Having an issue with multiply blending mode

[dDembicki]

First off, I want to make sure that what I want to do is even possible. Can you use the mulitply blend mode with spot pms colors? 

I have a doc that has two instances of the same art that is multiplied, one on top of the other, to make the color deeper. The art is made up of multiple shapes that all have the same radial gradation of one spot color, say 30% to 100%, but with different radii. Below them is a rectangle that is also filled with the same spot color (no gradations). 

If I change the rectangle below the two multiplied instances to spot color, I lose the multiply-ness. (image 2)

If all the colors are CMYK, it all multiplies as expected. (image1)

I'm trying to replicate this artwork and be able to change its colors for different flavors. Is there some kind of best practice for achieving this? 

Please advise, thank you all.

[Ton Frederiks · Accepted solution]

You may be able to multiply various tints of an spot color, but you cannot make a single ink darker than it is at 100%.

[dDembicki]

Haha, good point. It's been a long day. Thanks.

[Ton Frederiks]

Glad I could help.

[Ton Frederiks]

You may try it in RGB color mode to get the effect you are after.