I'm hoping for 2 answers then. First for my own use can I add 14k
to 18k to tone down the color of 18k I'm using now. Second, can
anyone suggest an 18k color and where they bought it, that they
feel sells to customers that wear mostly 14k?
If you add the 14K to the 18K, it will no longer be either 14K or
18K, because those numbers describe the proportion of gold to
accompanying metals, only.
There are numerous different mixtures of gold with base metal that
give different colors and can be labeled 18K, assuming the gold
content remains 18/24, or 75%, so what you can do is find an
opportunity to look at as many different 18K samples, together, as
you can, and then pick the one you prefer.
If you decide that the color is more important than the gold content,
that's fine, but you must then label or describe it with respect to
its actual karat, whether it be 14K, 16K, or whatever you end up
I have seen color illustrations in catalogs that showed the
different colors in the range of a particular karat, but that depends
on printing quality, age of the ink, etc -- find some you can look at
in person, if you can.