Initially, under an 8 watt cool white fluorescent in the darkroom while the print is still wet. (This is a bit too bright, and I will switch to some white LEDs soon.) That tells me if my exposure is pretty much on. Later, when dry, under the multiple fluorescent shop lights that light the darkroom. That tells me if the print is worth keeping and if I need to reprint with some more subtle changes than I recognized before. Critically, under high CRI daylight fluorescents in my lightroom area. That tells me whether I can mount and exhibit the print. (Not many pass.) Fortunately, the exact color of the light is not too critical for black and white, and regular fluorescents and incandescents are quite OK for routine evaluations. But for critical evaluation, you should look at the print in in the same light as it will be in when exhibited. For black and white especially, the matting and framing can have a greater effect on the look of the print than then light. It is often helpful to keep some mattes around of the kinds of material you like to use and to look at the print under them for a critical evaluation.