I created a color scheme from the picture, but I need another color, how to choose?

Question

Design

Created on the site color.adobe.com, but I need another color that is not present in the picture, the customer wants it, the color is black (this does not mean specifically #000000), but some shade of it, as you do in similar cases?
How to choose another harmonious color to an existing range?
Maybe there is a program or an online service of some kind?

Answer 1

Your eye is the best service (if you have a good monitor, of course). And all these programs for the selection of colors can still give that slag, although they work according to well-known principles. So it is foolish to rely on programs in this sense. Besides, it all depends on the task. For a poster, for example, a color scheme may be acceptable that would be highly undesirable for an interface. And I usually take black to blue, as it seems to me the most natural.