying a color in terms of three particular primary colors. Each method has its advantages and disadvantages depending on the particular application.
No mixture of colors, however, can produce a response truly identical to that of a spectral color, although one can get close, especially for the longer wavelengths, where the CIE color space chromaticity diagram has a nearly straight edge.
Because of this, and because the primaries in color printing systems generally are not pure themselves, the colors reproduced are never perfectly saturated spectral colors, and so spectral colors cannot be matched exactly. However, natural scenes rarely contain fully saturated colors, thus such scenes can usually be approximated well by these systems. The range of colors that can be reproduced with a given color reproduction system is called the gamut.
The CIE chromaticity diagram can be used to describe the gamut. Another problem with color reproduction systems is connected with the acquisition devices, like cameras or scanners. The characteristics of the color sensors in the devices are often very far from the characteristics of the receptors in the human eye.
Light: Electromagnetic waves, the electromagnetic spectrum and photons
In effect, acquisition of colors can be relatively poor if they have special, often very "jagged", spectra caused for example by unusual lighting of the photographed scene. A color reproduction system "tuned" to a human with normal color vision may give very inaccurate results for other observers. The different color response of different devices can be problematic if not properly managed.
For color information stored and transferred in digital form, color management techniques, such as those based on ICC profilescan help to avoid distortions of the reproduced colors. Color management does not circumvent the gamut limitations of particular output devices, but can assist in finding good mapping of input colors into the gamut that can be reproduced.
Additive coloring Additive color mixing: Additive color is light created by mixing together light of two or more different colors. Redgreenand blue are the additive primary colors normally used in additive color systems such as projectors and computer terminals. Subtractive coloring Subtractive color mixing: The color that a surface displays comes from the parts of the visible spectrum that are not absorbed and therefore remain visible.
Without pigments or dye, fabric fibers, paint base and paper are usually made of particles that scatter white light all colors well in all directions.
When a pigment or ink is added, wavelengths are absorbed or "subtracted" from white light, so light of another color reaches the eye. If the light is not a pure white source the case of nearly all forms of artificial lightingthe resulting spectrum will appear a slightly different color.
Red paint, viewed under blue light, may appear black. Red paint is red because it scatters only the red components of the spectrum. If red paint is illuminated by blue light, it will be absorbed by the red paint, creating the appearance of a black object. Structural color Further information: Structural coloration and Animal coloration Structural colors are colors caused by interference effects rather than by pigments.
Light: Electromagnetic waves, the electromagnetic spectrum and photons (article) | Khan Academy
Color effects are produced when a material is scored with fine parallel lines, formed of one or more parallel thin layers, or otherwise composed of microstructures on the scale of the color's wavelength.
If the microstructures are spaced randomly, light of shorter wavelengths will be scattered preferentially to produce Tyndall effect colors: If the microstructures are aligned in arrays, for example the array of pits in a CD, they behave as a diffraction grating: If the structure is one or more thin layers then it will reflect some wavelengths and transmit others, depending on the layers' thickness.
Structural color is studied in the field of thin-film optics. I personally use a monochrome CCD, which means that my sensor doesn't have a bayer array. Instead I use a separate filter wheel with RGB or other filters to get my different color frames and then combine them into a color image.
So then having all the photons be the same wavelength, brightness of each pixel will be proportional to the amount of photons that impacted that particular pixel? ALL photons, of ANY frequency with enough energy to excite an electron will be able to contribute to the pixel's final value.
This is why filters are important. We reject the wavelengths that we DON'T want to see.
An unfiltered CCD typically has a range of wavelengths that it responds to, with light of around 1, nm being the lowest energy capable of exciting an electron, to nm being the highest energy light that it can respond to. Higher energy light is usually absorbed in in the small features of the CCD pixels before it can reach the photosensitive layer.
If frequency defines intensity too, would that mean that one blue photon with higher frequency could produce more bright pixel than the other blue photon with lower frequency? One more thing on frequency. While CCD's have a range of wavelengths they respond too, they do not respond to all of these wavelengths equally well.
See page 5 of the following link: The QE is the percent of light that reaches the CCD that will end up being converted to photoelectrons.
The graph is labeled from 0. As you can see, the graph peaks in the nm range, which is the blue-green region, for a monochrome CCD. The colored lines represent the 3 different color filters of a bayer filter that come with the color chips.
The human eye is far harder to quantify a QE for, as vision is not just a mechanical process of detecting light and turning it into a value, but an extremely complicated process involving multiple receptors, timing of these receptors firing, and dozens if not hundreds of other things.
- Relationship of color and intensity to frequency and wavelength?
- How are frequency and wavelength of light related?
- Is there any relation between wavelength and brightness?
But don't quote me on that. I thought frequency defines color, that frequency is just another face of the wavelength and that they are always in constant relation.