Change color from white to yellow

Question

How do I change white color on the green background to yellow one in the following setting ?

Answer 1

When you use the tools without understanding what they do, you can't have any control over the result. If you are learning blender you you will get more satisfaction if learn what each element is doing, before you break the rules and use them for other purposes...

You are using vector curves to control RGB information. Usually you shouldn't plug information into a socket that requires other kind of input. A RGB curves node would be easier for your needs, as it will allow you to control Luminance (C) and the values for each color channel (RGB).

Read:

What is the meaning of the color of the node sockets in the node editor?

Yet, when you plug RGB into a vector curves node, the curves will act on only one channel of the image. The curve for $X$ will affect the Green channel, $Y$ will affect Red, and $Z$ will affect blue.

If you need yellow you need to sbutract blue or add Red and Green.