Dark fire
From Ardrana
The dark fire spell provides a small, lightless campfire when cast on a bronze brazier. This fire puts out heat and burns, but emits no light in the normal visible spectrum, nor does it create smoke. Objects set ablaze by the dark fire burn normally, emitting both smoke and light.
Note: This spell originally appeared in this form in Polyhedron Magazine by TSR. Its inclusion here is for the purposes of providing context for the campaign only.