Porcelain veneers: too white and I would like them to make a bit darker.

Unfortunately, the only way to change color to porcelain veneers is usually to replace them.  This means cut them off and make a new set.  Some cements will darken a LITTLE bit over time, but not soon and not much.

its my request to upload pics, so i can guide u better. if u have full mouth veneer, thn no need to worry. u will become use to that. sometimes its psychological effect. because u compare old yellow teeth with new bright white veneers. and just because of that u feel its too white. but others will appreciate yr white smile. so enjoy it. 
if u have 6 or less veneers thn  re-veneering is must. 

Hi,
It is always easier to see a photo to evaluate the shade. If the veneers are slightly whiter, then drinking a lot of coffee may darken them over time. If they too white, then you have to redo them. That's the beauty of veneers, they actually don't stain. If they become darker with excessive coffee drinking, they can actually be polished back to their original white. I am sorry to hear about your disappointment, veneers are such a great tool to improve one's smile.
Best,
Dr. Joseph Goodman