Color doesn't match between CMYK/RGB mode document

[Trellat]

Hi folks, first time for a while here!

I've just realized something that annois me, and it probably happens for years and years :S

I created a CMYK document and work with several colors on it, this are the blue color results:

But when I switch that document to RGB mode, just to export the assets, the color changes:

Am I doing something wrong? What I should do to work always with same colors? Should I work with two different files, each one with a different color mode, to manage the wanted color in each moment?

Thanks in advance!

[Monika Gause · Accepted solution]

You need to work with 2 different files, yes. Or just export to RGB color mode and live with whatever result color management will give oyou.

An Illustrator document can only have one color mode.

[Trellat]

Hi Monika,

thanks for your answer. I didn't know about this behavior... :S

[Ton Frederiks]

Some colors cannot be reproduced, an ink like cyan cannot be correctly reproduced in sRGB, but may have a match in Adobe RGB.

[Trellat]

Hi Ton, thanks for your response.

I knew how colors work, what I thought was that Illustrator maintained the color values despite changing color mode of the document.

[Ton Frederiks]

It is almost impossible to keep color values the same when converting between color modes.

Even when a color can be reproduced in RGB as well as CMYK. When converting  from CMYK, the color wil first be converted from 4 color components to a 3 color component device independent CIE color space and then to 3 color RGB components.

[Bobby Henderson]

To add to Ton's response, the RGB color mode has a much wider gamut range than CMYK. Many colors in the RGB color space cannot be reproduced in CMYK. The two color models are based on two physically different systems. RGB adds different colors of light together (additive synthesis). Adding red, green and blue light together in full intensity creates white. Our computer monitors, TV screens and smart phones operate on that model. CMYK builds colors by taking away wavelengths of reflected light on printed surfaces (subtractive synthesis). As more inks are added the colors get darker; you'll get a "rich black" by adding percentages of all four CMYK colors together. The dynamic range of printed material is far less than color built by directly emitted light.