CMYK Versus RGB

• GROUP MEMBERS

1. Asim Hassan

Why use color?

• Color adds information that is often difficult to describe with words

• Color adds a sense of beauty and excitement otherwise hard to capture

But. . .

• Color illustrations require time, talent, and planning

• Color is more difficult to reproduce accurately in print, but more easily in digital media

• Color is expensive to print, except in large press runs; cost often borne by scientist

• Natural color• Symbolic color• Design color

Natural color• Captures the true

color of the specimen

• Most common use of color

• Watercolor, gouache, acrylic paints, colored pencil, mixed media/computer

Symbolic color• Use of standard colors

to portray different structures (e.g., red arteries, blue veins, yellow

nerves)• Often used in medical

and/or instructional illustrations

http://catalog.nucleusinc.com/nucleusindex.php?

Design color

• Color is used as part of the overall design to communicate information quickly, precisely, and noticeably

Color Theory

http://www.diycalculator.com/sp-cvision.shtml

Primary colors

• Irreducible components of color• Combinations of the 3 primaries produce

entire (infinite) spectrum of color

LIGHTOPAQUEPIGMENTS

TRANSPARENTPIGMENTS/INKS

ADDITIVE primary colors of LIGHT

Green

Red Blue

Yellow

Magenta

Cyan

RGB color of computer monitors, television, and (approximately) human vision

A computer monitor pixel is composed of 3 subpixels (each a tiny transistor) with red, green, and blue filters. Through the careful control and variation of the voltage applied, the intensity of each subpixel can range over 256 levels (black =0, white=255). Combining the subpixels produces a possible palette of 16.8 million colors (256 shades of red x 256 shades of green x 256 shades of blue).

SUBTRACTIVE primary colors of pigments

Yellow

Red Blue

Orange

Violet

Green

SUBTRACTIVE primary colors of OPAQUE PIGMENTS

Yellow

Magenta Cyan

Red

Blue

Green

SUBTRACTIVE primary colors of TRANSPARENT PIGMENTS/INKS

CMYK color of printing

ADDITIVE mixture involves the addition of spectral components (light)

SUBTRACTIVE mixture involves the absorption (or subtraction) of spectral components (pigments and dyes)

Additive and subtractive colors areCOMPLEMENTARY

G

B

RC

Y

M

Yellow

Red Blue

Subtractive primary colors(pigments)

Primary

Yellow

Red Blue

Orange Green

Violet

Secondary

Yellow

Red Blue

Orange Green

Violet

Yellow-orange Yellow-green

Red-orange Blue-green

Red-violet Blue-violet

Tertiary

Yellow

Red Blue

Orange Green

Violet

Yellow-orange Yellow-green

Red-orange Blue-green

Red-violet Blue-violet

Color Wheel

Rules of Harmony

Monochromatic

Analogous

Complementary

Splitcomplementary

Analogouscomplementary

Doublecomplementarytetradic

Triadic

Tetradic

See the “Color Guide,” “Color Picker,” “Edit Colors” in Adobe Creative Suites

Qualities of color

• Hue (the named color) • Saturation (chroma or tone)• Brightness (intensity or value)

• Temperature • Transparency & opacity

Yellow

Red Blue

Orange Green

Violet

Hue

Saturation

white

Brightness

black

Hue, saturation, brightness spectrum

http://livedocs.adobe.com/en_US/Photoshop/10.0/WSAAFD9CC8-831E-4593-8694-B39919F72A26.html

The “Color Picker” in Adobe Creative Suites

HueSaturation

Brig

htne

ss

Warm Cool

Temperature

Transparency Opacity

Illustrator Photoshop

GrayscaleRGBHSBCMYKWeb Safe RGB

BitmapGrayscaleRGBHSBCMYKLabWeb Color

Color Modes in Adobe CS Applications

Color Spaces and Gamuts

Device-independent (L*a*b) and device-dependent (everything else)http://photo.net/digital-darkroom-forum/00QNAo

http://help.adobe.com/en_US/Acrobat/9.0/Standard/WSFC77A86E-F68E-4906-A42D-6EAF5AB4F675.html

http://www.tasi.ac.uk/advice/creating/colour2.html

http://forums.adobe.com/message/2997551

L*a*b

L*a*b

RGB vs CMYK

RGB: colors of computer monitors; larger color gamut than CMYK; colors appear brighter, more vibrant

CMYK: colors of transparent inks in 4 process printing;smaller gamut; many RGB colors “out of gamut”, cannot be printed in CMYK inks.

RGB CMYK

RGB vs CMYK

Orthodoxy: RGB images must be converted to CMYK prior to 4-process printing. Work in CMYK for printing.

NO!: Work in RGB! Larger gamut, more flexibility. Consumer inkjet printers convert to CMYK automatically and do an excellent job (use as reference). Otherwise, use Adobe CS software to convert a copy or let the commercial press do it for you. Adobe CS software gives “out of gamut” warnings when working in RGB.

RGB

• Red-Green-Blue are the primary colors as they are defined by light. This is the "color space" you see on your monitor or television. Your computer automatically converts documents to cmyk when it prints to your inkjet or laser printer, but your colors will be less vibrant than you see on your computer screen. Using RGB creates problems when sending a job to a commercial printer.

CMYK

• Cyan-Magenta-Yellow-blacK are the primary colors as they are defined by printing inks which are made up of dyes and pigments. This is the "color space" that's used by commercial printers. Dyes and pigments do not produce as wide a range of colors as light so there is often an unwanted color shift and the colors will be more muted than they are on your monitor.

Most full color printing is accomplished using only these 4 colors. Sometimes a "spot" color — a clear varnish and/or a PMS (Pantone Matching System) color, which is a specific premixed color — will be added. To see an approximation on your monitor of the colors as they will be printed, you need to prepare your file using CMYK. Sometimes your program will ask if you are printing on "coated" (glossy or matte) or "uncoated" paper: Each accepts the inks differently so it helps to know the end product.

Red-Yellow-Blue

• These are the primary colors I first learned about when painting in oils and watercolors and, since paints are pigments and dyes, correspond to magenta (red), yellow, and cyan (blue).

The graphic shows the Visible Spectrum. Within that range is the RGB Gamut (Color Space) and the CMYK Gamut (Color Space).

This shows the direct comparison of the RGB Color Space and the CMYK Color

Space.

CMYK And its tones

RGB AND ITS TONES