CMYK VS RGB - what is it?

As most of you might know, CMYK (Cyan, Magenta, Yellow, Black) and RGB (Red, Green, Blue) are the colour spaces used to generate a wide array of different colours that are used in a variety of settings.

The difference between RGB and CMYK

 

○ RGB colour space is used to display images and colours on screens

○ CMYK is used for printing, and for rendering colours in a physical environment

Consequently, it is absolutely crucial that you set your artwork file to CMYK mode when preparing to send it (to Zenprint) for printing. Artwork files using the CMYK colour space are a prerequisite when it comes to 4-color printing, since files set up in the RGB space will cause severe colour deviations when printed.

1. Digital Pictures & RGB - What is RGB and when is it used?

RGB stands for the three physical primary colors Red, Green, and Blue. By mixing these three colors in varying ratios, one can achieve a total of about 16.8 million color shades. Given that they are the physical primary colors, every image in the digital domain inherently uses them as a basis.

By digital domain, we mean anything that is displayed on a digital screen e.g. this blog on your screen right now or photos taken with a digital camera or phone. The defining characteristic of the RGB colour space is that colours are perceived by mixing different colours of light.

RGB are lighting colors. As a result, RGB is an additive color model:

The more color is used → the lighter the final image will be. When all three primary colors are set to 100% the perceived color will be "white"

 

2. CMYK & Printing -  What is CMYK and when is it used?

CMYK represents a subtractive model, in which the three colors Cyan, Magenta and Yellow. The Key color Black, are successively printed against a white background.

The more colour is used, the darker the final image will be. When Cyan, Magenta, and Yellow are all set to, the achieved colour will be a very dark brown. This is why the Key colour is required to create a true black rather than a dark shade of brown.

In CMYK, colours are applied to the paper one after the other in the proportion that will result in the required colour. This means that, in theory, about 4 billion colours can be created within the CMYK colour space (however with today’s technology only a small portion of those can be displayed on a monitor or printed).

CMYK Color

3. Setting the right color space for your print files - What to be aware of and how to make sure my artwork settings are optimised?

If the wrong model is used it can cause big problems when preparing print files! Photos, images and logos are widely available in RGB format on the internet, but printing them as such causes discrepancies in colour. To avoid unpleasant surprises, any files with RGB colours need to be converted to CMYK colours prior to printing. However, a one-to-one transfer of colour from one space to the other is not always assured, so slight deviations might occur. This is why it is best to set your settings to CMYK when starting with your artwork.

Here are a set of instructions to adjust your settings and for further information this tutorial should answer all your remaining questions.

Tip!

Make a habit of converting all pictures to CMYK when exporting them for printing (this can be done using basic photo editing software).

This example lets you see the difference on-screen (Note that the difference when printed should be more apparent). As you see, the colours become much more vivid and clear once converted to CMYK, hence ensuring a clean final print outcome.

RGB:

CMYK:

CMYK Color

At this point you should understand a little bit more about the difference between RGB and CMYK.

Concluding Rule of Thumb:

1. Digital (on-device) format should always be RGB (which is not printed, but shown on-screen)

2. Anything which will be printed should be in CMYK format

You should now appreciate the importance of setting your files to CMYK mode; and can now make sure that your artwork files have been set properly before sending into production. Converting your artwork to CMYK format will ensure that your artwork can be printed in the best possible quality, so we can add you to our list of satisfied customers!