RGB on-screen & CMYK to print
There are two main ways to mix color - RGB & CMYK. Their differences can sometimes make it difficult to get the colors in the final product to look the way we want.
When supplying digital files for full color printing, it is important for us to supply images and graphics in the CMYK mode in order to print properly. Many software programs give you the choice to work in either the RGB or CMYK mode.
RGB stands for Red, Green and Blue which are the primary colors of light. Computer monitors emit color as RGB light. Most desktop scanners, digital cameras, and video capture systems save files as RGB.
Whereas monitors emit light, inked paper absorbs or reflects specific wavelengths. Cyan, magenta and yellow are "subtractive colors" - if you print cyan, magenta and yellow inks on paper, they ought to absorb all the light shown on them. What we see will be black!
Unlike the shades of colors in CMYK, which are varied using dots, RGB color shades are varied by using levels of brightness from the electronic source: a cathode ray tube (CRT), a liquid crystal diode (LCD), or from another electronic methods. Also, unlike the percentage of dots in print that comprise 100% offering 100 variations, there are 256 (0 to 255) shades or levels of brightness for on-screen color that generate 16,777,216 (256 x 256 x 256) color possibilities. Setting each RGB color to 255 will generate white and setting each to 0 leaves black.
On-screen color is RGB and print is CMYK. In effect, the two are opposites since again, one is subtractive color (CMYK) and the other is additive color (RGB) - combine red, green and blue light, and you get white light. Like monitors, printing inks also produce a color gamut that is only a subset of the visible spectrum, although the range is not the same for both.
An image that is in RGB mode is optimized for display on a computer monitor. RGB files will even look good when printed on many of the desktop color printers on the market today. However, they will not separate properly when made into film, and the resulting full printing job will not look the way you expect it to look.
In order to reproduce that very same image using ink on paper, it must be converted to the "CMYK" color mode.
Unfortunately not all colors in the RGB spectrum can be replicated in CMYK. Such colors are said to be "out of the CMYK color gamut". When converting from RGB mode to CMYK mode, software programs get as close to original color as possible. Some colors convert very well whereas others do not. Consequently, the same art displayed on a computer monitor may not match to that printed in a publication.
Some printers prefer digital art files be supplied in the RGB color space with ICC profiles attached. Images can then be converted to the CMYK color space by the printer using color management methods that honor profiles if present; this helps preserve the best possible detail and vibrancy.
Some printers may prefer your files be delivered in RGB with ICC profiles attached, as this allows the printer to use color management methods when converting to CMYK. Other printers may prefer your files in the CMYK mode, as this is the mode required for the printing process. If an RGB file is submitted, it must be converted to CMYK for print.
In practice, printing inks contain impurities that prevent them from absorbing light perfectly. They do a pretty good job with light colors, but when you add them all together, they produce a murky brown rather than black. The combined value of all CMYK inks for a particular area or object cannot exceed a specified amount, or ink may not transfer effectively and printed sheets may not dry properly. In order to get decent dark colors, black ink is added in increasing proportions, as the color gets darker and darker.
When supplying digital files for full color printing, it is important for us to supply images and graphics in the CMYK mode in order to print properly. Many software programs give you the choice to work in either the RGB or CMYK mode.
RGB stands for Red, Green and Blue which are the primary colors of light. Computer monitors emit color as RGB light. Most desktop scanners, digital cameras, and video capture systems save files as RGB.
Whereas monitors emit light, inked paper absorbs or reflects specific wavelengths. Cyan, magenta and yellow are "subtractive colors" - if you print cyan, magenta and yellow inks on paper, they ought to absorb all the light shown on them. What we see will be black!
Unlike the shades of colors in CMYK, which are varied using dots, RGB color shades are varied by using levels of brightness from the electronic source: a cathode ray tube (CRT), a liquid crystal diode (LCD), or from another electronic methods. Also, unlike the percentage of dots in print that comprise 100% offering 100 variations, there are 256 (0 to 255) shades or levels of brightness for on-screen color that generate 16,777,216 (256 x 256 x 256) color possibilities. Setting each RGB color to 255 will generate white and setting each to 0 leaves black.
On-screen color is RGB and print is CMYK. In effect, the two are opposites since again, one is subtractive color (CMYK) and the other is additive color (RGB) - combine red, green and blue light, and you get white light. Like monitors, printing inks also produce a color gamut that is only a subset of the visible spectrum, although the range is not the same for both.
An image that is in RGB mode is optimized for display on a computer monitor. RGB files will even look good when printed on many of the desktop color printers on the market today. However, they will not separate properly when made into film, and the resulting full printing job will not look the way you expect it to look.
In order to reproduce that very same image using ink on paper, it must be converted to the "CMYK" color mode.
Unfortunately not all colors in the RGB spectrum can be replicated in CMYK. Such colors are said to be "out of the CMYK color gamut". When converting from RGB mode to CMYK mode, software programs get as close to original color as possible. Some colors convert very well whereas others do not. Consequently, the same art displayed on a computer monitor may not match to that printed in a publication.
Some printers prefer digital art files be supplied in the RGB color space with ICC profiles attached. Images can then be converted to the CMYK color space by the printer using color management methods that honor profiles if present; this helps preserve the best possible detail and vibrancy.
Some printers may prefer your files be delivered in RGB with ICC profiles attached, as this allows the printer to use color management methods when converting to CMYK. Other printers may prefer your files in the CMYK mode, as this is the mode required for the printing process. If an RGB file is submitted, it must be converted to CMYK for print.
In practice, printing inks contain impurities that prevent them from absorbing light perfectly. They do a pretty good job with light colors, but when you add them all together, they produce a murky brown rather than black. The combined value of all CMYK inks for a particular area or object cannot exceed a specified amount, or ink may not transfer effectively and printed sheets may not dry properly. In order to get decent dark colors, black ink is added in increasing proportions, as the color gets darker and darker.
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