why the resulting color is darker than the base color? (adobe illustrator-darken blend mode)

Question

i'm learning the adobe illustrator blend modes. For the darken mode, according to adobe help page, it is described

Darken- Selects the base or blend color—whichever is darker—as the resulting color. Areas lighter than the blend color are replaced. Areas darker than the blend color do not change.

and this is my test

The circle in the center is on top of everything, put on darken mode, opacity 100%. Blending with the circles above, and to the right results in either base or blend color, whichever is darker. That's right. But, why blending with the blue circle to the left creates a blue-darker than the original. I think it should be the base blue according to help page text( because the base blue is darker in value than the tan color on top)

Answer 1

It's because your document is in CMYK color mode.

Note, if you switch the document color mode to RGB, the results will be as expected.

Blending modes in CMYK are not as predictable as they are in RGB. Darken often equates to "multiply" if there's a similar or conflicting value between the objects. This appears to be the case with the blue. You have two object of relatively the same value, but different hues sitting on top of one another... it confuses Illustrator's CMYK rendering so it creates an appearance similar to the Multiply blending mode.

I won't begin to try and explain why this happens in CMYK color mode. Truth is I can't explain it. I just know Illustrator has treated CMYK blending this way since it was first introduced in Illustrator 10 and Adobe's done very little, if anything to address it.

You'll also find blending modes such as Screen, Color Dodge, Color Burn, etc all result in unpredictable appearances in CMYk color mode.

When I work in CMYK, I only use the Multiply blending mode (if I use any at all). It's the only consistently predictable blending option other than transparency itself (Because in CMYK color mode Multiply is essentially the same as setting an object to overprint).

For your specific artwork, I'd merely use object stacking without blending to achieve the colors. I realize this is a rudimentary example, but often you don't need blending modes for anything created in Illustrator. They are merely shortcuts.