What’s the difference between CMYK and RGB?
Why do print files need to be CMYK?
The RGB colour spectrum is much larger than the CMYK spectrum. This means that some colours, like fluorescent orange and green, aren’t available within the CMYK spectrum. Commercial printing presses print onto white paper, so to get the best end product it’s a really good idea to convert your designs to CMYK before you send it to us. Even if you send an artwork file in that’s not set up in CMYK, we’ll automatically change it for your when we send your proof.
Setting up black for digital print
If we’re printing your project through our digital press, and you’d like to include a black background you will need to set this up as a mixture of CMYK to get the best result/rich black coverage. For example, C-40, M-40, Y-40, K-100. If the black is set up as a percentage of black only you’ll be left with a mottled grey result.
What are spot colours?
Spot colours (sometimes called solid colours) are pre-mixed inks that are used when creating printed products through litho process. As the inks are pre-mixed this means you can achieve colour results which aren’t possible through CMYK digital process e.g. metallic or bright shades, you can also achieve consistency across a number of printed products.
Unlike CMYK, spot colours can be specified using a universal reference system e.g. Pantone but you must set the colour to a spot reference in the PDF file otherwise it will be a make up of CMYK.
If you supply a file which is set to RGB we’ll need to convert it to CMYK for printing, this does mean the colour will change slightly therefore, the printed result won’t be the same as shown on screen.
When to use CMYK, RGB and Spot Colours:
- RGB should be used for on screen digital artwork.
- CMYK is suitable for printed artwork when colour accuracy and consistency is not essential.
- CMYK is suitable for low quantities of printed artwork on a small budget (digital print)
- Spot colours are suitable for printed artwork when colour accuracy, coverage and consistency are important.
- Spot colours are suitable for printed artwork when unusually bright or vibrant colours are required.
- Don’t assume the colours you see on your screen will appear the same as they do on another screen.
- Don’t assume printed items will be the same colour as the artwork you viewed on your screen or created on your own printer.
- Request proofs if you’re concerned about colour.