Here is a typical 1890s advertisement for the Julius Hebbel Studio on Gay Street in Baltimore. Ads like these appeared in the SUN jumbled together with ads for clothing, canned goods, plays, patent medicines, etc.
Before electric lighting, photography studios had to have large windows and skylights. Producing good results in a variety of lighting situations required some skill.
A good studio practitioner chose backgrounds and props that suited the client. Children were notoriously difficult to photograph without fuss. Studios that advertised “instantaneous portraits” were aiming for anxious mothers.