How CMYK works

The CMYK colour model is the colour printing process used by many print companies, and it refers to the way in which cyan, magenta, yellow and key (black) are aligned and mixed to create an entire range of colours. In essence, these four colours are the baseline for the spectrum; that being said, it is important for printing firms to use machinery that keeps them in perfect alignment in order to avoid errors in the printing process. Have you ever wondered how colour printing works? Many people never think about it, yet most of us print numerous pages every day. CMYK operates by masking the four colours on a light background, and it’s degree of masking that is performed which allows printers to produce full spectrum colours. The background is typically white; when the ink is printed it works to reduce its reflection/brightness.

It will be helpful to know the difference between the CMYK and RGB colour model in order to understand how it works; the latter is considered an additive colour model, in which red, green and blue (primary colours) are mixed to create secondary colours. CMYK, on the other hand, is considered a subtractive model in that it takes away from wavelengths of light when printed, i.e. the white backdrop. While the results are pretty much the same, it should be noted that print operators typically use CYMK over RGB when they need to produce deeper shades of black, unsaturated and darker colours. The subtractive model tends to be more cost-effective as well.

It will be helpful to know the difference between the CMYK and RGB colour model in order to understand how it works; the latter is considered an additive colour model, in which red, green and blue (primary colours) are mixed to create secondary colours. CMYK, on the other hand, is considered a subtractive model in that it takes away from wavelengths of light when printed, i.e. the white backdrop. While the results are pretty much the same, it should be noted that print operators typically use CYMK over RGB when they need to produce deeper shades of black, unsaturated and darker colours. The subtractive model tends to be more cost-effective as well.

Given that the colours used in the CMYK model work to reduce the reflection of the white background, how do they end up creating secondary colours? Print operators use a variety of screens and filters to control the degree of separation, and most companies in the industry do this via digital software (in contrast to the traditional use of photographic film which is more costly and time-consuming). The result is four distinct images that are transferred to printing plates; when finally printed onto paper, the secondary colours are created. In order to avoid errors in the printing process, operators need to maintain the proper total area coverage (TAC) of the paper or object. This is the total value of the CMYK inks and it is generally capped at 300%. Listed below are some of the benefits of using this model vs. additive types like RGB.

• The use of black allows operators to clearly print fine details without blurring, which can be difficult to do with additive models when working with certain font types.
• CMYK prevents ink bleeding, as the presence of black prevents the cyan, magenta and yellow process colours from fully saturating the printed surface. It consequently decreases the drying time.
• CMYK is cost-effective; black ink is not as expensive.