Professionally trained Graphic Designers spend weeks, if not months learning about this subject. For some of our print processes; white ink, letterpress, foiling and embossing it’s essential that your artwork is in the right format as the printing software will only recognise CMYK.
CMYK (Cyan, Magenta, Yellow, Black - K stands for Kohl, black in German, as B might be confused with blue) is used in printing and RGB (Red, Green, Blue) is for on-screen digital use, TV and video.
If your artwork was created in RGB there’ll be a big difference in the colour when it’s printed. RGB colours look really vibrant on-screen partially because the monitor is backlit which intensifies what you’re seeing. If you print a graphic at home, you’ll instantly see this difference. On the left is an approximation of the same file in CMYK, and on the right RGB
So, if you’re designing in Illustrator or InDesign, make sure your document profile is set to CMYK. This should be your default as a print designer:
Indesign: Edit/Transparency Blend Space/Document CMYK
Illustrator: File/Document Color Mode/CMYK Color (you need to have your file open on screen to check or change this in Illustrator). You can also see the profile information on the info tab of your open file.
If you're designing in Canva, then you'll be using HEX codes and your artwork will be in RGB. If you're using Canva Pro and save your artwork, you can choose to save your print ready PDF as CMYK.