How to make champagne gold!

Hi everyone , I am starting to make a champagne gold ( the color) but I dont know how is the component of it ? Please , help me about the formular ! Thanks a lot !
I know the 18K rose gold including 25% copper and 75% gold …
and 18k (14K) champagne gold including ??

Anyone can help me !?

Sorry friend i do not know. If nobody here answers, you can go to reddit and ask in various subreddits (jewelrymaking/metallurgy/etc.)

Google can at times be helpful.
One search gave me this among other links:

When you first posted your question, I did a quick search and all I could find was that it is an alloy of white gold. Why don’t you call a refiner and ask. Try Hoover and Strong or Stuller. There are many others. They may not tell you the alloy, but they may be able to help you find a source. Personally, I try very hard not to work in white gold. Good luck…Rob

Not going to be helpful in as how much but,
Copper is added to make many gold-colored alloys, but additional copper creates pink and rose tones – the more copper, the deeper the effect.

Suggest that you keep adding till you get the colour you desired. God bless