Hello: Is there some idiomatic translaton for this phrase?
Complete sentence is: Usando la lampara violeta o negra sale negro, no brillo como el fluorescente. It has to do with stamps and their appearance under ultraviolet light. Thanks, Me
In my opnion, negra sale negro, has to do with a kind of lamp, more precisely a kind of light which was called black light. It was very popular in the 70's and was commonly used when encoding a message written with a special marker which was "invisible" except when exposed to that light.