Settings to keep CMYK image 100% unchanged through illustrator

[rlaine]

I think I've done this a thousand times, but now can't seem to succeed.

I have Photoshop created image that has C and K values, but empty M Y channels. I have saved the image without any profile (don't color manage this document).

Then I import image to illustrator that has no color management either and export the AI document to PDF with "no color conversion" and still end up with image that has 1% values in M and Y channels. 

What am I doing wrong?

[Monika Gause]

So your color settings in Illustrator are "Emulate Illustrator 6"?

Or did you set the CMYK conversion to "Preserve numbers"?

[rlaine]

No "Emulate Illustrator 6".I have tried many combinations, saving image from Photoshop with profile (fogra39) and Preserve Embedded Profiles in Illustrator and saving without profile (don't color manage this document) and Preserve Numbers in Illustrator, but I always get unwanted 1% data in otherwise empty channels.

I now got the same result from Indesign too, so clearly i'm now doing something wrong.

All illustrator graphics come with correct values.

[Monika Gause]

Please tell us the exact settings and upload a sample document so one may try and reproduce this.

[rlaine]

I actually did some testing and a fresh AI document with exact same image and settings worked while the old file produces M/Y channels with 1% ink at darkest (?) areas. Mystery. The original AI may be opened PDF originally and worked from there, but 90% of it is new artwork, including the image.

I don't think I can upload the files publicly as it contains licensed photo.