Template for all pages except Admin-Interface?

hey there.. i have a little problem with my embedding:

everything looks nice for the frontend-side. But since i changed the templates to fit the design of my page (removed sidebar, added header footer, etc..) the space where the gallery is displayed is limited. (i modified the matrix theme)

so when i log in to the admin-panel i want the standard matrix template back..
but i dont know how to do that ?

so basically i want my template changes for all pages, but the admin-pages. is that possible somehow ?

thx in advance..