Sorry to post this here guys/gals, but this is a real head scratcher for me. There are so many unique hobbies by members here I just wanted to see if photography was on the list.

Does anyone here know anything about old photographs? I collect antiques, and on my trip to the local antique store I aquired some very old photographs. They appear to be "cabinet cards"--meaning the photo is applied to a hard stock (paper board) backing with some decorative embossing.
I'm having a hell of a time with one photograph. It's a family photo and appears to be taken at the end of the 19th century (most likely 1880's or 1890's). The clothing of the individuals seems to support this as well. However the photo is odd. When looking at it straight on the image is not a "high gloss" type image. If you turn it ever so slightly (at an angle) it then appears as if the image is a "negative".

Also I've looked up the various types of photo developing procedures from when it first started in 1839. The imaage having a negative appearance when not viewed in the proper light leads me to believe it is an Ambrotype image. Unless I'm completely wrong by dating the clothing in the picture these types of photos faded out around 1865. To me the clothing appears to be Victorian, but no where near as elaborate as you'd find in photos from that era. The father isn't even wearing a tie, and the mother not even a hat (which was very common then). This leads me to believe they were not wealthy. Still the type of photo and the subject matter in the photo is quite confusing.

Anyone know of this photo type or developmental process?

Thanks,
Squeak