Find Your Color

http://colourco.de/


Color Gamuts and Color Spaces


Most devices we use are limited with regards to the gamut of colors they can reproduce.

Monitors and screens use light (RGB spectrum) while print devices use inks (CMYK spectrum).


gamut.gif
Various color spectrums


Visual, monitor (RGB), CMYK, and pantone spectrums
From http://dx.sheridan.com/advisor/cmyk_color.html




CMYK


Use CMYK for commercial printing jobs and printers using CMYK inks.

  • Cyan absorbs red and reflects back green and blue

  • Magenta absorbs green and reflects back red and blue

  • Yellow absorbs blue and reflects back red and green

  • Black added to keep from getting muddy brown colors



As you add ink you darken the color. Values go from 0% saturation to 100% saturation.

White
C = 0
M = 0
Y = 0
K = 0


Best Practices / Tips for Using CMYK for Print


1. DO NOT USE MORE THAN 280% saturation (total ink coverage) Too much saturation can cause the ink to smear when printed.

2. To darken a color, DO NOT just add black. Add the opposing color.

3. When creating CMYK swatch colors, keep as a process color. DO NOT make up your own spot colors unless you actually have that color ink to give to the printer.

4. Use a rich black swatch for all blacks to trap the potential white gaps between strokes and fills during printing.

Rich Black
C = 50
M = 50
Y = 50
K = 100

5. DO NOT use a stroke smaller than 0.25 pt (hairline stroke) or it might not be visible.



Industry Standard Spot Colors

Pantone
Focoltones
Toyo
Trumatch


Getting RGB Colors in Print


  • Yellow and Magenta = Red

  • Cyan and Yellow = Green

  • Cyan and Magenta = Blue

Note: These colors are not as bright as their RGB counter-parts in an RGB color space.

The RGB color swatch palette (RGBCMYK) colors and CMYK color swatch palette (RGBCMYK) colors on the left were created in the CMYK workspace. The ones on the right were taken from the same color swatch palettes in the RGB workspace.

Column 1 (right to left): Red, Green, Blue, Cyan, Magenta, Yellow, Black from the RGB color palette in the CMYK workspace.
Column 2: Red, Green, Blue, Cyan, Magenta, Yellow, Black from the CMYK color palette in the CMYK workspace.

Column 3: Red, Green, Blue, Cyan, Magenta, Yellow, Black from the RGB color palette in the RGB workspace.
Column 3: Red, Green, Blue, Cyan, Magenta, Yellow, Black from the CMYK color palette in the RGB workspace.

Note the CMYK colors remain pretty consistent from one workspace to another but the RGB colors differ dramatically. RGB swatch colors are brighter in the RGB color workspace. Keep in mind this is what the colors look like on a monitor. You need to print them out to see what they will look like on paper.

ColorSpaceColors.png
ColorSpaceColors-RGB.png

Illustrator Files for Print Comparison






RGB


Use for Web, film, screen presentations, and ink-jet printers.

RGB is the larger, more dynamic spectrum BUT there are a lot of colors that CANNOT BE PRINTED without special spot colors (neons, very bright colors, etc.)

Note:
RGB cyan IS NOT CMYK cyan.
RGB magenta IS NOT CMYK magenta.
RGB yellow IS NOT CMYK yellow.

RGB values (in the RGB color workspace) are brighter.


As you add color, you brighten the result. Values are in luminous levels from 0 (no light) to 255 (full on light).

White
R = 255
G = 255
B = 255





HSB


Hue - color

Saturation - color intensity

Brightness - amount of white (more white = brighter color)




Techniques to Reproduce Colors in Print


Colors and tones are represented in print using dot patterns. Two typical patterns are halftone and stochastic.


Halftone Dot Patterns


260px-Halftoning_introduction.svg.png
Halftone dot pattern versus continuous tone (contone) pattern


Halftone dot pattern versus a continuous tone (contone) pattern
http://en.wikipedia.org/wiki/Halftone

Halftone dot pattern is also known as an AM (Amplitude Modulation) screen. The dots are equally spaced. The size of the dots determines how dark the grays appear - larger dots look darker.

Most commercial printers use AM screening.

Best Practices Regarding Using Halftone


  • It takes more pixels per inch to print an AM dot pattern so resolution is critical.

  • Because halftone already uses a square pattern, printing images with patterns using AM screening can result in a Moirè pattern.

Stochastic Dot Patterns



screening.gif
Halftone versus Stochastic Screening


Halftone versus Stochastic Screening
http://www.rosco.com/US/gobos/process.cfm


Stochastic dot pattern is also known as an FM (Frequency Modulation) screen. The dots are always the same size and are randomly spaced. The number of dots in an area determines how dark the grays appear - more dots in an area look darker.

Some commercial printers use FM screening. Most ink-jet printers use FM screening.

Best Practices Regarding Using Stochastic


  • Stochastic typically produces a better continuous tone pattern than Halftone.

  • Because it does not take more pixels per inch to print an FM dot pattern, you can print images larger than the document resolution size.



Article on Conventional versus Stochastic Line Screening

http://www.arandellblog.com/index.php/arandell-prepress/stochastic-versus-conventional-line-screen-pros-cons-1/





Adjusting for Dot Gain


Adjust highlight (based upon output device) on each R, G, B adjustment layer.
  • Higher quality printers about 5% (242 out of 255)
  • Newsprint about 20% (205 to 210 out of 255)

Adjust shadow (based upon output device) on each R, G, B adjustment layer.
  • Higher quality printers about 95% (12 out of 255)
  • Newsprint about 80% (50 out of 255)

Adjust mid-tone on composite layer (125 out of 255)

Adjust upper quarter-tone to lighten up

Adjust lower quarter-tone to darken


Strip to Test for Dot Gain (Highlights)


Save and/or print the following graphic. Shades of gray range from 1% to 20%. The point at which the printer prints enough ink to show gray is the percentage you need to adjust for a truer representation of the colors in a printed version of an image.

CheckPrinterHighlightSetting.png
Percentage values of gray for a printer test


Photoshop File for Print




Color Tool Neenah Paper

ColorUnleashed.com




Deke's Hue Locator

http://www.graphic-design.com/Photoshop/color_cast/visible_color_spectrum.html

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