Dating old family photographs
Your ancestor may have only owned one nice dress or suit that was used for all sorts of occasions.
Perhaps they did not own a nice suit of clothing and borrowed one from the photographer.
A woman I knew who was also involved in the same scrapbook company told me about a collection of old photos she had inherited from her parents who had long since passed away.
My friend explained to me that no matter how hard she tried, she could not figure out who the people were in these photographs.
This site includes an easy to understand history of 19th century photographic techniques, along with photographic examples.
Photo Tree has an archive of 1,000 photos that you can use to compare your photo and help yourself figure out the date a photograph was taken.
We've all heard terms like Cartes de Visite, Cabinet Cards, and Daguerreotypes.
One reason is that people did not purchase clothing as often as we do now.
I find it helpful to use a web site as a reference point.
Photo Tree, is a website dedicated to 19th century photography.
Likewise, The Costumer's Manifesto at drawings and pictures from different eras. If so you may be able to help date a photo by what photographer's props are visible.
Dover Publications has quite a few books on everything from clothing to hats to military uniforms. Details What details might help you date that family photo? Photography studios used painted backgrounds after 1840.
Location Sometimes a photo may be taken in front of a house or at an event.