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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• 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
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).
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)
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
Qualities of color
• Hue (the named color) • Saturation (chroma or tone)• Brightness (intensity or value)
• Temperature • Transparency & opacity
Hue, saturation, brightness spectrum
http://livedocs.adobe.com/en_US/Photoshop/10.0/WSAAFD9CC8-831E-4593-8694-B39919F72A26.html
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).