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What is CMYK and Why is it used for Printing?

Jessica Sanchez

If you've ever had a project commercially printed, you've most likely heard the term "CMYK".  But what does CMYK mean and why is it important?

Let's discuss the definition of CMYK, how this color process works in commercial printing and why it is the dominant color model.

What is CMYK?

CMYK is an acronym for Cyan, Magenta, Yellow and Black.  CMYK refers to the 4 primary colors of pigment used in 4 Color Process Printing.   The CMYK color model also describes the full color printing process itself.  In full color printing, every image is color separated into Cyan, Magenta, Yellow and Black in specific dot patterns that vary in size and frequency to create a combination of ay color with a fraction of the ink.


CMYK is a subractive color spectrum.  This means that these inks mask colors on a lighter background (like white paper).  The CMYK ink subtracts the red, green and blue from white light and leaves the Cyan, Magenta, and Yellow.  Black is the absence of color.

The CMYK color model works by partially or entirely masking colors on the lighter surface (paper or substrate).  The ink reduces the light that would otherwise be reflected.

The RGB color model works the opposite.  RGB is an additive color spectrum.  When RGB colors overlap, the results are subtractive colors (cyan, magenta, yellow) RGB color model uses transmitted light.  Additive color models use light to display color, while subractive (CMYK) color models use reflected light.

RGB color space is primarily used on digital displays (computers, tablets, TVs, etc) and uses the light from the device to display the color.  The colors result from transmitted light.  When all spectrums from the RGB color space overlap, the result is white.

CMYK color space is primarily used for printed material and uses ink to display color.  The colors result from reflected light.  When all spectrums from the CMYK color space overlap, the result is black.

RGB will need to be converted to CMYK color space for printing

RGB Colors may look great on screen, but they will need to be converted to CMYK color space before supplying your art files to your printer.  Learn more about converting your art from RGB to CMYK here>>>>

CMYK "Halftones" and Understanding the Process

A halftone is simply a group of large and small dots that when viewed at a distance, have the appearance of continuous shades of gray or color in an image.  

Halftone printing is a reprographic technique of breaking up an image into a series of dots in order to reproduce the full tone and color range of a photograph or monotone art work.  This process simulates continuous tone imagery through the use of dots, varying in size and spacing.  This process also uses various line screens and frequencies to create various densities and a wide range of reproducible colors.  This line screen is also referred to as LPI (lines per inch).  The line screen is the frequency that will control the depth of the colors, the amount of dots.  For example, photorealisitc images have an optimal line screen of 65, while simple color images would have an optimal line screen of 35.  LPI (lines per inch) is NOT the same as DPI (dots per inch), which is another common printing term you've most likely heard as well.  Learn more about DPI and Image Resolution here>>>

The other factor involved in printing halftone images is what angle to output the dot pattern at.  The angle is very important in order for the image to look correct.  For example, if you have the incorrect angle and line screen combination, you will get a "Moiré" effect which makes the dot pattern appear like a checkerboad pattern and not a smooth image.  Learn more about Halftones , LPI and screen angles here>>>

Conclusion: CMYK Produces Superior Color in Printing

In conclusion, CMYK is the industry standard for printing because of the science behind the color space and the substrate.  Ink on paper must use the CMYK color space to acheive the optimum results by creating an unlimited number and shades of color.  CMYK will produce full, dark, rich and vibrant colors to bring your project on paper to life!