Robert Dodds Scott and wife.2

[jim1]

Quite right. Shellac was commonly used as a backing.
Here's a similar ambro from the same decade.
You can see his waistcoat looks fastened the wrong side
& her wedding ring is on the wrong hand.
If a copy of this was taken using the negative process it
would be a faithful representation of the ambro so would
look like this (without the tinting).

[bolttail]

Many thanks. I'm now getting the idea. Would I be correct in presuming that the shellac would have to go on the opposite side of the glass to the light sensitive coating? In which case there would be no option of reversing the image. Am I correct therefore in understanding that all Ambrotype images are 'mirror images'?

[jim1]

Correct on both counts.

[bolttail]

Many thanks Jim1 for your patience in explaining all this. The people I have in mind as the subjects, the dress style, and the technology, all seem to fit together nicely, which is very encouraging. Your efforts are much appreciated.