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 illustrationshttp://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 OPAQUE TRANSPARENT LIGHT PIGMENTS PIGMENTS/INKS
ADDITIVE RGB color of computerprimary colors Green monitors, television, andof LIGHT (approximately) human vision Yellow Cyan Red Blue Magenta
A computer monitor pixel is composed of 3 subpixels (each a tiny transistor) with red, green, and bluefilters. Through the careful control and variation of the voltage applied, the intensity of each subpixel canrange over 256 levels (black =0, white=255). Combining the subpixels produces a possible palette of16.8 million colors (256 shades of red x 256 shades of green x 256 shades of blue).
Color Modes in Adobe CS Applications Illustrator Photoshop Grayscale Bitmap RGB Grayscale HSB RGB CMYK HSB Web Safe RGB CMYK Lab Web Color
Color Spaces and Gamuts L*a*b L*a*bDevice-independent (L*a*b) and device-dependent (everything else)http://photo.net/digital-darkroom-forum/00QNAohttp://help.adobe.com/en_US/Acrobat/9.0/Standard/WSFC77A86E-F68E-4906-A42D-6EAF5AB4F675.htmlhttp://www.tasi.ac.uk/advice/creating/colour2.htmlhttp://forums.adobe.com/message/2997551
RGB vs CMYKRGB: colors of computer monitors; larger color gamut thanCMYK; colors appear brighter, more vibrantCMYK: colors of transparent inks in 4 process printing;smaller gamut; many RGB colors “out of gamut”, cannot beprinted in CMYK inks. RGB CMYK
RGB vs CMYKOrthodoxy: RGB images must be converted to CMYKprior to 4-process printing. Work in CMYK for printing.NO!: Work in RGB! Larger gamut, more flexibility.Consumer inkjet printers convert to CMYK automaticallyand do an excellent job (use as reference). Otherwise, useAdobe CS software to convert a copy or let the commercialpress do it for you. Adobe CS software gives “out ofgamut” 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" thats 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.