Converting CMYK to RGB preserving colors in Adobe Illustrator

[Livio_The_Lazy_Dog]

Hello All,

After a long chat with assistance I've been redirected here since they had no idea.

I'm trying to convert an .ai file from CMYK to RGB preserving the colors. I am after vectors files in RGB. I have been able to export PNGs in RGB that are prefectly matching with the colors in the CMYK one, confirming that I am working in the gamut, this conversion is possible but I can't see a way to make it heppen in Illustrator.

The only way I can see is to go File > Document Color Mode and change to CMYK to RGB. By doing this the colors change radically. I have seen that there are very small options for the conversion under Edit > Color Settings > Conversion Options; I did play a bit with these parameters but nothing that really matches the original colors.

It strikes me because it should be such a simple thing.

I have attached the files: the first one is how the CMYK document looks like and how the PNG comes out, the second one is how Illustrator changes colour mode from CMYK to RGB.

[Monika Gause]

Please embed the images in your post, so we can see them side by side.

Please tell us the exact color settings.

[Livio_The_Lazy_Dog]

The pictures are embedded, for some reason they don't show as previews but as attachments. For convenience I'll attach them into this reply as well. 

RGB: iceRGB v2

CMYK: ISO Coated 300 v2

[Livio_The_Lazy_Dog]

I just relised that I was attaching the files and not posting the pictures. 

RGB: eciRGB v2

CMYK: ISO Coated v2 300% (ECI)

How it looks in CMYK and properly exported in RGB.

How it crunches the colours when changing the colour mode to RGB

[Met1]

How/where are you making the png files - out of Photoshop? If so your color management is not set up universally, go to Bridge and choose the same profile you are using in Photoshop - assuming that is the one that is converting better for you.

If this still fails, just build your doc in Illy in rgb using the starting points from your png file(s).

[Ton Frederiks]

Can you show your Edit > Color Settings...  and the document color profile of your CMYK document?

For the document color profile see the option at the bottom of your window:

[Livio_The_Lazy_Dog]

It says "untegged CMYK".

Why is that? I thought I have already assigned the CMYK profile in colour management. 

[Ton Frederiks · Accepted solution]

Untagged CMYK is the problem. Go to Edit > Assign Profile... and assign the profile you think it should have.

Is there a reason you use Apple CMM for conversions in Adobe applications?

Why Absolute Colorimetric? Perceptual or Relative Colorimetric would probably give better results.

[Livio_The_Lazy_Dog]

Yes, this is it. I wasn't working with the right colour profile instead only diplaying it.

Is there a reason you use Apple CMM for conversions in Adobe applications?

Why Absolute Colorimetric? Perceptual or Relative Colorimetric would probably give better results.

No, you're right, this is just a leftover from a few tests I've done, I was trying to see if the problem was sitting with these parameters.

Thank you, this has been very helpful.

[Ton Frederiks]

Good to hear that helped.