Adobe Illustrator CS 6 17.0.0 Pipette gives "wrong" color?

Question

A friend gave me a logo which he created in Adobe Illustrator CS 5 with a rectangle in blue color (Cyan 100%, M 0%, Y 0%, B 0%) and saved it as PDF. I opened the PDF-file in Adobe Illustrator CS 6 17.0.0. When I used the pipette to get the color information the result was: Cyan 74%, Magenta 24%, Y 0%, B 0%.

I tried to put two other rectangles over it. One with the original color: Cyan 100%, M 0%, Y 0%, B 0%

And one with the measured color: Cyan 74%, Magenta 24%, Y 0%, B 0%

The one with the original color looks 100% same like the logo. (different values...) And the one with the measured color looks different. (same values...)

Any idea? Is it a bug?

Answer 1

Adobes pipette reads only the RGB values and calculates the CMYK values even if the document is in CMYK - Mode. If you make a small calculation than you can see that CMYK can hold about 10^8 numbers (100 C; * 100 M; * 100 Y; * 100 K;) while RGB can only hold 16,7 * 10^6 (R 256; * G 256; * B 256) which gives a gab of 83*10^6 values. So there is more than one value in CMYK that gives the same RGB value as another CMYK value.