It's been such a long time since I've posted a franken.
I mixed Color Club Get A Clue with a little bit of Sinful Black on Black (about seven parts GAC to one part black), two coats. It's mauve grey, neutral grey and purple grey at different angles. Not duochrome but still neat.
Sorry to be so vague on the recipe. This was a single manicure batch. What happened was I accidentally glopped 3 drops of black into my palette, and I just ended stirring in more and more of Get A Clue in until I was satisfied with the color. But the notes with my test mix indicate that this was 7 parts to 1.
Thoughts: Get A Clue is a light pink creme that leans a bit blue. Any standard light pink would work by adding a little blue creme or jelly. Sinful Black on Black is a very neutral (and highly pigmented!) black. Sometimes black polishes have a blue base. In which case I would have had to use a standard light pink. I really should do a swatch and comparison of Get A Clue to show what I mean. On it!
Anyway, I was trying to dupe Sally Hansen Concrete which is already hard to find and it was released less then a year ago. SH should really rethink their distribution method/business strategy! I've never seen it in person so I don't know how close I got, but I am satisfied with my franken. I patted myself on the back and ordered a bottle of Nubar. :D