From what I can remember working in a goldwell salon, Elumen works on every single base. If you bought a package you should have some promotional material/education manuals and I'm pretty sure there's some paper that's shaded in different amounts to represent levels 1-10, you can paint some Elumen over it to see how it would show on every level. Obviously the most intense noticeable results will be on level 9/10 but it can go on all levels. Could be good for doing 'oil slick' type things? And don't quote me, and blame me if it does run but I THINK that Elumen doesn't run. They've got a 'lock' that you can apply that stops it running at all in future shampoo's & onto sheets etc