Expert: Huma Riaz - 5/11/2005

Question
Hi Huma,
Could you tell me why the formula of CMYK seperation has been created for print, instead of RGB? Is there any specific advantage of using CMYK? Thanks.....

Answer
Dear Maani,

The answer is Yes! Let me tell you the basics of colors, it will be helpful to you to understand the reason afterwards


R G B   C O L O R :

"RGB" refers to the colors of light that mix to create colors. There are three basic colors of light - red, green and blue. When combined, they create an entire rainbow of colors, either by reflecting off, surfaces or by shining onto surfaces.

In design, RGB color is only used in website design and other designs that are only meant to be seen on your screen (software user interfaces, HTML email, PowerPoint presentations, and TV or movie graphics).

If you send a design to be printed, or print a design that has been created in the RGB color space on your home printer, the printout may not match what you see on the screen - RGB colors on the screen tend to be brighter than what is printed on paper. This is because the colors onscreen are created with light, which adds brightness of its own to the colors. When printing on paper, the light is taken out of the equation. The other reason for this is that an RGB color can be "out of gamut" for CMYK printing, meaning that some of the colors cannot be replicated with printing inks.

C M Y K   C O L O R :

CMYK color is also known as four-color printing, full-color printing, or process color printing.

CMYK color refers to a certain type of printing process. In CMYK printing, cyan, magenta, yellow, and black (the "K") inks are printed on the paper as tiny dots (referred to as a "screen" or "line screen"). These dots are so tiny that when they combine visually, they create a rainbow of colors.

This process is used in projects where printing the full range of color is required - in projects with full-color photography or when more than three colors overall are used in the design.

For the production of CMYK printing, digital printing is a more economical choice than full-color press printing. However, in digital printing, the types, colors, and thicknesses of paper available are often limited, based on the printing machine's specifications and capabilities.

The accuracy limitations of CMYK printing are that the results between different printing methods - digital printing versus press printing - can vary, sometimes greatly, depending on the printer's range, how it is calibrated, and the particular color you are trying to print. Even the results from different digital printers or presses can vary, so color accuracy may be an issue, particularly if you're printing items at different times or with different printers.

There are also colors that cannot be reproduced using the CMYK process - such as metallics, and very bright colors. To expand the color range, additional colors can be added to the mix to increase the range, for six- or seven-color printing. Alternatively, Pantone colors can be used to increase the range - going to five-color (or more) printing to get the color accuracy you need.




Feel Free to ask anything further


Huma Riaz
Location: Karachi-Pakistan