Yaa Colouring Perception Theory For Textiles

Color Perception Theory for Textiles

Kumaresan. S.
Dept of Textile Engineering
Anna University, Chennai, Tamilnadu, Bharat
Email: kumaresan.ss007@gmail.com

What is color ?
Color is something which makes the object to a greater extent than appealing, attractive as well as gives the pleasance of observation. color is defined as visual sensation arising from the stimulation of the retina of eye. Thus it is defined as psychophysical (the psychological answer to the physical stimulus). Color may bring dissimilar pregnant to the dissimilar people.

To chemist - It may survive a chemic chemical compound (Dye or Pigment).

To physicist - It is a scattering or absorption of lite or reflectance spectra of an object.

To physiologist - It is a measurable electrical activity of nerves.

To psychologist - It is a complex procedure inwards encephalon of interpreting the indicate of the nerve.

To creative individual as well as others - It is the agency to create the sensation inwards the heed of the observer.

With the consideration of textiles, color is a real desirable parameter of a textile product. In representative of technical textiles, color of the stuff is non necessary. Because it is solely made amongst functional characteristics for high surgical operation application. But inwards representative of wearing clothing production, color is a real crucial parameter. Because the consumers piece buying the stuff inwards the market, they are highly attracted past times the color of the stuff as good as the have got of the product.

The color of the textile production may varies amongst individual to individual as well as besides the source which is used to perceive the color. The original argue for the variation of color vision inwards human is trunk motors (physically balancing) as well as mentality (psychologically balancing) of the person. Then the color of the stuff varies nether the dissimilar sources. It is called metameric demeanour of the textile material. Also the color of the sample should survive matched amongst buyers sample was real difficult. There are numerous colouring stuff available for coloration of textiles. Now nosotros shall larn virtually regulation of perception of color inwards the human vision.

Perception of color involves a serial of events which are interdisciplinary inwards nature. Perception of color includes source of light, object that is illuminated as well as oculus as well as encephalon that perceive the color. It is clearly shown inwards the next figure.

Fig: Perception of color

The source of the lite is characterized past times its unloosen energy distributed at dissimilar wavelengths (i.e. spectral mightiness distribution of the lite source). The alteration of the incident lite depending upon the nature the colorant which is introduce inwards the object. Then the radiations reflected past times the object is received past times the eye. The radiant unloosen energy is absorbed past times the photosensitive pigments inwards the retina of eye. This gives ascent to nervus impulse which transmitted to the brain. The encephalon interprets the indicate of the nervus depending on the informations (data’s) stored inwards the memory. We shall forthwith regard each of these components of color viewing separately.

Source of Light:
Light is a shape of unloosen energy as well as its propagates inwards the shape of electromagnetic waves. Wavelength is of import feature of electromagnetic wave. Therefore the the waves at the dissimilar ranges are identified past times dissimilar names similar gama rays, X rays, UV rays, visible rays, IR rays. Only a small-scale constituent of the electromagnetic spectrum produces the sensation of vision. This constituent of the spectrum is called visible region. The wavelengths of the visible part varies from 380 to 750 nm.

Fig: Electromagnetic spectrum

The source of the lite is characterized past times its relative mightiness distribution at dissimilar wavelengths. The lite sources may survive incandescent lamp, fluorescent light as well as arc lamp. Spectral mightiness distribution of sources similar candle light, sunlight as well as incandescent lamps are continuous.

The measure sources are recommended past times CIE ( Commission International de L’Eclairage).This organization quantify the colors interms of mathematical numbers. The sources are called as measure illuminants A,B as well as C.

CIE illuminant Influenza A virus subtype H5N1 has color temperature of virtually 2854 K. its spectral mightiness distribution is similar to that unloosen energy radiated past times 100 watt tungston lamp.

CIE illuminant B has color temperature of virtually 2854 K. its spectral mightiness distribution is similar to that unloosen energy radiated past times noon daylight.

CIE illuminant C has color temperature of virtually 6500 K. its spectral mightiness distribution is similar to that unloosen energy radiated past times average daylight.

CIE defines the higher upwardly illuminants for visible attain of wavelength virtually 380 to 780 nm. But amongst the evolution of fluorescent colors as well as fluorescent whiting agent, it is necessary to hand measure illuminant for UV region. So that CIE defined the daylight illuminant D65. The color temperature of the D65 illuminant is 6500 K. The next figure volition shows the relative mightiness distribution of the CIE measure illuminants.

With the evolution of source technology, multifariousness of efficient fluorescent sources bring come upwardly into the marketplace seat as well as are widely used inwards the household as well as shops for lightings. These are mainly fluorescent sources having discontinuous spectral mightiness distribution. The manufacturers of garments as well as textiles, they would similar to asses their color of products nether these illuminants. CIE besides defines the fluorescent sources F1,F2 as well as F3 to enable to calculate matameric indices of whatever product.

Object:
The illuminating radiations are modified past times the physical processes such as transmission, absorption,reflection as well as scattering. The relative proportions of these processes depends on the characteristics of the material. When the emerging lite is same inwards the management of incident lite , it said to survive transmission. When the stuff absorbs lite it absorb all the spectral components except roughly color, thus that it appears roughly color. The absorption occur inwards the stuff depends on the concentration of the coloring thing inwards the material. In improver to the absorption, scattering may occur inwards the material. In scattering procedure lite travels inwards many management other than the incident direction. When sufficient scattering occurs, it said to survive diffuse reflection or transmission. The amount of lite scatters depends relative refractive index as well as particle size of colorants. When the lite is incident on the surface, roughly amount of lite may survive reflected from the surface. If the angle of incident is angle of reflection, thus it said to survive specular reflection. The reflection amongst varies angle is called diffused reflection. The amount of reflection depends on the nature of the colorants inwards the stuff as well as surface texture of the material.

The appearance of the object is characterized past times its spectral reflectance curve. The location of peaks spectral reflectance bend determines the hue of the object color. The object exhibits absorption peaks inwards the spectral reflectance bend at definite wavelength depending upon the color of the object. The spectral reflectance of achromatic colors( dark as well as white) do non exhibits whatever peaks. The spectral reflectance bend of achromatic as well as chromatic objects are shown inwards the below figure.

The reflectance of whatever object tin survive determined past times using the musical instrument called spectrophotometer. It gives a reflectance bend (spectrum) of an whatever object. The reflectance value varies from 0 to 1. The corresponding reflection percent lies betwixt 0 to 100.

Observer:
The mutual detector of lite as well as color is eye, nervus organization as well as brain. The focuses the ikon of the object on retina. The photosensitive detectors inwards retina are called as rods as well as cones from their shape. The rods solely uncovering the lite but it bring no mightiness to specify the color. The cones are responsible for color detection. There are 3 types of cones receptors inwards the retina. They are sensitive to lite at dissimilar attain of wavelengths. Three types of cones inwards the retina are

1. Red sensitive cones
2. Green sensitive cones
3. Blue sensitive cones.

The ultimate sensation of colors depends on the flat of stimulation of these 3 color receptors. If all the 3 cones are every bit stimulated, it gives sensation of grayness to white depending on the flat of stimulation.

The CIE recommends the measure observer information for color calculation. The measure observer is a individual who is physically as well as psychologically balanced. Influenza A virus subtype H5N1 describe of defining measure observer which may correspond the normal color vision of average human population is difficult. CIE defined the measure observer data. There are 2 types of measure observer information called as 2º as well as 10º observer data. 2º observer information were prepared using fovea part of human eye. In practise inwards visual assessment of color, 1 uses larger are of retinal surface. The construction of fovea as well as the environs of retina are different. Therefore CIE defined roughly other laid of information is called 10º observer data. These data’s defined past times using 10º champaign of view.

Color Mixing Theories:

Primary colors:
Red, yellowish as well as bluish are called primary colors. These colors cannot survive mixed or formed past times whatever combination of other colors. All other colors are derived from the primary colors.

Secondary colors:
Green, orangish as well as royal are called secondary colors. These colors are formed past times mixing of the primary colors.

Tertiary colors:
Yellow-orange, red-orange, red-purple, blue-purple, blue-green as well as yellow-green are called third colors. These colors are formed past times mixing of primary as well as secondary colors.

There are 2 types of color mixing namely additive as well as subtractive mixing.

Additive color mixing:
Additive color mixing occurs when 2 or to a greater extent than lights are added past times focusing them on the white screen. In additive color mixing, red, greenish as well as bluish are used as primaries to make dissimilar colors. The primary colors are selected are independent inwards the feel that mixture of 2 primary volition non make the other primary. The combination of dissimilar primaries produces dissimilar colors similar following,

Red + Green → yellowish

Green + Blue → cyan (blue-green)

Blue + Red → royal (magenta)

Red + Green + Blue → White

Subtractive color mixing:
Subtractive color mixing occurs when 1 or to a greater extent than spectral components are removed from the incident light. The removal of constituent of incident unloosen energy tin occur past times procedure of absorption or scattering. In absorption process, the lite unloosen energy is converted into a heat. When the subtraction is made past times absorption only, it said to survive uncomplicated subtractive mixing. When the lite is removed past times scattering as well as absorption, it said to survive complex subtractive color mixing. The subtractive primaries are obtained past times removing blue, greenish as well as cerise lite from the white light.
 

Conclusion :
The next parameters should regulation the perception of color.

Relative spectral mightiness ( defined past times CIE)

Standard observer information ( defined past times CIE)

Reflectance value for visible spectra ( given past times spectrophotometer)

By using these data’s nosotros should uncovering out the tristimulus values which may limited the color interms of mathematical numbers. These values are used inwards the color matching of sample to the target( buyer’s sample).

Limitations of tristimulus values:
From the tristimulus values nosotros may compare the lightness of the target as well as sample. But it should non hand whatever information virtually Hue as well as chroma.

You may besides like:

1. Basic Concepts of Colour Measurement
2. An Overview of Colour as well as Textile Dyes
3. Importance of Color inwards Textile
4. Application of Color as well as Light Theory inwards Textile Wet Processing (Dyeing) 

 

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