Why are the colours printed different from those on the monitor?
There will always be a difference between the two devices due to the fact that they use different technologies to represent colours.
Neither a printer nor a monitor is capable of reproducing the full range of colours visible to the human eye. Each device is restricted to a certain range of colours. In addition to this, a printer cannot reproduce all of the colours displayed on a monitor and vice versa.
A monitor can display very vivid colour such as intense Reds and Blues which cannot be easily produced on a printer. Similarly, there are certain colours, Yellows for example, that can be printed but cannot be displayed accurately on a monitor. This disparity between monitors and printers is often the main reason that printed colours do not match the colours displayed on screen.
RGB v CMYK
It is almost impossible to replicate the exact colours you see on your monitor with those that you print as they use two entirely different colour models.
BLACK Toner (K toner) is added into the CMYK process because, while in theory black can be created by combining Cyan, Magenta and Yellow, in reality the end result of this combination has a tinge to it that doesn’t give the effect of a pure black.
As you can see from the animations above:
Yellow: To create the colour Yellow, your monitor has to transmit the colours Red and Green together, however your printer can simply make this colour using the Yellow toner.
Red: Monitors are capable of transmitting one simple Red light to create this colour however the printer will have to combine the Magenta toner + Yellow toner.
White: Transmitting the colours Red + Green + Blue to your monitor will produce White, however your printer will not use any of the Cyan, Magenta, Yellow or Black toner as generally you print on paper that is already white.
Black: Your printer can create Black by combining Cyan, Magenta and Yellow together or can solely use the K Toner (Black toner). The monitor turns off all RGB values to produce Black as the RGB colour models use the concept of adding colours (additive) to create other colours.
Check the settings on the printer driver to ensure you are selecting the correct settings for the application being printed.
The document and media type have an effect on the colour printed.
You can also adjust the brightness, contrast and colour balance under the Image Settings tab.
If these do not achieve the desired results you can download the ICM profiles that are included in the driver (CD or from the website) for inclusion into the graphics package you may be using.