There's a degree of staining with many developers containing Hydroquinone and the stain component of most modern staining developers is relaively small compared to early staining developers.

Even an unstained negative (or print) can be affected by prolonged exposure to bright light, particularly sunlight, a silver sheen forming in the emulsion surface, worse if the emulsion's been poorly fixed and/or poorly washed. It's always been recommended that negatives are stored in the dark.

There's plenty of stained negatives around that have been contact printed a great many times over the past decades and are still producing high quality prints today.

Ian