The ionic silver solutions produced by generators used by home hobbyists tends to be photosensitive and will deteriorate over a short period of time if not shielded from visible light. By storing such solutions in amber bottles the deterioration is reduced. The most photosensitive solutions are produced using the low voltage DC process, often by using several 9 volt batteries.  The requirement for an amber bottle indicates a photosensitive, unstable solution. Only the lowest quality solutions are photosensitive.
High-quality products are not photosensitive and do not require an amber bottle.