The Dynamics of Color

MCJ 312 GRAPHIC DESIGNLijie Zhou

Understanding electronic color

Pixel: Computer images (Raster graphics) are composed of individual dotsThe more pixels, the better the resolution and clarity of image.

A 24-bit color system (RGB):Bit: a basic unit of information in digital communication

Two value: 0 or 1Bit, KB (K), MB (M), GB (G)

Each pixel is represented by 24 bits of color information8 for red; 8 for green, and 8 for blue256 possible values for each of the RGBMore than 16.7million colors

Color ModelsRGB:

Light-based color source (monitor)At a low intensity: R+G+B=whiteR+G=Yellow; B+G=Cyan; R+B=magenta Each pixel contains three small light sources (different values of R+G+B)Example: a rich warm red: R=255, G=0; B=0

Color ModelsCMYK

Three primary-color printing inks (CMY)Black (K) ink is used to complement the other three colorsEqual amount of C+M+Y=blackExample: Warm red color=C(0%)+M (100%)+Y(100%)+K (0%)Nature grey=C(50%)+M (40%)+Y (40%)

Color ModelsHSL

Hue(H), Saturation(S), Lightness (L)The closest to the way mixed pigment color in painting and drawing

Color Gamuts:Visual color range of a color model is a gamutGamut of eyes> gamut of RGB> gamut of CMYK

Color in printingDesigner’s use of color must be:

Creative AppropriatePractical Printable

Tint screensMixed pigment: White + Black=Grey; Red + White=Light Pink; Blue + Yellow= GreenTine screens: Available in gradients from 10%-90%The value scale of tint screen is similar to a value scale mixed by an combining pigments

Why are the colors never right?

Basic differences between printers and printing processes.

CMYK with inks vs. RGB with light sources (different color range)

Differences between two devices suing the same color system

Example: laser printer vs. inkjet printer Later printer: ink powerInkject pritner Liquid ink

Differences between two pieces of the same kind of equipment.

Color management system that can measure and indicate colors precisely, independent of the device the color is displayed on

ColorMunki

RGB Color StandardAdobe RGB:

wider color space than ColorMatch RGBThe most commonly used RGB standard in professional graphic production

ECI RGBNew RGB standard developed by the European Color InitiativeThe same color space as Adobe RGB

sRGBsRGB is a standard supported by Hewlett-Packard and MicrosoftBased on the HDTV standardOrdinary PC monitor can displayColor space is much smaller than most of RGB standard

Apple RGBThe color space is not much larger than sRGBNot suitable for graphic production

ColorMatch RGBBased on the RGB color space of a Radius RessView monitor (professional graphic design monitor)Relatviely small color space

Wide Gamut RGBHaving a large color space13% lies outside of the visible areaHaving problems when converting from RGB to CMYK since too many colors

CIE RGBOld RGB color space Hardly use anymore

NTSCOld RGB color space sued for video. Relatively large color gamutThe North American standard for TV transmissions

PAL/SECAMStandard RGB color space for TV transmissions in EuropeRelatively small color range