An explanation as to why you the colours seen on a computer screen will not match the colours printed.
You’re not alone if you find this baffling, it has confused some designers and marketers alike, but RGB and CMYK difference will have a huge impact if you’re designing for print. Here we explain the difference and why you should be aware of the two colour formats.
In brief – Colours are displayed on screen in (RGB) and are printed (CMYK). This along with different image resolutions, screen brightness and contrast can add many variables – the colour on screen cannot be relied upon and hence an RGB and CMYK difference.
Computer colour displays – RGB Colour format
Just as the colour on your television, computer screens display colours using a format called RGB. This stands for Red, Green, Blue and combined these are known as pixels or dots. The screen is filled with tiny little dots which when mixed in different intensities, form the desired colour. Combined on mass they create the required graphics using the RGB colour format in a transmissed light source.
Commercial colour printing and desktop printing – CMYK Colour format
Presses print colours using a format called CMYK. This stands for Cyan, Magenta, Yellow, Black. Just like a computer screen these colours are printed at different levels of intensity from 0% to 100%, so when combined create the desired colour seen by the eye in a reflective light source. We discuss more about understanding colour here and avoiding the pitfalls of Pantone and CMYK reproduction here.
Brightness and contrast of the screen
Adjusting both the brightness and constrast on screen will change the colours slightly. If two screens were put side by side and the same artwork was displayed, the chances are the artwork would look different on both screens. This is course depends on the make, model and to what extent the screens are calibrated.
Whilst some computer displays are more accurate than others, they will never be 100% accurate in displaying the correct pantone colours. Software and devices such as Pantones huey PRO can enhance accuracy in a professional environment.
Graphic and image resolution
Printing requires a certain number of dots to produce graphics clearly during printing, this is 300 dots per inch, known as a resolution of 300DPI. If a resolution is lower than 300DPI it will negatively imact the printing results.
To understand how this can affect your artwork can be demonstrated if you have ever taken a website graphic, enlarged this to cover an entire A4 page and printed this. The result is often what is known as pixilation. This is where the detail of the image is not great enough to print the desired graphic, resulting in a blurry looking image.
This is easily explained by understanding that a printer is trying to print more detail (300DPI) on to the sheet of paper, whereas the web image only has limited detail (likely to be 72DPI). Whilst you can enlarge the image there is not enough detail to fill this space with the missing dots required, when this is not possible the expanded image will appear blurry, hence the term pixilation.
To be confident of the accuracy about what you are seeing on screen it is worth considering speaking to your commercial printer about printed proofs. Office desktop printers are not calibrated to Pantone colours standards and are unable to print accurate results. For more about printed proofs prior to printing read our article here.