First I assume you mean to the touch and in appearance. Pine snakes have keeled scales which aren't smooth like king and milk snakes and will give the overall appearance of a less lustrous wet look.
Black pines do however shine a brilliant black color especially on the belly scales.
But most pits are kinda rugged looking in comparison to kings and other smooth scaled snakes. My Black Pine looks what you would call dryer in appearance as compared to a King Snake but is a robust Lustrous Black on both Dorsal and ventral scales. Hope this helps and maybe someone else could give their opinion on this subject matter. I believe what you are referring to is your opinion between the differences in smooth and keeled scaleation appearance in snakes. Pine snakes have keeled scales which aren't smooth like king and milk snakes and will give the overall appearance of a less lustrous wet look.