Weird color behaviour new to blender, so pardon me if this is a silly question.
I have two geometries and want them to have the same color , yellow. The color of the object needs to be diffusive , means that I do want the color to be there regardless the lights I have in the scene.
The two geometries have the same material, but they are behaving differently , the
face one is correct, the moon is not.
What I can see is that the face has a yellow color regardless the light while the moon is grayish and turns out yellow only when the light bounces the surface.
Moon has 1 material only
Face has 1 material only
I have removed the garbage and you can see just 1 material per object


It's not a camera issue as I not using this models within blender but exported as gtlf and while the face behaves well in both blender and gtlf , moon is yellow only when there is light on both blender and gtlf, so issue is not with the camera or the lights, issue is within the model itself.

Below the two materials
Probably the best way to approach it is to use a flat shader (color shader) without diffuse, the other way is to use the objects' normals in order to create a &quot;fake&quot; light and keep them always consistent regardless the light conditions in your scene (as it is done in most NPR approaches).
this is how a flat shader would look like (just an emission shader in Blender's context)
Emission Shader (flat)

and that's how an NRP would look like
Dot Product (Geometry Position)

or like this
Dot Product (Geometry Normals)

check the material setup here:

the second vector in the Dot Product node (math vector) will be  the source of your fake light.

Keep in mind that Dot Product gives also negative values, so you may need to clamp it for certain occasions