How to make my mesh's color unaffected by lighting?

I have asked this question before with this description: “I have a cube that switches between black and white, but only if the room is lit with a white color will it be white. How can I make the cube white regardless of the lighting?” and was told to tie the texture with emissive and not just color.

However, there is still a problem. At high frequencies I get a reddish pinkish (i think intermediate) color, which I didn’t before I played around with lighting. How do I get rid of this and keep it purely black/white?

I think you can take out the material nodes for extra things like reflection, roughness, etc.