We demonstrate---experimentally and theoretically---that resonances obtained
in electromagnetically induced transparency (EIT) can be both bright and dark.
The experiments are done using magnetic sublevels of a hyperfine transition in
the D1 line of 87Rb. The degeneracy of the sublevels is removed by
having a magnetic field of value 27 G. The atoms are contained in a
room-temperature vapor cell with anti-relaxation coating on the walls.
Theoretical analysis based on a two-region model reproduces the experimental
spectrum quite well. This ability to have both bright and dark resonances
promises applications in sub- and super-luminal propagation of light, and
sensitive magnetometry.Comment: 16 pages, 9 figure