CMYK to RGB - Simple issue

[yash-lucid]

Color science breaks my brain, please help with a VERY simple issue.

Client has given me a CMYK document for a printable billboard, which needs to turn into RGB for After Effects.

When I go to File > Document Color Mode > RGB, the colours change.

I need the colours to be preserved as close as possible but in RGB, instead of a big shift.

Edit: Sometimes Doc Color Mode to RGB menu works with colors unchanged, sometimes it doesn't, I'd like to know why please

[Dave Creamer of IDEAS]

What are your color profiles being used? It's odd since most of the CMYK color range exists in even the smallest RGB profile. What happens if you rasterize the file in Photoshop and convert there?

[yash-lucid]

I don't know how to check color profiles... I tried.

The colours only show correctly if I open the PDF in Adobe Acrobat, once open in Illustrator, colours are off whether set to CMYK or RGB. When open in InDesign, colours are also CMYK and different to PDF which shows correctly on screen, if I change doument intent from Print to Web, it still doesn't reflect the correct colours as Acrobat does.

If open in Photoshop, colours are still CYMK, even if Image > Mode > (set to) RGB. Regardless I can't use Overlord to transfer my vectors over if photoshop.

[Dave Creamer of IDEAS]

In Illustrator, what happens if you turn off the GPU Performance preference?

If the image is rasterized in Photoshop and you convert the image to RGB, the colors would not be CMYK anymore. You could also export as PNG from Illustrator if you wish. PNG only supports RGB and grayscale. I'm assuming the graphics would need to be rasterized in After Effects anyway, unless you are using them as masks. 

Not sure what Overlord is...

[yash-lucid]

Turning off GPU performance made no change.

It doesn't make sense to rasterize in PS since the incorrect colours show, and it only shows correctly via Acrobat.

Same applies to a PNG export from Illustrator.

Here is a screen share of the correct colours as seen from the PDF in Acrobat on the left.
Then on the right is me opening that PDF up, and alternating between RGB and CMYK but having no luck getting the correct colours, specifically the yellow.

https://drive.google.com/file/d/16q4Wfq3F2OLfg29gZxLRGWRJkvjHsdUT/view?usp=sharing

Overlord plugin allows a button press to transfer vectors from AI to AE.

[Dave Creamer of IDEAS]

Any chance you could upload the AI file? 

(I noticed you opened the PDF in Illustrator rather than the AI file. Did the PDF have the AI file imbedded?)

PS: Overlord looks cool...

[yash-lucid]

There's no AI file, the original file is an InDesign file.

[Ton Frederiks]

Can you also share the PDF?

[Dave Creamer of IDEAS]

I didn't have the linked images so the color may be off on them. Is the color any better?

It's a PDF but open though Illustrator.

[yash-lucid]

Yep those colours are correct in Illustrator, how can I achieve the same result?

[Dave Creamer of IDEAS · Accepted solution]

Changed the 100K black to a rich black (40 CMY, 100K)

Changed the transparency space in InDesign to RGB.

Exported as PDF with colors unchanged. 

Opened in Illustrator.

[yash-lucid]

Amazing, thank you! 

[Bill Silbert]

The difference between CMYK and RGB color is actually quite simple. CMYK which is used for print jobs is basically a mix of 4 colors which are used as ink on a press: Cyan (a shade of Blue), Magenta (a purplish red), Yellow and Black (designated as "K" to avoid confusion with blue). By overlaying these colors in different percentages the appearance of full color can be achieved.  RGB color is a color based on light represented by the pixels used on a computer screen. This color space provides a much wider range of colors many of which cannot be accurately represented in CMYK. RGB colors that are not achievable with CMYK are referred to as "out of gamut". The problem that you're having with certain converted colors looking better than others when switching between the two modes is really a matter of luck of the draw in terms of the actual colors being used. Certain CMYK colors that are within gamut may appear closer to their original look than others when converted to RGB. Others will look wildly different. Usually questions like this will bring up instances of original RGB jobs looking dull when converted to CMYK. Your experience shows that the issue exists in either direction of color conversion.

[yash-lucid]

Ok thanks that's good to know about gamut being a sort of color limit which can cause inconstencies 

[Bobby Henderson]

Normally CMYK-based artwork translates into RGB fairly easily since RGB has a significantly wider color gamut range. HOWEVER, if the artwork contains any unusual fills or effects the colors can shift dramatically. Transparency blending modes in artwork are a major stumbling block. If objects have varying levels of transparency and the blending mode is something other than normal (such as screen, multiply, overlay, etc) the colors will shift seriously when transferred from one color model like CMYK to another color model like RGB.

It's likely the original CMYK artwork will need to be pasted into a RGB-based Illustrator document. The fills would have to be adjusted as best as possible before placing it into After Effects. The process may be do-able. It's not as bad as trying to take RGB-based Illustrator artwork with lots of transparency effects and moving it into a CMYK document.

[yash-lucid]

Thanks - I've linked a screenshare in another comment - Can you recommend a workflow to achieve the correct colours?