The OP has not said whether hes using Contact Paper or Enlarging Paper and also has not said if hes using an enlarger for exposures.
Have a look at Kodak's Tech. Bulletin G-10 (for AZO paper):
http://www.kodak.com/global/en/professional/support/techPubs/g10/g10.pdf
In particular this paragraph:
"Contact printers generally have a very high level of illumination. In order to keep exposure times within reason, contact printing papers, such as AZO Paper, are made with a relatively low speed. Therefore, its not practical to use contact papers with an enlarger as a light source." [Presumably because enlarger light sources are not considered bright enough for contact papers].
Contact papers are silver chloride graded emulsions and are very slow papers. Graded enlarging papers are silver chloro-bromide emulsions with much faster speeds. Graded papers respond to blue illumination, variable contrast papers to blue (for high contrast) and green (for low contrast).
Most of us use a simple incandescent bulb for contact papers and rig it so its distance from the paper can be varied to keep the exposures reasonable.
Ive not tried LEDs with contact papers or graded papers, but Id expect LEDs with lumen output comparable to incandescent should work as long as the spectral distribution contains sufficient blue.