Colour mixing

Subtractive

This means that the colours must be subtracted to obtain the white, i.e. nothing should be printed. The white is simply the non-existence of the colour.

This principle is exactly the opposite of RGB. To obtain the white colour, it is necessary to add the colours red, green and blue to obtain the white light, that is, if it is an additive colour mixture.

How do you get the colour black?

You could come up with this reasoning: If in the RGB model the white is obtained by combining colours and the black is obtained by shooting and if in the CMYK the opposite is the case (white is obtained by removing the colours), then the black colour is the mixture of all colours. This is the difference between these two colour models.

However, if you have already tried to mix all the colours, you will have noticed that the result is not a perfect black. It is therefore necessary to add a fourth element: Key (black). For this reason, the CMYK model has 4 initials and the RGB only 3.

The result on a printed sheet is never exactly the same as in real life, as not all colours are present, but a crossover of colours.

However, you can get so close to the actual colours that it is (almost) indistinguishable to the human eye.

Did you know?

You may have wondered why the black colour of the CMYK model is represented by a K (Key). Wouldn't it be more logical to be B (Black)? It used to be. However, since the letter B for blue already existed, especially for the RGB model, the letter was changed to K to avoid confusion.

The 5th colour

When printing, there is a fifth colour to consider: the colour of the paper.

If the paper is yellow, e.g. newsprint, the colours must be set to a lighter profile and vice versa.

The paper colour, surface texture, paper thickness and opacity (light transmission) are important.

Sequence

The order of the colours can result in the colours looking different to our eyes.

For example, if you put red first and then yellow, the result will be different than if it were the other way round. This is because the colour at the top is the most dominant.

Lighting

The lighting also has an effect on the colours. It is therefore always a good idea to use lamps with standard light when analysing the colours.

Conclusion

Printolino takes colour conversion very seriously. Before printing your images, the colours are controlled in detail. Colour analysis tests are carried out regularly as secondary factors such as paper colour, ink manufacturer and even the printers themselves can vary to the point where you may notice a difference. With us, you can be sure that the colour conversion is very accurate and that the desired result is a realistic colour print.

We hope that we have been able to help you with this article about the colour models. For a more detailed explanation, watch the following video.

VIDEO - EXPLANATION OF RGB AND CMYK

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Colour models (RGB & CMYK)

What are colours? How are they created?