I have tried 3 different samples of a sphere in coloured pencil Faber Castell. I have used the same amount of pigment to the 3 spheres.
First one done only with pencils and burnished with the pencil burnisher (only wax no pigment to it). = a bit grainy. You could still add more pigment to it.
Second one done with pencils and burnished with solvent Taltine with a soft brush. = pretty good but it marked a bit.
Third one done with pencils and my hair drier And rubed with a bristle brush. = very good it is smooth and you can still apply more pigment as well as the others.