The colored version in the bottom has got a brighter color to compensate the darkening:

In the next version the blending mode is still = Luminosity, but the bright spot is substantially darker. Or you can if the used blending mode is = Multiply. If you want the brightest area as colored you cannot have full white in the gradient. The white area can present a gloss which is too bright to be shown as colored in the RGB system. You can as well have the colored version on top and let it have blending mode = Color. Let the grey version have blending mode = Luminosity. Place (align or have point snaps ON) the grey version above the colored version.

Make also a duplicate of the circle and fill it with solid color: The older revisions are readable and the comments are valid for before 2021 versions.ĭraw a plausible greyshade sphere by applying a radial gradient to a circle. In addition Inkscape 1.0 works a little better than older versions. This answer is rewritten because it contained much clutter which was gradually fixed due the given comments.

Inkscape 2d to 3d