Keeping true color of 3d objects in Unity

For 2d game I need 3d objects with default colors. For example, this cube, all of whose faces are painted in different colors, but it looks dark without a light, and with a light brightness of the faces is changing. How can I keep the true color of the cube?75814-stack.png

You will want to disable directional lighting, and enable “ambient” lighting. This will allow all faces to be lit equally. But beware, this can turn what looks like a 3d cube shape, into what looks like a flat blue diamond shape, on screen.
Here is the docs on how to get that setup.