We’ve printed thousands of projects for hundreds of clients during our time in the printing industry and one of the most frequent mistakes we see is not recognizing the difference between RGB and CMYK.

In essence RGB is an additive colour model used to mix light (like the light found in your computer screen), whereas CMYK is a subtractive colour model used to mix pigments or inks (like the ink found in our printer). RGB and CMYK are essentially opposites!!

We find it’s common for clients to create their designs (intended for print) within an application such as Photoshop or Canva, which defaults to using the RGB colour mode. Because the media or documents created within Photoshop & Canva are typically published online (e.g social media posts) CMYK isn’t used (at least not as default).

The issue here is that when RGB designs are printed utilizing a CMYK printing process, the colours appear differently (if not properly converted) because they are opposites. Although a design might look absolutely perfect when viewed on a client’s computer, there will could be a distinct differences in colour between the printed version and the on-screen version.

What is RGB?

RGB is an acronym for Red, Green and Blue, and is the colour mode used for anything displayed on a screen whether it be a screen for a computer, laptop, TV, phone or tablet they all display in RGB. Examples of digital marketing that are created using RGB colour mode include social media posts, EDMs, digital billboards, and TV adverts.

Science on how RGB Colours work?

Screens display imagery with hundreds of pixels. Within each of those pixels is a red light, a green light, and a blue light and they light up in different intensities, creating over sixteen million possible colours in each pixel.

This is known as additive mixing: all colours begin and complete absence of light which creates a black colour, darkness and then red, green and blue light is added on top of each other to brighten it and create the perfect pigment. When red, green and blue light is mixed together at equal intensity, they create pure white.

What is CMYK?

CMYK is an acronym for Cyan, Magenta, Yellow and Key (here, Key means Black) is the colour mode most commonly used for print communication. Examples of print communication that would use CYMK colour mode include business cards, posters, flyers, stickers, banners and signage

Science on how CMYK Colours work?

If you look with a magnifying glass at a printed image, you will notice how it’s made of tiny dots of ink that are either cyan, magenta, yellow, or black.

The bigger the dot of a certain colour, the more that colour is represented. And because the colours are semi-transparent, when combined in various proportions, they create the full spectrum of the colour wheel.

As opposed to RGB, CMYK uses a subtractive model. All colours start as blank white, and each layer of ink reduces the initial brightness and absorbs light in a way to create the preferred pigment.

For example, if you completely overlap a magenta and yellow dot, or more precisely, subtract yellow from magenta, you end up with a bright red colour. If you subtract yellow from cyan, you would end up with green.

But what happens if you combine cyan, magenta, and yellow together? You end up with a dark brown colour. That is the reason the fourth colour key (aka black) was added to this model; in order to remove light completely from the image and display the colour in its purest possible form.

Can I convert my RBG colours to CMYK? How do I get Precise Colour Matching?

Yes! RGB colours can be converted to CMYK mode, we recommend talking to your Graphic Designer about this process. If you currently do not have a Graphic Designer please chat to our friendly team about how to start this process.

For precise colour matching, please also contact us. We can provide you with printed samples on your stock of choice for you to colour check. Choice of stock is important as this can also affect colour, see the following link for more details (article link here). Once this colour proof is approved we will strive to match the colour of the proof when printing your final piece.

Feel free to request a printed colour sample if you are concerned about how your colours will print.

How well will my print match what I see on my monitor?

Generally your print job will be close to what you see on screen however due to large differences in monitor calibration and the different technologies used, some printed colours may not exactly match the colours viewed on your screen/monitor.

It also important to note some RGB colours cannot be reproduced as CMYK colours, however if you are after a very specific colour to be printed and it’s not available in CMYK, in this case we can offer a third colour option; Pantone Colours.

Feel free to request a printed colour sample if you are concerned about how your colours will print.

Will the colours match a sample I print out on my computer?
Any item we produce for you is very unlikely to match your home/office inkjet printer, as our equipment is calibrated to very strict industry standards for ink density and colour. As there are variations in conditions and equipment, we do not recommend using home or office printers to predict the quality of images or colours printed at our facility.

Feel free to request a printed colour sample if you are concerned about how your colours will print.

Can I print my artwork created with RGB colours?

The short answer to this is yes and many printers will accept artwork files in RGB without questioning you. HOWEVER this is generally not something we recommend, when printing files that were created with RGB mode, we cannot grantee colour consistency or expected colour values.

If you answer yes to the any of the below we recommend having your artwork creating in CMYK mode.

• Do I have a brand/business that requires colour consistency?
• Am I a brand/business that will be printing across different mediums?
• I require consistent and accurate colour values