You might have experienced it, you want to order a flyer and you've already found a printing business. You've sent the file to them, but now they're calling you back: there's a problem with your file.
The printing company tells you your file is in RGB colours, and that these colours will end up being printed in a darker colour than they are supposed to be. They tell you to send the file in CMYK colours, but what does all that mean? What's the difference? No worries, we'll gladly explain!
What are CMYK, PMS and RGB colours?
What are CMYK colours?
CMYK stands for the colours cyan, magenta and yellow. By mixing these three colours, no darker colour than dark brown can be made, so the colour black (key) is added. CMYK colour has a base consisting of all colours in the colour spectrum. The colours are laid down and take away the reflecting light.
In addition, there's PMS (Pantone) colours
More than 1100 colours have been defined by a company called Pantone. These colours all have their own number. With these numbers, matching colours across the globe are guaranteed. This makes Pantone colours very suited for company logos and house styles. Pantone colours are not easily reproduced using CMYK. Pantone colours are acquired using 15 base pigments, including black and white. By mixing certain amounts of one pigment with certain amounts of another pigment, one colour from the Pantone colours is created.
Then what are RGB colours exactly?
RBG stands for red, green and blue. With this combination of colours, you can create very bright colours, as the starting point is light. A TV screen for instance, has a black screen when switched off (colourless). Light is added to this screen to create colours.
Why are RGB colours not accepted for printing?
A CMYK printer makes use of light-absorbing cyan, magenta and yellow ink, which are mixed using dithering, grids or another optical technique. CMYK printers place the colours on top of the print, which means the reflecting light is lost. This means the colours on the print come out darker on the print, compared to the computer monitor screen, as visible on the image below. This is why printer companies usually don't accept RGB colours and want you to send your files in CMYK. This lessens the chance of you being disappointed by the colour differences between what you want and what you got in the end.
Above, you can see a visual representation of the colour differences between RGB, CMYK and the printing result.
I set up my print properly, but there are still colour differences. How can this be?
It could happen that you find minor differences in the colour of the print you received. A possible cause could be comparing paper types with each other. The characteristics of different paper types can make your colours differ slightly too. Even when using your own printer, colours can come out slightly differently. The different production method could be the cause of these colour differences. Another possibility for colour differences are the colour settings of your screen or monitor. A flyer can look different across various displays, depending on the settings for example..
Tips to prevent colour differences
- Always compose your print in CMYK (or PMS for professional users)
- Make sure you have the colour codes of your most important colours
- Is having one single colour of great importance? Order PMS prints
- Minimalize the use of blue/purple colours in your print