Elements 7

Color, Value and Hue

GREEN. Positive - Harmony, balance, refreshment, universal love, rest, restoration, reassurance, environmental awareness, equilibrium, peace.Negative - Boredom, stagnation, blandness, enervation.

Green strikes the eye in such a way as to require no adjustment whatever and is, therefore, restful. Being in the centre of the spectrum, it is the color of balance - a more important concept than many people realise. When the composition contains plenty of green, this could be associated with the presence of water, and lesser danger of famine, so we are unconsciously reassured on a primitive level. Negatively, it can indicate stagnation, wilderness and, incorrectly used, will be perceived as being too bland.


BLUE. Positive - Intelligence, communication, trust, efficiency, serenity, duty, logic, coolness, reflection, calm.Negative - Coldness, aloofness, lack of emotion, unfriendliness.

Blue is considered to be the color of the mind and is essentially soothing; it affects us mentally, rather than the physical reactionwhich is prominent in case of red. Strong blues will stimulate clear thought and lighter, soft blues will calm the mind and aid concentration. Consequently it is serene and mentally calming. It is the color of clear communication and non-bias. Blue objects do not appear to be as close to us as red ones, they recede. It is more related to non-life, and non-food items. Time and again in research, blue is the world's favorite color. Associated with male gender, and smartness. However, it can be perceived as cold, unemotional and unfriendly. Fluorescent shades could be perceived as heavenly, cosmic.

VIOLET. Positive - Spiritual awareness, containment, vision, luxury, authenticity, truth, quality.Negative - Introversion, decadence, suppression, inferiority.

The shortest wavelength is violet, often described as purple. It takes awareness to a higher level of thought, even into the realms of spiritual values. It is highly introvert and encourages deep contemplation, or meditation. It has associations with royalty and usually could communicate the finest possible quality. Being the last visible wavelength before the ultra-violet ray, it has associations with time and space and the cosmos. Excessive use of purple can bring about too much introspection and the wrong tone or combination could communicate something cheap and nasty, faster than any other color.


PINK. Positive - Physical tranquility, nurture, warmth, femininity, love, sensuality, survival of the species.Negative - Inhibition, emotional claustrophobia, emasculation, physical weakness.

Being a tint of red, pink also affects us physically, but it soothes, rather than stimulates. (Interestingly, red is the only color that has an entirely separate name for its tints. Tints of blue, green, yellow, etc. are simply called light blue, light green etc). Pink is a powerful color, psychologically. It represents the feminine principle, and survival of the species; it is nurturing and physically soothing. Too much pink is physically draining and can be somewhat emasculating.



Market research on color is also done to establish color trends.

Color forecasting is accomplished by surveying consumer preferences and other indicators of changes in taste. Colorforecasting firms then issue projections defining palettes of colorsthat can be expected to rise, fall, or maintain popularity in coming seasons. The design industries then develop their new lines with these projections in mind.

Some major companies employ their own color forecasters to research and project color trends for their industry.

On the whole, color trends change more rapidly for fashion than for other design industries, probably because changes in other industries entail a more serious financial investment.

Color, Value and HueLuminance / Luminosity

Are terms used to refer to the brightness of an image.

Luminosity is a measure of light sources, whereas Luminance is a measure of things that are lit, rather than emitting light. Luminance is measure of the amount of light reflected from a hue. Those hues with a high content of white have a higher luminance value.

Luma - Black & White information (Value detail)

Chroma - Color information (Saturation detail)

Human vision is more sensitive to Luma (black & white) detail than Chroma.

Color, Value and HueColor theory is based on the properties of the human visual system (HVS), therefore, the scientific notions involved always relate to the way humans perceive color.

The work of Thomas Young, J. C. Maxwell and H. von Helmholtz (19th Century) established the principles of the mathematical theory of color. Maxwell is credited with the foundation of the Trichromatic theory, which states that any color can be obtained by combining, in various proportions, three conveniently chosen primary colors.

The choice of primary colors is what links the theory with the physiology of the HVS. The eye's light sensor, the retina, is composed of two types of light sensitive cells.

Rods, the cells of the first type are sensitive to light intensity and are what we use to perceive shapes and contours. Cone cells are responsible for color vision. There are three subtypes of cones, the difference between them being the wavelength selectivity, or primary color for which they are tuned.

Color, Value and Hue The cones for short (S), medium (M) and long (L) wavelengths are

most sensitive to blue (B), green (G) and red (R) respectively.

The sensitivity of the respective cones to red, green and blue is not equal. The quantity of light necessary in order to produce the same sensation of intensity is different for S, M and L cones.

R, G and B were chosen as the primary colors as these three best fit the receptors in our eyes and thus, when mixed, produce the whole range of visible colors. Any three colors can be used as primaries, but by not choosing them conveniently', the range of colors that may be obtained by mixing is limited.

Color, Value and HueColorimetric systems

The color matching test produces a description of colors visible to humans in terms of the proportion of the R, G and B primaries necessary in order to obtain the same visual sensation. Several colorimetric systems, ways of classifying and identifying colors by specific attributes, have been developed. The chromaticity diagramdeveloped in 1931 by the International Commission for the Illumination (CIE Comission Internationale pour l'Eclairage) is still a widely used tool when it comes to color spaces.

By using the values from the color matching diagram it is possible to plot into three-dimensional space the position of all the colors in the spectrum, having the amount of red (R), green (G) and blue (B) on the three axes respectively. The origin (O) is the black point where there is no red, no green and no blue.

Color, Value and HueCIE 1931 chromaticity diagram

The point where x = y = 1/3 is called the reference white (E white).

The coordinates x and y are artificial. They do not represent real colors in themselves.

The CIE 1931 chromaticity diagram represents all visible colors at full luminance.

It is part of the CIE-XYZ color space. Think of the diagram as the top slice of the CIE-XYZ color space. Other slices have colors with the same hue and saturation, but darker. These other slices are stacked on the z axis.

Color, Value and HueMacAdam ellipses

For any given color in the CIE-XYZ space, there is an area (MacAdamellipse) surrounding that particular color containing colors that are perceived as being the same as the original color. Since the human visual system is sensitive in different degrees to red, green and blue, the MacAdam ellipses vary in shape and area depending on the location in the color space.

Color, Value and HueA color space is the sum of all the colors that can be represented starting from a set of primaries and a blending (color mixing) rule. It is a mathematical description of how colors can be uniquely identified by a suite of values called color components. The CIE-XYZ colorimetric system is in itself a color space (the color space of human color vision). All color spaces within the CIE-XYZ are three dimensional spaces and the horseshoe diagram is a slice in the CIE-XYZ color space for maximum z (maximum brightness).

To create a color space (a subspace) in the CIE-XYZ, any number of primaries can be used. Within the chromaticity (horseshoe) diagram, a color space would look like a polygon with the primaries as its tips. The area of the polygon for a particular color space is called the gamut of that space. The bigger the gamut, the larger the number of colors contained.

Color, Value and HueRGB color spaces

Color, Value and HueCMYK

Subtractive mixing uses mainly cyan, magenta and yellow as primaries and is generally used for white media (i.e. printing).

CMY color spaces generally have a smaller gamut than the sRGBcolor space, particularly because that they do not contain very dark saturated colors.

Subtracting fully saturated C, M and Y from white at the same time does not create black. This is the reason black is usually added as a primary. It is abbreviated K from key'.

A serious problem arising when converting from RGB to CMYK (which happens whenever you print something digital) is represented by the fact that, generally speaking, there are colors in RGB that are not present in CMYK and vice versa.

Color, Value and HueWhen using the colorimetric systems and the color spaces defined within it, one can identify a color by its coordinates (or in other words by the amounts of each primary that need to be mixed, additively or subtractively, to obtain that particular color).

Other ways of identifying a color can be devised that do not use primary colors to describe the reference color space. But since the visible colors are fundamentally the same, these alternative color spaces are in fact mathematical transformations of the CIEXYZ.

Color, Value and HueColors are identified by their characteristics. These are:

Hue, the essential quality which differentiates colors based on difference in EM wavelength.

Luminance; allows classification in relation with an achromatic (grey) scale we say that the color is light or dark.

Saturation or purity. The pure colors are the colors found in the spectrum (and on the edge of the chromaticity diagram).

Color, Value and HueHSL and HSV the non-identical twins of color models

HSL (Hue, Saturation, Luminance) and HSV (Hue, Saturation, Value) color models are very similar. These are both three-dimensional spaces employing the hue wheel' as a common element. This hue wheel or disk has as its border a circle containing all the pure colors (or hues) of the CIE chromaticity diagram. Hue is described by the angle on this circle, with zero (and 360) degrees corresponding to pure red, as in the rough representation below.

Color, Value and HueSaturation is described by the distance from the center of the circle, which by definition has zero saturation. The colors of maximum saturations are on the circle bordering the hues disk.

Color, Value and HueIn the HSV (also called HSB, B for brightness) color system, the colors of maximum saturation (on the edge of the hue disk) are not necessarily pure (spectral colors). The HSV is an alternate representation of a given RGB color space, and the saturated colorsin HSV are the colors bordering the corresponding RGB triangle in the chromaticity diagram.

For this reason, the HSV color system is said to be device dependent, meaning that it is not an absolute colorimetric space, but relative to the gamut of the RGB color space it describes.

The third coordinate in HSV (or HSB) is the value or brightness; black has zero brightness. Starting from the hues disk one can imagine the HSV space as a collection of hues circles with varying color value, one on top of the other and of the same size (creating a cylinder) or of sizes diminishing with value (a cone).

Color, Value and Hue While a cone is more intuitive, as all colors converge to black for

zero value, the cylinder shape is more correct as a mathematical representation.

Color, Value and HueThe HSL, also named HLS and HIS (I for intensity, which is the same as lightness) is a similar representation to HSV, in that they are both nonlinear transformations (alternative mapping systems) of a particular RGB color space (this fact making them relative and not absolute ways of measuring color). The other similarity is that they both employ the hues wheel.

Good representations of HSL are a sphere or a double cone.

Color, Value and HueIn the HSV cone, the number of colors decreased with value.

In the HSL cone, they still do, but the maximum color range is not for maximum lightness but for 50% lightness. While HSV has a large number of colors with maximum value, HSL only has one - white.

HSV

HSL

Color, Value and Hue Both HSL and HSV are more intuitive ways of representing the

RGB color space. It is debatable which of the two represents a description of color more suitable to humans, but HSL seems more adequate due to the fact that it creates truly independent representations for saturation and lightness.

In HSV 100% lightness corresponds, among others to very saturated colors making it unnatural to think about, say, bright red as a very light color, which is not the case in HSL.

On the other hand, HSL describes a lot of very light colors as fully saturated, which again contradicts the way we normally refer to color, making HSV a better system in this respect.

The two spaces have a different way of defining the brightness (and to some extent saturation) and the same number for value and lightness yields different results.

Color, Value and HueLab is the three dimensional color space in which the coordinates that describe a color are L (color lightness), a (position on the green-red axis) and b (position on the blue-yellow axis). This system was proposed by Hunter in 1948 and is yet another transformation of the CIEXYZ colorimetric system.

Frequently Lab is also used to describe the L*a*b* color space (1976 CIE L*a*b* or CIELAB) similar to the Hunter Lab. L* represents lightness and a* and b* are similar to a and b, the main difference being the way coefficients are computed.

The notation Lab in graphics software almost always represents the CIELAB color space.

Color, Value and HueLab is derived from the chromaticity (horseshoe) diagram by first changing the x and y axes to a and b, like in the diagram below. A negative a (or a*) value indicates a greenish hue while a positive ameans a magenta/reddish one. On the b (b*) axis, negative values stand for blue and positive for yellow. A value of 0 for L* is equivalent to black and L* = 100 describes white.

Color, Value and HueA slice of CIELAB in the ab plane for a given L is not rectangular.

This means there are values of a and b for which no real color exists. For different values of L, the representation in the ab plane changes. The figure below shows a slice in the CIELAB color space for L=65.

Color, Value and Hue CIELAB and CIEXYZ are far wider than the gamut of any

presentation medium.

The greatest advantage of CIELAB as a tool for representing and characterizing color over CIEXYZ is its greater uniformity; colors values on the three axes are distributed more closely and more linearly with respect to the human perception of color.

The CIEXYZ diagram is not considered appropriate because of its being highly nonlinear and quite deceiving in the representation of color distance.

Color, Value and HueMODIFYING HUES

Hexadecimal values are used in coding colors for computing systems to understand the color combination. Increasing or decreasing the individual digits of the hue's hexadecimal number will provide a variation in your selected color.

8 bit color system - the first two digits designate the Red value, the next two the Green, and the last two are Blue values. The lowest value that can be given to one of the light sources is 0 (hex #00). The highest value is 255 (hex #FF).

Lowest to highest: 0 1 2 3 4 5 6 7 8 9 A B C D E F

Color, Value and Hue8 bit color system, the combination of Red, Green, and Blue values from 0 to 255, gives more than 16 million different colors (256 x 256 x 256).

Color Color HEX Color RGB

#000000 rgb(0,0,0)

#FF0000 rgb(255,0,0)

#00FF00 rgb(0,255,0)

#0000FF rgb(0,0,255)

#FFFF00 rgb(255,255,0)

#00FFFF rgb(0,255,255)

#FF00FF rgb(255,0,255)

#C0C0C0 rgb(192,192,192)

#FFFFFF rgb(255,255,255)

Color, Value and HueIf Blue is gradually added to a yellow, mixed from red and green, the yellow goes through steps of decreasing purity, each "less chromatic.

Color, Value and HueIf all three color components are reduced simultaneously -- while retaining their mixing ratio -- the HUE remains unchanged. The color decreases in brightness.

If the components of all three primary colors are reduced to zero, the resulting color will be black. Like white, black has a saturation level of zero.

Color, Value and HueMuted colors are less saturated (vivid) and more natural. You get these in hexadecimal by adding a touch of two other two primaries to your main primary color, and reducing the value for that main primary.

Elements 7

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