Okay, imagine you have a pack of crayons, and you know that you can make different colors by mixing them together. Sometimes, you may even see something called a new color that looks like it doesn't exist in your pack of crayons!
Imaginary colors are sort of like that. They are colors that we can't see, but scientists and mathematicians can use special rules and equations to imagine them.
You know that when you mix red and blue crayons, you get purple. So, if you imagine that purple is a sound or a wavelength of light, you can also imagine a color that doesn't exist in your crayon pack, like a shade of purple that is so dark it almost looks black or one that is so light it almost looks white!
In the same way, scientists can imagine imaginary colors by using special rules that help them think about light in different ways than we can see it with our eyes. Although imaginary colors are not things that we can see, they can help us understand more about the way our eyes and brains perceive color!